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1983 115 No compression

K

kbliek

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Hi, I have a 1983 115 Evinrude that was spotless when I bought it few years ago. The compression when I bought the motor was around 140 or so on all cylinders. Last fall it would not idle properly but seemed to run out fine at top end. Idle got worse as the fall went on. I was going to do a carb rebuild but thought I would check the compression first. Now one cylinder has no compression and the other three are at around 90.

I have no idea on the common symptoms or problems with these motors so any thoughts would be appreciated very much. Thanks in advance.

Ken
 
Very common for these motors to have / suffer from broken piston rings.------------Next step is to remove the heads for an inspection.------------Causes may be as follows ---Wrong prop and motor not running at proper RPM.----------No thermostats and motor running too cold.-------Not allowing motor to warm before full throttle operation.--------High hrs and pistons too sloppy in the bore etc, etc.
 
That 1983 115hp Evinrude engine has a simply gasoline fuel pump and is designed to run on a 50/1 fuel/oil mixture.

It does not have a VRO mixture pump that automatically mixes the gasoline with the oil.

Is it possible that someone borrowed your rig that wasn't aware of this and ran the engine on just straight gasoline?
 
Thanks for all the help. I have been pretty diligent about letting the motor warm up before pushing it, even when it's hot in the summer. I seldom if ever run at full throttle. I did borrow the boat out once last summer so who knows what could have happened there, although I was pretty adamant that they add oil when gassing up. The entire motor including prop is factory.

Would a worn head gasket allow for the low compression on the other cylinders as well? I will be pulling the heads in the next day or two for inspection. If it is deeper than that (piston, rings, etc.), I do not think I want to go into it any further on my own. Not sure if it is worth spending big money on the old girl, but I really liked this motor. I have no idea what a job like this would cost.

Thanks again for all your help.
 
When properly rebuilt it will run like new again.-----------------Very good / strong motors.-----------Perhaps cheaper to own / operate and maintain than the newer 4 stroke and high tech motors.------If you have to pay a shop to do this work that is a totally different story.
 
No such thing as a worn head gasket, an engine overheat could possibly cause a head gasket to let go,you could pull spark plug and have the bad cylinder bore scoped for damage before removing cylinder head
 
Ok been a few days but I did find some time to take the head off. One cylinder wall is scored pretty bad. When I took a pic and sent it to a mechanic he thought it was beyond being able to bore it out. The pistons are extremely clean, no carbon build up or anything like that. The mechanic said he thought it looked like it was ran without oil which is probably what happened when I loaned it out last year. I've never tackled a rebuild project like this but am thinking about doing it myself. Does anyone know what year blocks will work for this 1983 and possibly where I could find one or am I better off just parting it out? Thanks for all your help!!
 
Really? I didn't know it was a sleeved engine. Where would a guy send it to get done? I am from NW Iowa (Idiots Out Wondering Around :D) Finally no I never said anything to the guy, I can't say for sure that's what happened and I think he would feel horrible if I mentioned it to him. Thanks so much everyone.
 
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