Noisy '78 115 Evinrude Paranoid or Problem?

[shirthero]

Bought an 18' '78 model Glastron with it"s original '78 Evin 115 V4, We've run it 4 or 5 times in the last month, starts idles runs real nice was owned by an older couple and was meticulously maintaned. Today we pulled a tube for the first time and it seems the engine is very noisy, a knock or tick when it's under load. Idling it is not noticable and while waiting for the trailer
I ran it out and blasted to a blazing 36 mph with the noise seeming much less. I have read on here that crossflows are noisy/ticky. I'm gonna change the plugs and do the "pencil test" on the pistons to check for bearing play, but what else would account for this? I really don't think it is a rod knock but sure made me paranoid today.

 

[emdsapmgr]

Re: Noisy '78 115 Evinrude Paranoid or Problem?

Does it make the noise when in gear, or at idle? Could be something in the lower unit. You should remove the plugs and put a small light into each cylinder. Check for any pits on the piston tops or scuffing on the cylinder walls.

 

[shirthero]

Re: Noisy '78 115 Evinrude Paranoid or Problem?

In neutral it is not noticable, at idle or if I lift the warm up lever to rev it up, put 2 kids on the tube wot in gear it seemed pretty loud to me.

 

[shirthero]

Re: Noisy '78 115 Evinrude Paranoid or Problem?

Did the pencil test, found no play, all pistons and cylinders look good, little carboned up, will seafoam the next few days. With the plugs out I put the shirter in gear and turned the prop by hand, was able to turn it easily enough but was not glass smooth, should I feel much doing this or should it be completely smooth? Little noise if I wiggle the crank back and forth, hard to tell if it was at the baseof the powerhead, or lower in the gears. I pulled a sample of the lower unit oil to see if there was any water or metal shavings in it, I did not see any "glitter" and it didnt seem milky to me, I've attached a pic of my specimen sample for you pros to look at. The oil has 5-6 hrs on it, smells normal, not burned. Opinions welcomed.............

 

[emdsapmgr]

Re: Noisy '78 115 Evinrude Paranoid or Problem?

The lower unit oil looks ok. What is the compression on each cylinder? Would be nice to isolate the problem between the lower and the powerhead. You might want to remove the lower unit, then plumb the garden hose to the water pipe at the bottom of the midsection-then start the engine. If the noise went away, you have your answer. If you feel it is still there, it is in the powerhead.

 

[handyfella]

Re: Noisy '78 115 Evinrude Paranoid or Problem?

Well, call me stupid, I mean I do actually own a compression gauge, the guy just seemed so honest and even said he checked it and got 120psi straight across all 4.. Well, I took this boat out AFTER buying it from him, (yeah dumb, it's just a good condition hull and a seemingly honest seller so I jumped)..

Well, I too noticed the same noise (yes I am certainly POSITIVE it's the same boat, the guy runs a T-shirt business in Tulsa) It's a rather loud tick tick tick synchronous with revs.... I too thought maybe a bad prop shaft.. But read on..

Can't find his # anywhere but would it really help??

So I pulled the plugs and checked compression. I get 130, 132, 135, 115psi .. Put a small led in the low hole and see a GNARLY piston top, just banged up chewed up or whatever, looks like the surface of the moon.. There's also some scuffing in there that MIGHT be aluminum galded to the liner and can possibly be removed with some acid... Man am I stupid.. Never heard anything in the way of noises or ticking running on the hose..

The guy says "oh man I would take my family out in that boat".... geez..

Well I scored an oem crossflow std bore piston & rod with rings for $40 and only 30 hrs on them looking brand new. Is it ok IF I can get the cyl. to hone out, to just swap this piston in, run double oil and do the full tank idleing for hours for a single break in?

Any help would be great, I DID also ALREADY buy a NEW $100 cover, AND installed a nice OEM trim unit, have $300 in that with misc wiring and relays/switches and lots of time, and the unit works great...

I got an exact 35.67mph gps several times, hits the same rpm every time, yet the slightly scuffed weak cylinder has remained running for who knows how long???? Well maybe he was really honest and all, but I don't see how he thought the bores looked fine, one piston is badly pitted... It was my stupid fault... Anyhow a one hole job is all I'm after and would love some help on how to tackle this the easiest way.

I am very tempted to just hylomar the orig gaskets back together and see how many more years (decades??) I get out of it.. I will be starting a new job soon and a new outboard won't be out of the question but would love to get this one back together for the summer..

THANKS for any help.. And to the OP, If you care to pay for parts I won't hold it against you if you ever read this!

 

[emdsapmgr]

Re: Noisy '78 115 Evinrude Paranoid or Problem?

The crossflow engines will make noise when they get high hours on them. Called piston slap. Once the pistons and bores wear with age, they can be noisy. It's not a specific problem, nor is it a prelude to a catastrophic failure. But they do get noisier with lots of hours on a powerhead.

 

[handyfella]

Re: Noisy '78 115 Evinrude Paranoid or Problem?

Thanks for the reply but as it states above starboard upper cylinder is 15psi down from the rest and there is visible scuffing on bore plus lots of big nasty chunks taken out of the piston top. The noise in this engine is the piston rings passing over the galded aluminium chunks adhered to the cylinder wall and catastrophic failure on this cylinder basically has already happened. What I see in this engine is three perfect bores and pistons and one that's in bad shape with a beat up and brroken piston ajd I am just hoping I can remove the aluminum with acid and hand hone any rough spots and or hopefully light scoring and just ignore the blowby afterward.

Thanks for the reply definitely, and I might add that I really don't think this motor has very high hours on it.. i think my gauge reads high but am pretty sure the comp #s are really 120 122 125 105. The whole scale could be off a little..

The guy was bragging about dragging a 8ft wide tube with this little 115 so I'm wondering if that didn't cause an overheat ??

 

[emdsapmgr]

Re: Noisy '78 115 Evinrude Paranoid or Problem?

Common for a crossflow to throw a ring. Usually not from pulling tubers. Can be caused by a lean condition (carb restriction) or a water cooling issue around that cylinder (debris in the passages) or coking of the rings (carbon buildup.) Any of these can cause a top ring to break due to overheating/lack of lubrication. When it breaks, it will eventually catch a port and disintegrate, going into the combustion chamber where it will beat itself into bits between the head and piston crown. You may find ring bits in the lower unit exhaust area. Check the positioning of the rubber water diverters in the powerhead when you take the bad head off.

 

[rtek816]

Re: Noisy '78 115 Evinrude Paranoid or Problem?

I'd caution you on doing a 1 hole rebuild with a vintage rude. I have a 86 140 that dropped a piece of ring and my first rebuild was new rings all around and a new standard piston and head on the port side. Got 140 hours out of it and am in the process of doing it again. I had a reputable machine shop bore gauge all holes and decided to go .030 over on all 4. First check on hole size (brother in law) found all to be in spec (can't spell machinist but is one). Toughest part was finding another head. BTW, my cylinder spit the ring due to being worn out. .0095 out on top and .004 on bottom. Oversize and out of round, the ring catches on the port and busto. And definately replace that head or it will run like cox airplane engine, with glow plug.

 

[rtek816]

Re: Noisy '78 115 Evinrude Paranoid or Problem?

I should have mentioned my engine had 1400 hours on it last year when I rebuilt her. I did replace all fuel, oil, primer and vent lines as well as rod bearings, cap screws and gaskets/ seals. Rebuilt the VRO pump and 4 carb kits. I've known this boat since new and purchased it from the estate of my deceased fishing buddy. I am replaceing all removed gaskets again as I don't want to save $15.00 and have a leak (will cause a lean run and you'll get to do it again). On the positive side, I know more about this engine than I wanted to but will feel much more confident in knowing it is right and will get me back to port. I like fishing deep water on Erie, usually 10 miles out in the middle of summer. My $.02.

 

[handyfella]

Re: Noisy '78 115 Evinrude Paranoid or Problem?

I wonder if welding the head is an option with a tig and fill in the holes that way..

Thanks for the response for sure. And 140 hrs sounds like way more than I need out of er btw.. and I really don't think this motor has anywhere near 1400 hrs btw!

So about procedure for a 1 hole piston swap can I pull the intake with carbs attached if I'm slick enough ? After that it's Reed block and I'm there correct ? Of course head comes off..

 

[wilde1j]

Re: Noisy '78 115 Evinrude Paranoid or Problem?

Don't waste your time with the bad head. See 'salvage yards" under the sticky at the top. Easy to find a head.

 

[rtek816]

Re: Noisy '78 115 Evinrude Paranoid or Problem?

shirt or handy, Don't think you can get the rod cap off without splitting the case. The reed plate doesn't allow enough clearance and you'll be fighting trying to catch all the needles (pretty sure they are uncaged). and you have to deal with honeing a cylinder still connected to the cases. To many more things to go south IMO.

 

[handyfella]

Re: Noisy '78 115 Evinrude Paranoid or Problem?

Well, youre right, I pulled the intake mani tonight just enough to see the rods are totally inaccessible without splitting case halves..

The slight amount of scoring in the low cyl. was hardly enough to catch a nail on, and the top ring is exposed by a chipped piston ring land right along a smaller port. I used some emery cloth and slightly honed the scored area both directions and it was much smoother. I also checked the out of round at the top which is probably not the right way to check for cyl. roundness, but at the top I got 3.501" all the way around the hole so that means my std bore piston I got on ebay for $40 will fit I think but maybe my roundness check is mostly inconclusive. The plus side is that I think it will run fine with the new piston for a long time if i can correct whatever caused this in the first place (carbon buildup??)..

How simple is this? I'm seeing a cover under the main base of the engine compartment that looks like it needs to come off, then misc. wiring and starter, control cables, etc., then bolts, then lift powerhead off, get necessary gaskets, maybe r/r the head due to dings, re ring all 4 and do a break in procedure. But the compression is high enough i wouldn't think it would need any work on the other 3 holes..

Thanks for any replies, or the $400 check in the mail Im sure the OP will be sending me to comp me for this hassle he declined to disclose when selling me this boat as a "great runner with zero problems"...

shirt or handy, Don't think you can get the rod cap off without splitting the case. The reed plate doesn't allow enough clearance and you'll be fighting trying to catch all the needles (pretty sure they are uncaged). and you have to deal with honeing a cylinder still connected to the cases. To many more things to go south IMO.

 

[handyfella]

Re: Noisy '78 115 Evinrude Paranoid or Problem?

Well I got a low hours piston with rings and rod attached on ebay for $40 shipped which the guy claims it had 30hrs and had almost zero carbon anywhere, swapped it in yesterday, reinstalled powerhead today, used black rtv on intake mani instead of gasket, and used red rtv on base of powerhead instead of gasket, also sealed case halves with hylomar instead of gel seal.

I let the rtv cure for several hours, fired it up, and shot starting fluid around intake manifold base and no leaks..

I had to clean up the combustion chamber on the bad hole that threw part of a ring due to what I believe was cause by carbon buildup.. I used a file, a hammer, and a punch, and flattened and smoothed the mangled area with fair results, looks much better and got rid of the sharp points and sharp dimples left by the sharp edges of the broken ring.

It was a bear wrestling the powerhead with a $5 rope hoist (block and tackle), but was much easier than trying to set it by hand. (I actually set my mariner mag 150 by hand over 10 years ago without help or a lift, yes, the 2.0 liter V6 150, and I don't know how I did it, but maybe it was due to being 18 and hardheaded )

So it seems to be running really well, will check compression #'s tomorrow, and I am trying to figure out what the best way to get these rings to seat and sort of break in, since they are already broken in on another bore that is..

I checked the cylinder roundness and they are within .0005" roundness at the top of the bores, don't have a bore gauge handy to check it down in the hole, but the motor seems to be low hours and is very clean inside and out.

Any recommendations or corrections on what I've done is welcome. This was totally unexpected, rough, and a let down, but I think I may have the problem rectified, and the newer piston has the redesigned ring land which is thicker and stronger so maybe that piston won't fail anytime soon.

My real question, how do I break a used piston and ring in? I even reused the rod bearings, because this is a used motor and I just don't see the difference if it runs two more years that's all I need it to do, heck maybe it'll run 5 more who knows.

Matt

 

[emdsapmgr]

Re: Noisy '78 115 Evinrude Paranoid or Problem?

The bore does not wear at the top of the cylinder, the wear is towards the mid and lower portions of the cylinder liner. That's a good place to measure for wear. Esp, around the port area of the cylinder liner. Carbon buildup in those crossflows can be kept at a minimum if you do a Decarb every year. Also, Bombardier makes an XD50 oil which has a carbon preventiative additive mixed in the oil and works while you run the engine. Also, carbon can build up if the thermostats stick open, or if they were removed, causing the engine to run cool. Cool running engines have poor combustion and can promote carbon buildup internally on the ringsets.

 

[handyfella]

Re: Noisy '78 115 Evinrude Paranoid or Problem?

Compression after piston replacement is 130,130,131,127 lowest being the newly replaced piston...

Have run maybe 15 gallons through it with double oil and it will idle all over the lake all day long..

Update on the noise, ticking, it was NOT the piston/ring catching, it was the LOWER UNIT! Forward gear is missing a tooth, so $400 later I have a mid 80's unit that holds 15psi just fine and the noise is totally gone under load...

After replacing the piston/rings in the top driver side cylinder (starboard??) I have gotten a few scuffs here and there, so I have emery cloth'd those scuffs out that couldn't even catch a nail and I can still see my new crosshatching across the small score lines, and I will just be idling it around for another 10 or 20 gallons or so, and hope that the piston and rings will get very comfortable in their new bore and keep the heat down while doing so. It will holeshot just fine but I'm just going to putt it around and use it for swimming etc. and hopefully the scoring will not grow as it hasn't so far.

We've just been trolling around enjoying the lake and watching fireworks and when idle'd only it seems to be polishing the bore really well and is not losing compression fromwhere it started.. The scores I cleaned up aren't growing up the cylinder, they are staying put and not reaching all the way up to the top of the cyl..

Would the slightest bit of trash or dust on the piston/rings or carbon I didn't clean out from under the rings do this type of scoring and eventually clean itself out and seat the rings right eventually?? It is running really well and the ticking is gone...

I will probably just plan for a full .020 or .030 over with 4 new omc pistons rings bearings etc. anyway in the near future since I know what I'm working with and it's a light and easy powerhead to shortblock but it seems it will keep running for a while for just cruising around and swimming. I don't really see the point in flying down the lake and trying to flip peoples small fishing boats over anyway, and you get plenty of that here in Arkansas..

It seems two strokes will run a long time with a little scoring anyhow..