1991 90 hp Force power loss

[davekat1400]

My '91 90hp starts and runs well but after 5 or 10 minutes at high RPMs it starts to run rough and loses power. It falls off to idle speed and continues to run. I have replaced the fuel pump, checked the lines for restrictions, and checked the bowls and jets. Plugs look good but I am starting to think it may be electrical. It pumps plenty of water so I don't think it's overheating (no bells or buzzers go off). I read about some stators having problems at running temperatures. Is this a common problem with my type of motor? Please help! Thanks, Dave

 

[speeddemon1452]

Re: 1991 90 hp Force power loss

check the tank vent might be cloged not letting air in fuel tank cousing it to starve it from getting gas becouse of vacume in the tank

 

[t.martin]

Re: 1991 90 hp Force power loss

your coils could be breaking down.

 

[Oldsaltydog]

Re: 1991 90 hp Force power loss

You could check with themarinedoctor.com for advice from experts.

 

[eurolarva]

Re: 1991 90 hp Force power loss

Does your motor have red or a black stator. If it were your coils it would seem strange that all three would go on the blink at the same time. The black stators were a problem for mercury. I am not sure if this applies to your motor but it was the high speed part of the stator that was crapping out on the black ones.

 

[flips]

Re: 1991 90 hp Force power loss

My merc 80 hp done the same things years ago,Ichanged and cleaned all the fuel bits and pieces.Turned out to be stator ,mine ran for about 3 min then would die.

 

[davekat1400]

Re: 1991 90 hp Force power loss

Originally posted by speeddemon1452:<br /> check the tank vent might be cloged not letting air in fuel tank cousing it to starve it from getting gas becouse of vacume in the tank

Thanks speeddemon, no problem with fuel system or vent. Sure does act like it though!

 

[davekat1400]

Re: 1991 90 hp Force power loss

Originally posted by eurolarva:<br /> Does your motor have red or a black stator. If it were your coils it would seem strange that all three would go on the blink at the same time. The black stators were a problem for mercury. I am not sure if this applies to your motor but it was the high speed part of the stator that was crapping out on the black ones.

Thanks eurolarvae, I'm going to check it out this weekend. Sounds like you may have nailed it. And thanks to every one who responded, I appreciate it very much!