toybreaker

I have a 2001 90 Mercury four stroke, made by Yamaha. I posted on here once before about cleaning the carbs. I balanced the carbs with new gauges. This is the fourth cleaning this year. I thought I wasn't getting them clean. Last time I let them set in Berryman's for a week. blew them out with compressed air. I'm concerned the needle and seat aren't seating proper. If I pump the bulb as hard as I can gas leaks out of top carb. ( very little?) It fires on all cylinders but seems weak. Given up that it's carb's?? I'm thinking it could be the stator or a coil breaking down. This is what it is doing, It's hard starting, idles ruff, comes up on plain, goes 100 yds and dies. After that just idles ruff and bogs down when trying to accelerate. Looks like I need to make a puller to get the flywheel off. Any surprises I need to know about? Youtubed an ohms test for stator.

Check fuel pressure. compression and leakdown test.

I checked compression, 3 cylinders at 150, the bottom cylinder was 60lbs.

Do have to rebuild the whole engine or can just one cylinder be rebuilt? Should it run as is or do you think carbs are still an issue?
How much should I expect to pay a professional to fix?

toybreaker said:

I checked compression, 3 cylinders at 150, the bottom cylinder was 60lbs.
?

Click to expand...

That's your problem. If you can, get a camera in that bottom cylinder to see what damage is done. That's not a cheap fix, its a complete tear down of the power head.