1986 50 ELJ not developing RPM

[merrillrich]

Help!

My 50 ELJ will not develop RPM’s over 3000 I have gawn through the fuel system completely including carb rebuild, new fuel pump, new gas tank with hose, filter cleaning, and new plugs. I started out chasing an idle and rpm loss problem. Now idling good with no loss of RPM but wont go over 3000.

[Ken]

merrill,
I would check the linkage on the carbs and make sure the fuel control handle is opening up the carbs all the way.
If no problem with the carb linkage, then I would check compression.
Good luck,
Ken K

[merrillrich]

Ken,

The linkage is good (first thing I looked at). The motor ran at higher than 3000 before the carb rebuild. I will have to locate a compression tester. Could it be ignition? I grounded the plugs and got spark for all. Do you know if coils get weak or do they just go out all to gather.

Thanks for the help
Merrill

[Ken]

merrill,
I would not think that the coils would get weak - more likely to go out all together.
Seems curious that the problem did not show up until you had the carbs rebuilt. I'm probably grasping at straws here, but check the choke butterfly valve and make sure it is not partially closed - maybe linkage needs adjusting.
Good luck,
Ken K

[merrillrich]

Ken,

I found the problem. No compression on the top cylinder. Can complete rebuild kits be found out there?

Merrill

[Ken]

Merrill,
Go to www.boats.net (sponsor of this forum) and look up your model outboard and see what service kits are available.
If your motor has not been decarbonized, say in the last five years, then I would try that first - you may have stuck rings due to carbon buidup. Scroll down thru the posts - I have the procedure using "Seafoam" listed several times.
Also, one of the members used something called
"PB-Blaster" to free some stuck rings - but be careful using that stuff.
You may get lucky and the above work for you - if not, then ring replacement is probably in order.
Good luck,
Ken K

[merrillrich]

Ken,

I have zero compression. As if the piston is not moving at all. I would think I would get some compression even if the rings were stuck. I am thinking I have a broken rod or cap. There are no holes in the block so that’s a good sign. When I get more time to go out there and do some more testing I will have a better idea as to what exactly happened.

I looked at the parts pages and didn’t see any kits. Maybe I’m looking in the wrong place.

Thanks,
Merrill

[merrillrich]

I found the problem, broken rings. I pulled the head and there were pits on the top of the piston and it was loose in the bore. Hopefully the scoring in the bore can be cleaned up.

Merrill

[Ken]

Merrill,
Glad you found the problem - may have to go to oversized rings or punch out cylinders and go with oversized pistons - I've never done this on an outboard motor - let us know what you do/have done - would like to get some feedback.
Also, you said the top of the piston was pitted? How deep are the holes?
Thanks,
Ken K

[merrillrich]

Ken,

The pitting on the top was more like small dents but the edges of the piston is sort of rolled over. I guess caused by bits of ring getting in the combustion chamber. Also found some dents or pits in the head that will have to be cleaned up. I plan to pull the power head this weekend and start the disassembly process. I have the Seloc repair manual, which has the whole process outlined in the power head section. My biggest concern is the scoring in the cylinder wall. Hopefully it can be salvaged at the machine shop. I will post results of my shade tree rebuild.

Merrill