2001 Mercury outboard 90hp 4-stroke

[jmorgan]

I am rather a boating/engine novice so I thought I'd see if I could get some help/advice from this site.

I have a 2001 Mercury 90ph 4-stroke outboard and it's been acting funky - meaning (1) just after starting, it doesn't run with the throttle in the idle position - I have to push the throttle forward a bit to let it run or throw it into gear with advance throttle to move forward/backward, and (2) while in use in low rpm it stutters and pops every now and then with slow, stuttered acceleration. When up around 4,000 rpm it seems to run smooth - doesn't quit.

Any suggestions? Could it be fouled plugs? I appreciate any advice anybody can lend me...

 

[Silvertip]

Re: 2001 Mercury outboard 90hp 4-stroke

Could it be fouled plugs???? Take them out and look! But probably not. You didn't say if this engine was carbed or FI but if its carbed, it may be due for carburetor cleaning. I assume you have fresh fuel in the tank.

 

[rickdb1boat]

Re: 2001 Mercury outboard 90hp 4-stroke

Those older Merc. carbed 4-strokes were very picky about using good, clean fuel. The carbs have very small passages that clogged easily if untreated fuel or old fuel was used or allowed to sit in the carbs for any period. It could be other things too, but if it sat at all for very long, I'd be cleaning the carbs out...