Sticky rings??

[Hotrods]

Hello again all. Here is my question. I have a 1993 Evenrude v4 115 HP, I did a compression test and got 112 on 3 and 85 on 1. My mechanic said i should try ring free. so I bought a bottle of ring free, it says 2 oz per gallon. My question is should i mix the 12oz to 24 gallons and run the boat thru the 24 gallons or should i add 2 oz to 1 gallon and run the boat for that gallon only, the motor sat for 2 years and It does run/idle nice. or should i just run the motor and see if it clears up. Your thought?<br /><br />Thanks again. i know I can always get an honest answer here!

 

[ob]

Re: Sticky rings??

I wouldn't do either.Get yourself some OMC engine tuner and follow the cans instructions for decarb and see if it improves your condition.There is an injection fitting on your engines primer solenoid valve.Bare in mind that if the low compression on that one cylinder is due to a lean carb condition(scored cylijnder) that it will only get worse.Did you mechanic look closely at the condition of all of the sparkplugs and determine them to look the same,in an attempt to rule out a possible lean carb issue?<br /><br />You can also target just that one cylinder with the engine tuner by removing the sparkplug and distributing the product around the edge of the piston near TDC and letting set for several hours before running.

 

[Hotrods]

Re: Sticky rings??

I will do that. And he said everythink looked fine. but you do see im coming here for real info.

 

[Hotrods]

Re: Sticky rings??

Ok, Did the decarb thing as directed, did throw some in the Top right cylinder also and let it sit over night. Ran boat As directed....no change in compression. Motor ran nice not a sputter or stutter, was able to plain off @ 3000RPM. WOT got me 5000RPM @ 33 KNOTS. This is the first run for this boat for me (19' CC. 7'6 beam with 30"gunwales) 2 passengers, 20 gallons gas.. OK My questions are <br /><br />what do you think I should do about the 75 PSI in that cylinder. (yes it is 75 not 85)<br />And<br /><br />Does the rpm @ wot sound right for this size boat, is it propped right. Prop #'s read 18x19 <br /><br />I did get a nice calm speed @ 3800 RPM and really don’t plan on taking her over that unless im trying to out run a storm.. Your thoughts?

 

[ezeke]

Re: Sticky rings??

I think that it would be well worth the time to buy a head gasket and pull that cylinder head so that you can personally observe the condition of the cylinder.

 

[wayne h]

Re: Sticky rings??

your sure your compression gauge is accurate ? i know it sounds funny but it might be off i would get or borrow another and try it again just to see. sometimes u have to decarb a few times i think they call for a can per cylinder i know that sounds like alot. i use 2 cans on my little 9.5s 1 of them only had 58 - 60 psi but when i was done with 2 cans letting it sit over night and taking her out on the water the next day the compression when to 78 - 82

 

[OBJ]

Re: Sticky rings??

Hotrod....if your getting the same compressions after decarb, I wouldn't think the compression gage is at fault. (No offense ment Wayne)<br /><br />I would pull the head on the cylinder bank and take a gander. You might be seeing a wiped cylinder usually caused by a lean condition. Running it don't do it any good. Or in a best case senario, could be a blown head gasket.<br /><br />At least you'll know if you got a problem with the hole.<br /><br />Keep us posted...Thanks.

 

[Hotrods]

Re: Sticky rings??

OK...off will come the head and i'll have a look.<br />Would hate to blow her up while off shore, how does my rpm amd wot/prop size sound to you guys though?

 

[OBJ]

Re: Sticky rings??

Sounds to me like you could stand a little more rpm. Can't remember right off the top of what's left of my brain, but I think the operating range on the engine is something closer to 5500rpm. Maybe one of the other guys will get us straight here.

 

[G DANE]

Re: Sticky rings??

Your prop must be a 13x19, 18 cant sit on that. You shoud have a 13 1/4 or 13 3/4 x 17 i think, or maybe it could reach more rpm when the fourth cylinder was in better shape. I would do as OBJ suggests.

 

[BillP]

Re: Sticky rings??

It could be your decarb didn't work. I don't know about any other brand decarb than OMC Tuner...but it HAS to be used with a warm engine to get the crud out. Doing it with a cold motor isn't even close. If the motor doesn't need decarbing you won't see a change in performance either.

 

[Hotrods]

Re: Sticky rings??

I did look in at the piston and i do see black, like carbon, the plug is dark and a tad oilly I ran the engine in a tank @ 2300 rpm spraying 2/3 can slowly into carbs, but when it came time to load it up and stall the motor..no matter how much i sprayed it in i couldn't make it stall? so i shut it down and srayed the remaining into the plug hole. Hummm.. I think im gunna try the wd40 spayed on the head castget and see if the RPM raise, showing me a bad head gasket, it does look pretty bad....

 

[reload]

Re: Sticky rings??

hotrod try pulling the plug on that cylinder and squirting in some heavy oil such as gear oil. Retest the compression, if this helped that rings are most likely the culprit. There is stuff called Metifin (sp) b from a company called Magnus. Squirt it in the cylinder and spin it a few times then squirt in some more, let it sit over nite. If there is a carbon problem this will cure it.<br /><br />Paul

 

[Hotrods]

Re: Sticky rings??

I will do that also, I gotta Thank You all for all your help.

 

[alcan]

Re: Sticky rings??

Hi Hotrod<br />Bottom line, either the decarb juice worked or it didn't. In this case it did not. The reason it did not is because there is a bigger problem. Pumping gear oil into that cyl will only make a mess of your exhaust and fill your compression gauge with oil. Hec you would be able to get any reading you want. Spraying wd40 on the head gasket joint won't tell you anything either, just waste oil and make a mess. You can monkey around with this as long as it makes you feel good. If you want it fixed, pull that head off and see what the problem is.

 

[Hotrods]

Re: Sticky rings??

Could someone explain what I may find when I remove the head and what I will need to do with what I find. I would like to get the remainder of the summer out of the motor, then repair in the winter. I do plan on checking Compression after every trip

 

[ledgefinder]

Re: Sticky rings??

If the decarb didn't improve things, you should pull the head. It's not a big deal (job) on those two strokes. You will need a new head gasket ($15) and a torque wrench to reassemble things.<br /><br />When you get the head off, you may see the piston top and cylinder walls looking fine (no scoring/scratches in the walls, no melting or pitting on the piston top). In that case, good, it's probably just a leaky/loosely torqued head gasket, button it back up & retest compression. <br /><br />Alternately, you may see broken pieces out of the top of the piston, so that you can see sections of the top ring. In that case, not very good at all. It's unsafe to run the motor further. It may (probably will) fail catastrophically, further damaging the cylinder wall and likely trashing the block & crank. At that point, the motor is no longer even an economically-feasible rebuild prospect.<br /><br />Lastly, you may see scored cylinder walls and/or some melting of the piston top (compare the 'bar' on the piston top with the that on the other cylinder), without chunks missing out of the top of the top ring groove. At this point, the situation is uncertain. It may be possible, in a pinch, to continue running the motor for the summer. You will do some further damage to it (make the scoring worse), but probably not much. For one thing, maybe 25% of the older outboards out there are running around with a scored cylinder wall. HOWEVER, if you go that route you need to be SURE you don't still have the problem that has caused the scoring in the first place. Most likely cause is a dirty carb jet - dirty carbs run lean, and lean two-strokes heat up. It's not enough to clean the outside of the carb (obviously), you'll need to disassemble both carbs and clean out all the passageways, particularly the main jets. A can of spray carb cleaner with the plastic hose is great for doing this. If the piston top is melt pitted, you'll want to do some extra tuning to lower the operating temperature in that cylinder. The best thing to do is run a richer (bigger) main jet on that cylinder. Retarding the WOT timing 5 degrees may help as well. Both mean your're running less efficiently, and fouling the air more, but as a measure to get through the season, it's maybe acceptable.<br /><br />I bet you've got an in-boat fuel tank that had old/dirty gas in it, and never got cleaned. I hate 'em. I give people a 30day refund offer when I sell used engines, but NOT to someone with an in-boat fuel tank

 

[alanR1]

Re: Sticky rings??

I had a similar problem in my 82' 90hp johnson, it sat for a few years and got frozen, unfroze it and got it running, did a decarb and compression was good and in range, the first time out it burnt up the starboard top piston, it melted the top of the piston and pitted the head a bit. The is a tiny scratch on the lower half of the cylinder, i am going to remove the piston and hone the cylinder and try and put in a new piston and rings and give it a shot. You might consider doing the same, you can pull the piston by taking off the intake manifold and disconnecting the rod from the inside. If you do this make sure the cylinder is checked out for scrapes and such, rebuild you carbs as well and check all of your vaccum lines for leaks.

 

[Hotrods]

Re: Sticky rings??

Well thanks again, I am convinced to pull the head, i will do it this weekend please check back for my findings, And she is running a new aluminum tank.<br /><br />I will take pic's and post them for you also. Thank You all again for your time in this.

 

[Hotrods]

Re: Sticky rings??

OK...I pulled the head. Not happy........<br />The top right side of the piston (Top right V4) is pitted and has lost some metel pieces, the edge is damaged but not hitting the wall. there is a groove in the cyl wall at the top about a 1/2" long and it will click your finger nail. the head looks like the top of the piston where it was hitting. i did pull to small pieces of metel out that looks like those pieces caused all the damage. The piston is fine where the cly is scorn. Im thinking the to pieces came from the ring. and were getting smashed on part of the head and piston.. It seems that piston has some sloppy play back and forth<br /><br />...OK....now what)