Am I in need for new rings? or is it something else

Tarinazo

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Feb 18, 2019
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This past weekend while fishing, my outboard gave up on me (1979 15hp Johnson), at first, while running, I felt like the prop got tangled or hit something, the engine stuttered a bit so I turned it off, tilted the engine to check the prop, no visible damage, besides I was on 30+ feet of water.
Turned the engine on again on first pull, the engine ran but a bit sluggish, not like it should. I got to my fishing spot and turned the engine off. I fished there for some 40 minutes before I tried to run the engine again... nada!
When I pulled the cord, the engine made a whirring throaty sound for about 2 seconds. did this a few times so I took the cover off for further inspection, visibly nothing was out of place, pulled the cord a couple more times... same whirring sound on the last second of every pull. I then noticed that the pull was a bit lighter so I tirned the flywheel by hand to check for some compression rresistance... nada! the flywheel had little to none resistance while turning.
Ma de it bacj to shore with my trolling motor and decided to take the head off, rings where my first suspect. With the head off I noticed both piston ran in and out but made a sqeaky sound.

I'd like to note that I personally made made my premix (2.6 ounces per gallon), plus I always add a couple ounces of Sea Foam.
Water was coming out of the telltale all the time, no signs of overheat (already took care of that problem a couple months ago).
 

racerone

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Dec 28, 2013
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What do cylinder walls look like ?----Any close up pictures ?-----Wrapped a plastic bag around lower unit to cause overheat ?-----Water pump impeller will squeak too.
 

Tarinazo

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Feb 18, 2019
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Later today I'll upload a video, I hope the sqeaky sound is clear on that one.
Cylinder walls seem fine, to my surprise.
It was not an overheat situation, of that I'm sure.
 

F_R

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whirring sound on the last second of every pull. I then noticed that the pull was a bit lighter so I tirned the flywheel by hand to check for some compression rresistance... nada! the flywheel had little to none resistance while turning

Sounds to me like a loose flywheel and sheared key. Coasting to a stop after the pull.
 

Tarinazo

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Feb 18, 2019
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Mmmmmmmh, I'll take the flywheel off today after work, before that I'll take a video of that whirring sound on the las portion of the pull.
I guess I'm also in for a compression test before pulling the powerhead apart
 

Joe Reeves

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Feb 24, 2002
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I tried the flywheel by hand to check for some compression resistance... Nada! the flywheel had little to none resistance while turning.

On both cylinders?... If so, that would ring a bell with me as a blown head gasket between the cylinders. Perhaps you're not that lucky... BUT... it's worth a mention.
 

Tarinazo

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Feb 18, 2019
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We got a winner! F_R!
took off the fkywheel only to find out it had no key... looked carefully and found it resting beside the electronic parts. Judging by a visual inspection it seems nothing was harmed by the key hanging loose.
 

Tarinazo

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Feb 18, 2019
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Do you guys think it's still usable? I don't think I can find a stock part i Mexico by Sunday (fishing tournament... wish me luck)
 

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Tim Frank

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You MIGHT get away with re-using it, but if you don't it could be a disaster.....could wreck the groove in the crankshaft.
In fact, I'd say you have had more than a fair share of luck so far.

I have never seen a key come out like that...i.e. in apparently one piece. Not even sure how it could.

Did you have the flywheel off for some reason?
 

racerone

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Dec 28, 2013
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Usually it takes some brute force to take it out of the keyway.--------But put it back in with some sealant to hold it.----See if motor will run.
 

Tarinazo

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Feb 18, 2019
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How it got out in one piece? I have no clue, I guess it slipped somehow... although the flywheel came out with a bang when i pulled it out, so I guess it was somewhat tight.
Tha shaft is a bit greasy, black, sticky... I'll clean it, polish the key with a Dremel bit and put it back together using my Harbor Freight torque wrench (I knos it's not the best, but it's all I have).
 

Tarinazo

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Feb 18, 2019
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UPDATE: got everything in place, engine started on the second pull... it revved hard but slowly got to idle and stayed that way. The dufference now is that it's smoking more than usual and it's an eye-stinging smoke, not that common 2-stroke smoke that we all like (at least I do).
 

Tarinazo

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Feb 18, 2019
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I've been doing some reading and it seems to be water getting into the combustion chamber. I did take off the head to inspect for broken rings, the headgasket is fairly new from an overheat I had a few months before BUT I didn't torque the bolts down to spec... so
 

54bobby

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Dec 12, 2010
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when my 69 25hp evinrude had water in the combustion chamber it was a perforated inner exhaust cover plate. not sure on your model but had to remove the power head on the 25.
 

Tarinazo

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Feb 18, 2019
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Yesterday I ran it again and noticed more water sputtering out the upper exhaust, plus water coming out in a short stream from the watchamacallit lower shaft grommet... I'll post a pic
 

Tarinazo

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Feb 18, 2019
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Took my boat for a spin this past weekend, the engine handled quite well, always starts on the first pull no matter how cold the engine is... the only thing I noticed different is top speed. This outboard is fairly new to me and I remember it being faster on the first runs (same boat, same gear), at WOT it gives me some speed bursts, like it wants to speed up every 5 to 10 seconds.
 
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