90hp force won't get above 4,000 rpms

[justink51]

hello,
i have a 1998 90hp force.the boat sat for 2 years. I bought the boat from a friend and have been on it when it was running good. Be fore i started the boat i drained the old gas by disconecting the fuel line after the priming bulb and squeezing the priming bulb until no more gas came out(about 20 gallons). Next i filled the tank with new gas, changed the filter, plugs, impellor, and lower unit oil. I took the boat out for a test run and it wouldn't go above 4,000 rpms except every once in a while it would rev up to 5500 rpms and then go back down to 4000 rpms after a few seconds.WHEN THE RPMS HIT 5500 IT FELT LIKE IT DID WHEN I WAS ON THE BOAT WHEN IT WAS RUNNING GOOD, I then took the boat to a mechanic who cleaned out the carbs. the carb cleaning didn't help. I am thinking that i need a fuel pump (but am not sure). Is there any way to test the fuel pump or do i just change it and hope for the best. ANY IDEAS ON WHAT THE CAUSE OF MY PROBLEM IS???????
THANK YOU FOR ANY HELP YOU CAN GIVE ME.
THANK YOU, JUSTIN

 

[roscoe]

Re: 90hp force won't get above 4,000 rpms

Have you checked for a consistent strong spark on all 3 plugs? Sounds like a cylinder is cutting out on you. But 4000 rpm out of 3 cylinders is pretty high, I would expect 2800-3000 out of just 2 cylinders.

Symptoms are not common for a bad fuel pump, but you can rebuild it for $17 in parts, and 30 minutes of your time. Order it from Mercury, and the instructions are included.

 

[snorkysnork]

Re: 90hp force won't get above 4,000 rpms

My 75 hp was doing the same thing. took awhile to find it... not to mention
$$. Ended up being the reed plate. Was new to me as i've never heard of
the thing.

But... after replacing.. it's running better than ever.

I'm not a mech. so you'll have to do some digging around here or other
forums for info on the reed plate. It's somewhere behind the carb and intake.

oh.. a buddy of mind asked me if i used the fiberglass version..
i didn't . he mentioned that you'd get better performance and if they
ever cracked or broke again the damage would be minimal.

good luck