what went wrong?

[dreamchaser]

back on feb 25 while running 20 miles back to the dock I lost full power 5700 5900rpm...it would only run just above idle speed, 2500rpm for about 3 miles ....then i throttled up she came back to my surprise .all seemed well ...got her home... it ran fine on the hose , last week took it out for a trial run ....within 5 min it lost power again. To make along story short.... I...checked compression. It lost all in cylinder no 3 . I took it apart today......the ring was missing from the top land and on the exhaust side a 1 inch long half moon about a 1/8 of an inch thick was gone from the top of the piston edge not to mention all the scoring down the whole side of the pistion and cylinder ........was this just a case of old age ? I always made sure my oil mixes where on the plenty ......what would cause this engine failure ?thks :'(

 

[dreamchaser]

Re: what went wrong?

sorry forgot to mention my motor is a 1983 115 evinrude 2 stroke

 

[Chinewalker]

Re: what went wrong?

Hi DreamChaser,
Did you ever do a decarbon? What happens is that over time carbon can build up in the ring grooves and "jack" the rings outwards into the cylinder wall. Eventually the ring sticks on an intake or exhaust port and breaks the piston, gouges the cylinder wall, and generally causes havoc.
A decarbon with something like SeaFoam or BRP Engine Tuner can loosen up and blow out built up carbon. I put a lot of hours on my motors and try to run some Engine Tuner through them once a season...
- Scott

 

[tashasdaddy]

Re: what went wrong?

i don't know if the 83 had a safe mode on not. but sounds like it got hot, and shut down to the safe mode, then cooled off, and went back to normal mode, then got hot again. all things together you have the results.

 

[F_R]

Re: what went wrong?

Carboned up. Or running lean on that cylinder because of a problem with the carb that feeds that one.

 

[dreamchaser]

Re: what went wrong?

thks guys for ur input .......After lookin closely at the ring lands , there is a lot of build up ...I did do a decarb with seafoam last fall b4 i winterized it ..but who knows b4 that . I purchased this motor last aug ......the carbs where taken apart , cleaned after soakin and cleaned out all the orifices ,,,,, and T D when it did loss power i pulled the cover off to check for heat .there wasnt any ...live and learn ......