1992 Merc 3.0L high oil consumption, need advice

[griffin800]

Hello everyone! I've read over many threads here and I didn't see anything quite exactly like what I have, although there were some similar situations. I figure I will give as much info as I can up front to avoid back and forth Q&A about what it was like before and after....



Engine - 1992 Mercruiser 3.0L I/O

Stern drive - Alpha One Gen TWO

Hull - Chaparral 1800SL (18ft bow rider)

Prop - Turning point Hustler 4-blade 19 pitch

Useage - I'm on Lake George, NY. (A 32 mile long fresh water lake in upstate NY.) I'm pulling tubers and skiiers... and yes... i'm running it wide open quite a lot i guess... for what it is. My 19 gallon tank lasts me about 6-7 hours of mixed usage running marine treated 87 grade. If I want to just putt-putt up and down the lake at slow speeds I do that sometimes too and of course get better mileage



Background -

I recently Purchased this boat this spring in used but excellent condition.The Engine was clean, drive clean... interior immaculate. It was well taken care of by previous owners... however, i have NO service records.

When I took ownership, I replaced the battery with a die hard marine battery (I had one from my old 1979 Century merc 228 which I retired)

- Changed all spark plugs with the recommended Ac-Delco Marine plugs. The old ones were not burned or fouled in any way, they looked normal.

-Changed the Distributor Cap, rotor, and plug wires... just because I didn't know how old they were. The old ones looked ok...

- Checked the old/original oil which was in it when I got it (i did this before i handed over any money actually ), and while the original oil was dark, it wasn't a "milkshake".... and was right at the "full" line...

- Changed the old oil with 4 quarts of quicksilver marine grade oil... and added some Lucas for good measure.

- Changed the oil filter as well with a new one.

- Drained the stern drive fluid... it was the good blue synthetic... it had no water... no metal... and was old but clean. Filled it up with new Sierra Synthetic till it came out the vent hole.

- Replaced impeller before ever bringing it out on the water... The old impeller was still in good shape... no cracks.. no missing blades.

- Checked Trim pump fluid. It was clean and full

- Checked power steering fluid. Also clean and full.

Sorry for the long description... but In other words... I did the typical new boat maintenance and I feel I was in good shape for the season.



Situation -

Now, from the time I changed the oil, until this "incident"... I had taken the boat out at least a dozen times...

3 days ago, while out on the water at cruising speed... I heard a familiar "tapping" sound... of valves with low oil pressure. (i used to own a saab 2.0L engine which would have valve "tap" on startup until the oil pressure came up)

I checked the gauge and sure enough the reading was well below where it normally sat (normally between 30-40psi) and it had dropped down to the 10psi range... but never hit zero.

The Water temp gauge read normal... reading between 150-160 on the gauge.

I immediately shut down the engine to avoid damage... and when I removed the cover I went right for the dipstick... and was shocked to see it completely dry. Putting it and and out yielded the same result... barely any drops right on the tip... AKA empty.

Now looking around a bit, I expected to see an obvious oil leak... but there was none.

No oil in the bilge... and no oil spray anywhere inside the engine compartment...

I figured it could be BURNING oil... however... there was never any blue smoke any of the times I brought it out... and no smell from the exhaust at all.

I had 4 liters of oil onboard, and started pouring in 1 liter at a time and checking for leaks. Still nothing leaking into the bilge. I kept checking the dipstick with each liter I put in, but it took all 4 liters before the dipstick read FULL again.

I shrugged... and started it up again... while looking again for dripping / spraying / leaking oil... or smoke... and still there was nothing.

The engine idled normal, the tapping sound was gone, the gauge read between 30-40psi... (the needle just bounces a little... old gauge) water temp was between 150-160... same as before...

I took it easy back to shore... all the while fixated on my gauges... and any abnormal activity, and there was none.

Once to shore, i took it out of the water... and trailered it home.

In my driveway, I pulled the bilge drain plug and watched for any signs of oil. None.


My diagnostic testing so far-

The next day I checked the oil... it was still full on the stick.

I started it up with a garden hose and muffs. It starts right up. a little rough at first but its normal for it for about 30-60 seconds until it warms up a little... I just give it a little throttle then back down... (it's been like this since I got it... seemed normal to me, my Merc 228 was similar).

I let it idle for a bit... again looking everywhere for anything obviously wrong and seeing nothing. inside or outside: there was No oil coming out with the water from the raw water outlet, no oil coming out of the exhaust bellows...

Shut it down, pulled the plugs. All were clean except number 4. Which had some sooty deposits on it, but dry, not wet.

So... I did a compression test according to the Merc service manual (#97-27)...here are the readings.

#1 - 140
#2 - 160
#3 - 150
#4 - 120

I believe that anything over 100psi is a passing result. And with the highest reading being 160, then anything over a 112 should be ok. while the 120 reading is on the low side, only 8 psi more... it still passes by the Merc test standards...

I did the test again with a little oil squirted in each cylinder... the results were

#1 - 260
#2 - 260
#3 - 240
#4 - 240

when i say "squirt", I think i mean "too much" but at least the results were consistent.



SO...

question.

Is it possible that I am just burning oil in cylinder # 4 and the ring is slightly worn compared to the others?

Is this causing oil consumption, enough to explain losing 4 liters in maybe a solid 30 hours of engine running time on the water?

If the head gasket is ripped... wouldn't I have a milkshake dipstick?

Is there some other way for pressurized oil to slowly leak into the raw water system and exit the boat over an extended period of time??

I really dont want to overhaul this thing and pull the head less than 6 months after buying it... but I can get a "new" merc 3.0 put in at my buddy's marine shop for less than $1500 engine + labor... so...

Thoughts anyone?



Thank you all in advance for your time

-Gavin

 

[xjdriver]

Re: 1992 Merc 3.0L high oil consumption, need advice

This engine being an ohv and not ohc there are no pressurized oil passages going from block to head, just oil return passages which are not under pressure, so oil cant be entering water there, but if you have a oil cooler, i think it could be leaking into the cooling water there. If its not leaking into bilge and you dont have a leaking oil cooler than its burning it, should be white smoke with blue tint in the exhaust.
Edit- some cam in block engines do have pressurized oil passages through head, but on your 3.0 oil is delivered by the pushrods.

 

[Silvertip]

Re: 1992 Merc 3.0L high oil consumption, need advice

An engine that consumes one drop of oil per revolution will burn gallons/hour. What you are experiencing is oil consumption due to worn valve guides, rings, or valve stem seals. You don't necessarily need to see the blue haze that you used to see with a car. You also learned a valuable lesson that you check oil before you leave the dock and EVERY trip. 30 hours at 3000 rpm is a fair amount of use. 30 hours at 4500 rpm under extreme load such as your use makes an engine consume more oil. You might consider investigating the prop performance. Lugging an engine will make a "slightly" worn engine burn oil like a "severely" worn engine.

 

[griffin800]

Re: 1992 Merc 3.0L high oil consumption, need advice

This engine being an ohv and not ohc there are no pressurized oil passages going from block to head, just oil return passages which are not under pressure, so oil cant be entering water there, but if you have a oil cooler, i think it could be leaking into the cooling water there. If its not leaking into bilge and you dont have a leaking oil cooler than its burning it, should be white smoke with blue tint in the exhaust.
Edit- some cam in block engines do have pressurized oil passages through head, but on your 3.0 oil is delivered by the pushrods.

That makes sense. Thank you for the explanation.

I am familiar with engines in general, but I'm always learning. I've done a lot of work on cars of various makes and models, upgrading turbos, installing superchargers... also rebuilding the carb on my merc 228, and all sorts of maintenance on it... but I knew going into this motor that it wasn't ever used much in production vehicles... it's almost strictly marine from what I understand. I have the shop manual for it, i'll read it some more and get more familiar with it.

In any case, I saw a cooler for the power steering system, which has a water line from the thermostat housing and fluid lines from the power steering pump... but I didn't see any coolers for engine oil.

An engine that consumes one drop of oil per revolution will burn gallons/hour. What you are experiencing is oil consumption due to worn valve guides, rings, or valve stem seals. You don't necessarily need to see the blue haze that you used to see with a car. You also learned a valuable lesson that you check oil before you leave the dock and EVERY trip. 30 hours at 3000 rpm is a fair amount of use. 30 hours at 4500 rpm under extreme load such as your use makes an engine consume more oil. You might consider investigating the prop performance. Lugging an engine will make a "slightly" worn engine burn oil like a "severely" worn engine.

Yes sir, a very good lesson indeed. I will make it a point to always check now, I was going to anyways. I guess i took my 1979 Merc 228 for granted for not burning that kind of oil...

so... other than rings... which obviously requires some labor to replace... and would probably make sense to do other things while in there...

...you mention valve guides and valve stem seals. I'm under the impression that these two jobs might be easier to do, and may be worth a shot at reducing the consumption?

Is it worth my time to do the valve seals?


Also... based on my compression test... would you rule out headgasket... and say my rings are in "fair" health?



As far as limiting oil consumption by changing my boating habits...

I'm going to take it easy with this one for the rest of the season... it's not the only "ship in the fleet" for towing on,
I have no problem backing off the throttle and cruising at lower speeds.

Originally when i bought it there was a 14x21p prop on there but it couldn't get on a plane very easily with that... so i switched to the 14x19p. I did a lot of reading about it before I made the purchase and I wasn't sure if the 14x21p was the correct one for this boat either, the previous owner may have just stuck it on there for the sale... it looked almost new.

I kept it as a spare but... from what I read its for newer alpha gen 2's with the 2.0 : 1 ratio drive and not the 1.98 : 1 like i have? I could be wrong though.

In any case, with my 4 blade 14x9p prop, the tach isn't reading over 4200rpm wide open... I've never seen it rev to 4500 let alone reach 5,000.

...now... I don't necessarily trust the tach gauge... it gives me no reason not to trust it but... I'm going to hook up a big auto meter tach I have for verification next time I am out.

would a three blade prop really make that much of a difference? From what I understand it's only a little off the top end of your speed, in trade off for better planing, which this particular hull seems to have a problem with, another reason i went 4 blade.

The 19 gallon gas tank is in the middle, almost back of the boat. It's behind the driver seat... long and narrow and runs from port to starboard... so... with a full tank, 3 passengers, and myself... that's alot of weight in the back... and i usually have to tell people to move in the front so it planes out easier.

The previous owner installed the "Fins" on the drive... and I left them on there, but... I've been considering removing them and purchasing "Smart Tabs"...

Obviously a full hydraulic system would be ideal, but i think it's overkill for this boat personally.

anyways... figured I'd talk about the load the engine is seeing.

I noticed with these fins, that if i'm trimmed all of the way down, at speed... it pushes the bow way down... too much. I have to trim up a fair amount to hit the "sweet spot" and you can really feel the motor working easier at pushing it along on a plane.

I'll be taking those fins off and seeing how it feels next time.


So... bottom line... I can use it for the season if i keep a close eye on things? I shouldn't worry about a catastrophic failure any time soon if i take it easy with it?

(i know that no one can guarantee me anything here but, if it was YOUR boat and this was the situation... would you stop using it and pull the motor / work on it or... keep using it under a watchful eye)

thanks again
-Gavin

 

[bonzoscott]

Re: 1992 Merc 3.0L high oil consumption, need advice

Just my 2 cents - with those compression numbers, I don't think you have worn rings. If it were burning oil, you should be able to tell by the plugs. If oil were escaping into the cooling system, would think it would be dripping out of the exhaust / prop, but maybe not until you have run it hard for an extended period. To determine that, run it hard for an hour, then pull it out on the trailer and see if oil is coming out of the exhaust. Good time to check the plugs too. If the plugs look good and no oil dripping from the prop, only thing I can think of is - Maybe consuming oil only at high RPM, through the PCV back into the intake. At that temp and RPM, it may not be that noticeable on the plugs. With the specs you describe, I wouldn't pull / replace the motor just get. I'm thinking as last resort, take to a shop with a test tank to back the boat in. Run it up to temp and check for smoke or puddles of oil in the water. You might ask 'em to change the water in the tank before you come too .. Ha ha...

 

[griffin800]

Re: 1992 Merc 3.0L high oil consumption, need advice

Just my 2 cents - with those compression numbers, I don't think you have worn rings. If it were burning oil, you should be able to tell by the plugs. If oil were escaping into the cooling system, would think it would be dripping out of the exhaust / prop, but maybe not until you have run it hard for an extended period. To determine that, run it hard for an hour, then pull it out on the trailer and see if oil is coming out of the exhaust. Good time to check the plugs too. If the plugs look good and no oil dripping from the prop, only thing I can think of is - Maybe consuming oil only at high RPM, through the PCV back into the intake. At that temp and RPM, it may not be that noticeable on the plugs. With the specs you describe, I wouldn't pull / replace the motor just get. I'm thinking as last resort, take to a shop with a test tank to back the boat in. Run it up to temp and check for smoke or puddles of oil in the water. You might ask 'em to change the water in the tank before you come too .. Ha ha...

Thanks for the reassurance

I'm not sure if i mentioned this but, I noticed sooty buildup on plug number 4, but only on plug 4.

Plugs 1,2,and 3 look as normal / new as they did 30 hours of use ago. But number 4 looks like it's seen some burning oil. The electrode tip is clean, but the ground prong was caked with a layer of black soot buildup.

Also, when you mentioned the PCV back into the intake, I took a look at the air cleaner, and I noticed it was all blackened again where the PCV hose points to it. I had cleaned the air cleaner with carb cleaner to be spotless when I bought the boat... not sure if that's normal... but... in looking over the area under the carb, on top of the intake manifold.... directly under where the air cleaner sits... there is a layer of oily residue coating the surface of the manifold... and I didn't think much of it before since I couldn't identify this with a leak... nor did it look like typical oil seepage from an engine...

..... but i suppose as you say that oil is coming out of that pcv hose at high RPMS that it could be building up around the manifold?

The bilge doesn't have floating oil in it per say, but there is a sludgy substance down in the bottom too... it doesn't float though.... and when the bilge water drains it still looks clear... so whatever comes out the PCV hose doesn't make it that far down or... it's not acting like liquid oil.

I was looking for where liquid oil had escaped to... so i thought the small amount (no where near 4 liters of oil...) stuff in the bilge was just typical funk.

This boat doesn't have the exhaust bellows which is connected at both ends. It has the open ended exhaust bellows which was replaced as some point. So, oil would't get down to the prop.... i suppose it would only get as far as the end of that open oval end facing the stern drive...

... but i trimmed the drive up and rubbed around the inside of the exhaust bellows with my bare hand.... and the rubber feels completely clean. Also i felt around where it blows on the drive and while it was greasy feeling... it wasn't like liquid oil still... perhaps residue from burning oil?

I'm just going to run it and keep an eye on it i suppose. Maybe replace the bellows with the full double ended type...

But, I have a question...

how much oil blow by coming out the PCV is normal?

thanks again
-gavin

 

[bonzoscott]

Re: 1992 Merc 3.0L high oil consumption, need advice

Little to no oil should be passing through PCV. It is mainly fumes / gases / smoke from hot oil that PCV recirculates through the intake. It is a strange problem to lose that much oil and not find where it's going. When I read your post, my thought was that: at high RPM and high oil pressure, oil is being squirted out of the valve train excessive and the vacuum from the intake is sucking the oil back through induction. If this loss of oil was over 12 trips - 6-7 hours a trip, I would just check the oil before every trip and keep an eye on things. Clean up all oil on motor, check / change plugs and look for oil at exhaust.

 

[04fxdwgi]

Re: 1992 Merc 3.0L high oil consumption, need advice

How many hours on the engine? I have over 1300 on my 454 and it doesn't use a drop of oil between oil changes.

Plug #4 has deposits on it. Are they indeed sooty, which would indicate rich condition, or an oily film which indicates, well, oil consumption? Cyl 4 has lower compression than others (25% lower than the highest, which is a lot). Squirt in oil and compression numbers jump higher (too much oil squirted in), but more even. I would be leaning toward aged rings being worn on cyl 4. Compression could be fine, but having a stuck oil control ring (bottom ring), would cause high oil consumption, as would loose valve guides / lousy intake valve stem seals (quite common).

Sounds like the engine is just plain getting tired. Just keep an eye on oil level and have fun boating, planning on a rebuild / renew sometime in the not too distant future.

 

[griffin800]

Re: 1992 Merc 3.0L high oil consumption, need advice

Little to no oil should be passing through PCV. It is mainly fumes / gases / smoke from hot oil that PCV recirculates through the intake. It is a strange problem to lose that much oil and not find where it's going. When I read your post, my thought was that: at high RPM and high oil pressure, oil is being squirted out of the valve train excessive and the vacuum from the intake is sucking the oil back through induction. If this loss of oil was over 12 trips - 6-7 hours a trip, I would just check the oil before every trip and keep an eye on things. Clean up all oil on motor, check / change plugs and look for oil at exhaust.

Thanks again for your reply! The way I worded that question made me sound like a rookie I knew that liquid oil wouldn't come out the PCV, but i was curious about how much could acutally be burned off through the PCV system in hot fumes form... but I agree it's very strange to not find a telltale sign of where it all went in the 12 trips at 6-7 hours per trip.
Thats pretty much exactly the amount of useage it saw from when i put in 4 quarts, a new filter and lucas oil till when it was empty.

I'm going to run it a few more times and take it easy on it, and try and estimate how much it uses in a trip if i can... and maybe report back any findings. I may be able to find a place to run it in a tank and check the exhaust. I would like to know if it leaks that much out, as I would feel bad about polluting the nice lake we have up here in the Adirondack park.

How many hours on the engine? I have over 1300 on my 454 and it doesn't use a drop of oil between oil changes.

Plug #4 has deposits on it. Are they indeed sooty, which would indicate rich condition, or an oily film which indicates, well, oil consumption? Cyl 4 has lower compression than others (25% lower than the highest, which is a lot). Squirt in oil and compression numbers jump higher (too much oil squirted in), but more even. I would be leaning toward aged rings being worn on cyl 4. Compression could be fine, but having a stuck oil control ring (bottom ring), would cause high oil consumption, as would loose valve guides / lousy intake valve stem seals (quite common).

Sounds like the engine is just plain getting tired. Just keep an eye on oil level and have fun boating, planning on a rebuild / renew sometime in the not too distant future.

Thank you too for your reply fellow Chaparral owner Honestly, I don't know how many hours are on the engine. Unfortunately I didn't buy it from the original owner. A long time friend of mine, who I trust, works as the sales manager at a local marina on Saratoga Lake, and had taken the boat in on trade. He wasn't given any service records with it, and never gave me an idea as to how many hours were on it.

With it being over 20 years old, and myself looking at the engine's physical condition before I bought it... I figured it to be the original engine... VS a repower, although I guess I'd never know. (I'd think also if it was repowered at some point the previous owners would have for certain saved that paperwork to increase the value of the boat in trade... so... again it pointed to the original engine for me.)

I tested it out before I bought it, and it always started right up on the first second of cranking. .. idles smooth... gets on a plane... and cruises as fast as I need it to go. I don't need a speed boat to have a good time. (My lake has a strictly enforced 40mph top limit anyways... heavily patrolled in summer)

So, for the low price I paid for it... and the good condition it appeared to be in... I had no problem not knowing the estimated hours of use on it. In hindsight... could it have been a mistake? Sure... but I'm married to it now



Also, to better describe the plugs condition, I will say that the black substance on it had to be scraped off lightly by my finger nail, rather than wiped off with a cloth. It was more solid in nature than liquid, if that helps.

I could take it out again for a photo but I think i cleaned it up already for the most part so I could check it after the next trip and see how it looks. In any case, I thought it would be possible that the heavier / more solid material deposited on the plug could have been residue left from oil being burned in cyl #4, rather than the liquid oil itself?

I guess I'm just patronizing myself... wishing this weren't the situation with a boat I just bought less than 6 months ago... hoping I didn't have to rebuild / repower it so soon after buying it....

But, I will say... the hull, drive, electrical, interior, and even trailer... are all in great condition... It came with brand new covers made, too... and I suppose if I repowered it, it would be worth it.

I'd like to share some photos of it with all of you, and you'll hopefully agree that it is probably worth the time to put some engine work into if I have to.

http://flickr.com/gp/7783766@N05/Q507SE/

So from reading the shop manual, it looks like a valve seal job wouldn't be impossible to do with the engine in the boat? What about valve guides? Any write ups on these? (guess I should start googling myself eh?)

Thanks again everyone for your help, I'll report back this week after taking it out on any findings or new info I come across.

-Gavin

 

[04fxdwgi]

Re: 1992 Merc 3.0L high oil consumption, need advice

Valve guides are done by the machine shop and head has to come off for that. I think your problem is with the rings, with those compression readings. May be time for a rebuild. That little 3.0 is easy to do (I did a couple of them) It's nothing more than the old Chevy II 153 CI motor with a few more CI. Basically 1/2 of a 327, if you will.

 

[bonzoscott]

Re: 1992 Merc 3.0L high oil consumption, need advice

That is a sharp boat! I seen you're entire problem in the photo. It's that Keystone! JK . I'd just keep an eye on the oil at least for a couple of seasons.

 

[04fxdwgi]

Re: 1992 Merc 3.0L high oil consumption, need advice

That is a sharp boat! I seen you're entire problem in the photo. It's that Keystone! JK . I'd just keep an eye on the oil at least for a couple of seasons.

Keystone??? I agree 100% with he should just keep an eye on the oil and have fun.

 

[griffin800]

Re: 1992 Merc 3.0L high oil consumption, need advice

Valve guides are done by the machine shop and head has to come off for that. I think your problem is with the rings, with those compression readings. May be time for a rebuild. That little 3.0 is easy to do (I did a couple of them) It's nothing more than the old Chevy II 153 CI motor with a few more CI. Basically 1/2 of a 327, if you will.

Well I'm not opposed to putting the money into it... i would even consider doing it myself if it's not that hard of a job in theory.. but I don't have a place to really work on a big project like that right now. The neighborhood I live in wouldn't really go for a big engine rebuild project in the driveway that I have. :/ I guess i could bring it to a friends farm, but not being able to tell them how long it would be there for sure, with machine shops needing to be involved... or ordering parts that need to be unexpectedly replaced.... or the general craziness of my work schedule coupled with the 20 mile one way drive to his farm... it makes me nervous about the logistics.

In other thoughts, I see you're in south east NY, I'm probably not that far from you. Wanna do another rebuild?

That is a sharp boat! I seen you're entire problem in the photo. It's that Keystone! JK . I'd just keep an eye on the oil at least for a couple of seasons.

Thanks for the compliment! It looks sharp to me too, wish it had the 4.3L in it, then it'd be as fast as it looks

Hahaha Yes, keystone light IS a problem, i should have spent a few more dollars on better beer.

Keystone??? I agree 100% with he should just keep an eye on the oil and have fun.

(there is a photo in my album link above, of the boat in the water with a keystone in one of the cupholders)



So, I took the boat out yesterday... and I did a few things to it before bringing it out.

1. I cleaned out the bilge with bilge cleaner so i could easily spot any oil if it was leaking.

2. I changed the belts, both power steering and alternator / water pump.

3. took off the doel-fins to see if it helps not bog the engine down at cruising speed

4. checked the of oil of course


I brought it out on a trip on the lake again... and i took it very easy. I didn't get to try another tachometer... but basically I believe this one reads correctly everywhere under 4000.
(I just want to double check my max RPM someday with another tach to b double sure. Call me paranoid)

So... still no smoke... no bad odors... and no rough running while in the water... same as always. With the new belts properly tensioned, the water temp gauge ran quite a bit COOLER than it did before... hovering around 140-150 at speed and immediately dropping down if i came off plane and idled around. (the old belt was very worn and i heard it squeal a few times)

ANYWAYS... I puttered up the lake not even on a plane... just at about 1800-2000 rpm... a lazy day cruise. It took over an hour to reach a destination that normally takes a quarter of the time... I tried planing it out once but without the fins it didn't want to plane with 2 people in the back... I asked them to move to the front seats for me... and it planed... but of course those two times I tried I had go push the throttle hard... and while I didn't hear, smell, or feel anything weird from the engine... I decided to drop off plane and putter instead, until I knew how much oil it would be using.

So, in at least 10 miles of practically idling up the lake... we went swimming for a bit, had some snacks (boating is supposed to be fun, remember?) ... I took off the engine cover and checked the oil...

It was still hovering right around the "full" line. With the boat not sitting quite level in the water with the weight distribution, I figured it was close enough to full, but for safe measure I put in half a quart.

During my visual inspection, i did see one single solitary drop of oil on the end of the PCV hose... about to drip on the manifold. I reached out with my finger and touched the droplet... and rubbing it around it seemed like clean oil.. it wasn't black.

In the water I felt all around the prop and the drive and there was a black greasy substance where the exhaust bellows blow on the drive... not liquid though more like from exhaust fumes with burning oil...

In any case... we already knew that, i just figured I'd check to see the effects of it.

But, it was quite a relief to see it wasn't burning it so quickly that i couldn't go to my favorite spot for swimming...

On the trip home I was able to get it on a plane by having people in the front, hitting WOT very briefly to get on a plane well before 4000rpm, then adjusting the trim a bit and backing down to only 3100-3200rpm on the tach.

The engine sounded happy and the cruise speed was fast enough to get us back to the dock in at least half the time...

it was getting late-ish and I couldn't mess around with taking the cover off to check the oil... had to get out of the water and go... but i figured I would check it before going out next time and I'd see the effects of how much it consumed on the approximately 10 mile trip back at cruising speeds....

hopefully it's still hovering around full, and I can use it like this for the rest of the summer... and I'll think about engine work at some point next year.

I can't decide if it makes more sense to rebuild what I have or to just buy a long block and sell mine in the condition it's in... as running but "tired"...

I usually keep it in a winter storage facility for about $200 for the winter, and they have very specific dates that they want it put in and brought out of the facility... with no access to it myself... If i dropped the boat off somewhere to a shop that would work on the engine over the winter... maybe that would make more sense... just thinking about the future...

anyways, that's all for now. Thanks again
-Gavin

 

[04fxdwgi]

Re: 1992 Merc 3.0L high oil consumption, need advice

Ahhhhh. I see now, Keystone beer. Yup, could be a problem. Least it aint Ol' English 800.. LOL. Nice pics and a sharp lil 1800. Do like the older Chaps, obviously.... Here's my '92 2550 SX Sport on Lake Sunapee, NH

 

[alorio1]

Re: 1992 Merc 3.0L high oil consumption, need advice

You and I have the same boat with same engine. Like you I can run all day on a tank of gas pulling kids on the tube, knee boarding ect. My boat was purchased from a meticulous owner and always kept inside a garage so it looked show room new when I bought it. My engine has never used any oil, but I have noticed a light coat of oil right beside the carb after running all day at WOT getting on plane while pulling. But If my little engine ever goes south on me I will surely rebuild it or replace it with a remanufactured engine. I boat with others with larger engines and usually go the same distance/routes as I do. They maybe can go faster but for the extra 5MPH it cost them quiet a bit more to run all day. I would run the engine until it starts loosing power or oil consumption get worse.

 

[aerobat]

Re: 1992 Merc 3.0L high oil consumption, need advice

I had 4 liters of oil onboard, and started pouring in 1 liter at a time and checking for leaks. Still nothing leaking into the bilge. I kept checking the dipstick with each liter I put in, but it took all 4 liters before the dipstick read FULL again.

are you absolutely sure on these numbers ? i have a volvo 3.0 but its the same GM block. the 3.0 has an oil capacity of 3.5 quarts without oil filter and 4.0 quarts with oil filter.

so filling in 4 quarts is almost impossible without overfilling it even when the engine was bone dry but filter unchanged.

further - an engine that BURNS 4 quarts in 30 hours would smoke blue like hell and run like crap, thats for very sure - but your compression numbers do not show a tired and worn engine .

i would carefully observe it only to first verify your numbers are right before starting to work on this engine.

cheers

 

[Silvertip]

Re: 1992 Merc 3.0L high oil consumption, need advice

Valve guides are done by the machine shop and head has to come off for that. I think your problem is with the rings, with those compression readings. May be time for a rebuild. That little 3.0 is easy to do (I did a couple of them) It's nothing more than the old Chevy II 153 CI motor with a few more CI. Basically 1/2 of a 327, if you will.

Half of a 327 would make it a 163.5. The four banger in Chevy II days was two cylinders chopped off the inline six cylinder. The 3.0 had it's roots in the Chevy II motor but it was never used in a car at the 3.0L displacement.

 

[Silvertip]

Re: 1992 Merc 3.0L high oil consumption, need advice

Once again I bring up the propeller issue. While a 19P may be spot on for "cruising", it may not be the best choice for towing. Just like towing a trailer with a car or truck, axle ratios play a big part in how a vehicle performs and a wrong selection can cause engine damage over time due to "lugging". As you try to get someone up on skis, pulling a tube or wakeboarder, the engine is under heavy strain during hole shot. That requires very high throttle settings which results in very low manifold vacuum readings. During that time is when anything worn (even slightly) such as the rings and valve guides and seals allow oil consumption to rise. The fact that you have obvious blow by in the crankcase vent system verifies this. Changing valve stem seals is not worth the effort if the guides themselves are worn. If you do have cylinder head work done, specify that the machine shop use Perfect Circle "umbrella" type valve seals. There are others like them so the brand name was just one to indicate what you desire. As was mentioned, an engine would need to consume huge amounts of oil to see it dripping from the exhaust so don't bother with that test. My suggestions would be to borrow a prop from a friend or visit a service facility to see if they have a 17 or 18P (three or four blade) you can rent on a trial basis. Then buy from them if you find it solves the problem. Don't delve into the engine until you assure yourself the boat is propped correctly for the severe loading you are placing on it during hole shot.

 

[griffin800]

Re: 1992 Merc 3.0L high oil consumption, need advice

Wow! So many replies! Thank everyone for taking the time to read my long post! I know I can be very "wordy"... I've actually been scolded on it before at my job. I do I.T. work for the Chicago Tribune Company in a Data center here in upstate NY. I've been asked before "Do you know the meaning of IN TEN WORDS OR LESS" So.. anyways i appreciate you all picking through my posts for the info. I'll try to do a multi reply here:

Ahhhhh. I see now, Keystone beer. Yup, could be a problem. Least it aint Ol' English 800.. LOL. Nice pics and a sharp lil 1800. Do like the older Chaps, obviously.... Here's my '92 2550 SX Sport on Lake Sunapee, NH

Ha, yeah... if i said it was my "friend's keystone" would anyone believe me? I like the look of the older chaps too, I wish mine was a little longer like yours, sometimes I find myself shuffling stuff or people around to get it all to fit.

You and I have the same boat with same engine. Like you I can run all day on a tank of gas pulling kids on the tube, knee boarding ect. My boat was purchased from a meticulous owner and always kept inside a garage so it looked show room new when I bought it. My engine has never used any oil, but I have noticed a light coat of oil right beside the carb after running all day at WOT getting on plane while pulling. But If my little engine ever goes south on me I will surely rebuild it or replace it with a remanufactured engine. I boat with others with larger engines and usually go the same distance/routes as I do. They maybe can go faster but for the extra 5MPH it cost them quiet a bit more to run all day. I would run the engine until it starts loosing power or oil consumption get worse.

Same boat at me eh?

That's great! I've had a few people on this thread ask me about prop performance... and I'm hoping you could tell me what you run on yours?

If you're running all day and towing people sometimes then it seems like we're using ours in similar ways.

I also don't really miss the extra 5mph I had when I was running a small block chevy v8. it would go through 20 gallons of gas in 5 hours no matter how I ran it. lol. But then again, different hull, different prop... different animal... and still same old throttle happy me driving it. I'd like to feel like the 3.0L gets better mileage, although It may not be leaps and bounds better the way I was using it.

I do have a friend with a 24 foot searay with a 50 or 60 gallon tank... and I know i wouldn't want to pay for that all the time

I'm glad the light coat of oil near the carb is something you find normal too. And I do agree with you I think, that if the engine goes south that because the hull and interior are so nice.. it'd be worth it to just go with a reman long block and drop it in. Maybe I'd even get an "Hour Counter" at that point just to keep track of the hours on the new engine.

are you absolutely sure on these numbers ? i have a volvo 3.0 but its the same GM block. the 3.0 has an oil capacity of 3.5 quarts without oil filter and 4.0 quarts with oil filter.

so filling in 4 quarts is almost impossible without overfilling it even when the engine was bone dry but filter unchanged.

further - an engine that BURNS 4 quarts in 30 hours would smoke blue like hell and run like crap, thats for very sure - but your compression numbers do not show a tired and worn engine .

i would carefully observe it only to first verify your numbers are right before starting to work on this engine.

cheers

I said liter when i should have said quart... although i think the conversion is about the same. Anyways... I'm sure I put 4 in... and I'm not sure if I overfilled it that day or not.

When I first did the oil change upon taking ownership of the boat... I drained it all, and I changed the filter... and I put in 4 quarts, with some Lucas oil additive.

when the dipstick was empty... honestly I was in a state of shock, aka borderline panic. I half expected to be losing oil in a leak somewhere that perhaps I couldn't see... and I figured even if I overfilled it by half a liter... it may have been losing it so fast on the nearly 10 mile trip I needed to make just to get back to my dock and trailer that it wouldn't matter.

I had quite a lot of distance to cover in wide open, deep water... getting late in the evening with not a lot of people around... and my #1 concern was making it back to the dock ASAP to avoid the $200 upfront fee that the emergency tow services charge on the lake here.

I've heard it's bad to overfill... obviously in an engine it is... but i've heard that perhaps this engine it is bad to overfill particularly? but I'm not sure why.

in any case... after getting back to the dock and trailering it home, i've run it in the driveway on muffs and adjusted the level of the trailer back and forth to try and get the engine level to check the oil.... it sits right at the fill line now... it's not overfull anymore...


Now i'd like to share an important piece of information here...

I took it out the other day, ran it in the driveway to warm it up... and once at operating temp... and everything running smoothly...

I would hit the throttle for quick blips revving it up to just under 3000 very briefly and then backing off quickly...

and.... there IS smoke coming out of the exhaust. A light cloud of smoke actually... that slowly expands behind my boat and moves off like mist into my backyard and adjacent neighbors yard.

It's enough smoke when I did it the 3 or 4 times to look at it, that I was honestly worried that my neighbor would come out and yell at me for running my boat and filling half his backyard with smoke...

Did it have a blue tint to it? Kind of... it wasn't thick smoke, and while white in nature it wasn't like a cloud white... so...

in any case it is burning oil... and making smoke... just guess its not enough to come up through the surface of the water when i'm running it.

Once again I bring up the propeller issue. While a 19P may be spot on for "cruising", it may not be the best choice for towing. Just like towing a trailer with a car or truck, axle ratios play a big part in how a vehicle performs and a wrong selection can cause engine damage over time due to "lugging". As you try to get someone up on skis, pulling a tube or wakeboarder, the engine is under heavy strain during hole shot. That requires very high throttle settings which results in very low manifold vacuum readings. During that time is when anything worn (even slightly) such as the rings and valve guides and seals allow oil consumption to rise. The fact that you have obvious blow by in the crankcase vent system verifies this. Changing valve stem seals is not worth the effort if the guides themselves are worn. If you do have cylinder head work done, specify that the machine shop use Perfect Circle "umbrella" type valve seals. There are others like them so the brand name was just one to indicate what you desire. As was mentioned, an engine would need to consume huge amounts of oil to see it dripping from the exhaust so don't bother with that test. My suggestions would be to borrow a prop from a friend or visit a service facility to see if they have a 17 or 18P (three or four blade) you can rent on a trial basis. Then buy from them if you find it solves the problem. Don't delve into the engine until you assure yourself the boat is propped correctly for the severe loading you are placing on it during hole shot.

I've asked the other chap 1800sl owner above what prop he is using... but I'm open to trying other props.

I bought this Turning point "Hustler" Prop because they market is as for watersports... but they say that because of it's design, you don't have to choose a lower pitch than a 3 blade...

for example if you used a 17 pitch 3 blade for top speed they claim that you would use their 17 pitch hustler 4-blade and it would give you better hole shot without needing to change the pitch.

The hustler prop series has an alternating blade design which they claim gives you the "best of both worlds"

now... could this be marketing hype? Maybe... but it seemed to get a lot of good reviews... and I got it on amazon.com through amazon prime for a good price with free shipping...

I did quite a lot of reading about this engine and what people felt like the best selection for a prop was, and I kept hearing that the best performer was the 19p 3 blade...

One thing I didn't want to do was prop it too small and have to worry about over-revving the engine... if a 17p runs the risk of getting me over 4600rpms at WOT it makes me nervous because if anyone else drove my boat and didn't know this... or... just didn't pay attention even if I told them... well... it'd be bad

Not that my engine isn't already acting up

So, I will try a 17p 3 blade and see how it goes...

I've told everyone NO more towing until the engine is fixed... and they're fine with it. There are other people with faster boats and bigger engines that DON'T burn oil for them to hang out with... plus... maybe only 1 in 5 people I towed around actually chipped in for gas anyways. haha

Needless to say, a perfect holeshot isn't my concern anymore... now that i'm not towing anyone.

And... it's planing out good enough for me right now with the 19 and just cruising. I'm curious to try a smaller prop but....

with this prop... from a dead stop in the water... with me and 2 passengers... one in the front, one next to, or behind me...a full 19 gallon tank of gas (tank located behind driver also, not in bow) and a 40 pound full cooler...

...I will gradually push the throttle down... getting close to or at WOT for only a few moments... before it starts to plane out... and it's on a plane before I hit 4000rpms.... then I back off the throttle, adjust the trim, and I cruise at 3100-3300... which is fast enough for me to go...

my spedometer has never worked in this boat but i have a handheld GPS i checked it with before. I only ever topped out at 31mph with this prop and a similar load... on smooth glass water conditions... so... I knew it wasn't a Fast boat... and that was at higher RPMS last time I checked...

I'm sure the 3100-3300 cruise range is like 20-25 somewhere in there... ill bring my handheld to check again but... I haven't had any complaints about it being too slow or being too fast from anyone so...

there's all the info I can think of about the prop.

I can borrow a 3 blade 17p from a friend and report back sometime tho, I do hear what you are saying. A positive effect would be hole shot improving, but for my engine and the large distances i need to cover on this lake... i wouldn't want to have to rev the engine any higher than 3300ish to cruise along... it doesn't feel like it's being lugged right now.

Also, thanks for the advice about the seals. I was looking at ebay auction number 321007276641 for those type of seals, if i was ever going to do the valve job myself.

thanks again everyone!

-gavin

 

[04fxdwgi]

Re: 1992 Merc 3.0L high oil consumption, need advice

Half of a 327 would make it a 163.5. The four banger in Chevy II days was two cylinders chopped off the inline six cylinder. The 3.0 had it's roots in the Chevy II motor but it was never used in a car at the 3.0L displacement.

Was just making some light hearted comments about the little 3.0 and stating it was of the 153 CI design family, that's all. They are an awesome engine, especially when worked on a bit. I built an early Mercuiser 140 w/ 30 over pistons, beefed up valve train and had Dave Crower (of Crower Cams) heal grind the cam for some extra lift. Had to heal grind as he had no cam blanks for the 153 family of engines. Little booger would give V6's a run for their money. And yes, 153 family parts (and a few valve train parts that fit 327's also) were used in the build.