Logo
FULL SITE MENU

1989 Evinrude 100xp falls flat at WOT

A

ajbradshaw

New member
Hello everyone, new to the forum and appreciate any help I can get. I’ve got a 1989 Evinrude 100xp E100STLCEM. It is running really rough and can’t get to full power at WOT. So far I’ve replaced the fuel line including primer bulb, anti siphon valve, fuel tank pick up, fuel filter, spark plugs. I’m leaning towards gummed up carbs as being the issue but I just discovered a crack in the red maintenance valve and fuel was leaking out of it last time I tried to start it. Could this be why the engine is running poorly at higher speeds due to air getting into the carbs? Thanks in advance for any advice.
 
Was able to do a compression test today. Just FYI, I wasn’t able to warm it up due to the fuel leak and the motor not wanting to start. Readings are top left:94 top right: 114 bottom left 110 bottom right 125.
 
Motor needs to come apart.----I know I am blunt.------Pull the head off the cylinder with 94 PSI.----I do not believe you will like what you will see.-----Lucky you if it is a head gasket issue.----But I think it is the very , very common piston ring failure.----Worth rebuilding this 115 HP if you can do the work yourself.
 
I saw on a video that you’re supposed to open the throttle a bit and have the engine warmed up. Do you think that had an effect on the numbers I got?
 
I ended up pulling the head off and there was damage to the cylinder with the lower compression. Would you suggest just buying a new power head?

Racerone, I saw you mention in a similar post about having a few of these v4 crossflow power heads laying around. I’d be interested in buying one off of you if it could be shipped relatively easily if you had a price in mind.
 
I didn’t find any evidence aside from the marks that it left on the piston head and cylinder head cover. I’m located in Kansas City. Would be willing to drive up to 8 hours if need be to save some money on shipping but am also willing to pay for the shipping in order to save some in the long run.
 
Sorry ----Too far away to help on this one.----Not easy to find a shop willing to rebuild these anymore.----Try----Crowley Marine ---See if they have rebuilt units in stock.
 
Back
Top