Problem with 88 Evinrude 100 xp

Joined
May 21, 2017
Messages
10
Hello all,
So quite some time ago i inherited my grandfathers 17.5" Hydra-sport VS 120 bass boat before he passed and this boat has a lot of sentimental value, He was my bass tournament partner whom i miss dearly. Now the motor is an 88 Evinrude 100 XP which ran great before now. So yesterday me and a buddy of mine went on a fishing trip and we ran into a problem a couple hours in and far from the ramp. I was running the boat about 70% of WOT and it bogged down and stalled hard. I've always ran the motor a little richer than 50:1 do to the age. I would rather deal with fowled plugs and know the motors internals are getting what it needs. Now being the person I am, I'm always prepared for worst case scenario and had my tool bag! Which became a real blessing yesterday and got us home safely! After the motor stalled i tried restarting it and it would hesitate to start, spit and sputter and finally bog out again. So i raised the motor and pulled the plugs to see if maybe they have fowled. This is were i found a serious issue, on the 3rd plug i pulled i actually found that the gap on the plug was smashed completely shut... Talk about an "oh F$%^" moment... So i opened the gap back up the best i could and put the plug back in. Sure enough the motor fires up and doesn't stall, sputter or bog. Talk about a tough motor!!. But anyways it was enough to get the boat to plain and keep a good slow steady pace, running maybe 20% of WOT back to the ramp. and we made it! Talk about being relieved!! What a day that was and a nightmare it could've been.. Sorry for the rant for those who may not be interested but i figured the scenario would help understand the problem a little better. My guess is that a rod bearing went out causing the piston to smack the plug shut at higher RPMs. Maybe i'm wrong?.. Now i can't afford to just go out and buy a new motor for this boat and call it a day.. wish i could!. Maybe an old used one if the price is right but from what i can tell, it's still a pretty penny for a 100hp old and used! I've rebuilt old chevy motors and currently rebuilding a hemi motor, but a boat motor would be an all new playing field. Especially a 2 stroke motor.. Would i be in over my head trying to rebuild this motor? and be better off trying to replace the power head? Which may be an option. Any suggestions and opinions would be great!
 

flyingscott

Fleet Admiral
Joined
Apr 8, 2014
Messages
7,991
Pull the head off it is probably a broken ring the crossflows are known for that. You could absolutely rebuild it yourself. WSM makes really good rebuild kits at a reasonable price. Replace all 4 pistons if you got the rebuild route.
 

jbuote

Lieutenant Junior Grade
Joined
Aug 17, 2016
Messages
1,001
Can't speak to the possible issues with it, but in regards to being over your head if you choose to rebuild?
​Based on what you've said, NO.. I don't think you'd be over your head.. Probably easier to a degree than what you've already done with Chevy and now a Hemi...
​No valve train on a 2-stroke.. It's a simpler engine..

​A good service manual and the right parts, I have no doubt you could do it if you chose to.

​So that's the only question I'm answering.. The rest I'll leave to the real experts here.. LOL
 
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