1994 90hp dies over 2000rpm

[jrnew]

ran boat for the first time. Ran great for 20 min @ 4k-5k rpm.Idled for 10 min thenwould die over 2k. would start and run but not over 2k. After trying 3-4 times ran great till I would slow. The promblem would start over. Ithink I should rebuild the fuel pump.Or?

 

[pnwboat]

Re: 1994 90hp dies over 2000rpm

Kind of sounds like a fuel delivery problem.

1. Make sure your gas tank vent is open and not plugged. You can test by loosening your gas cap to allow air to enter the tank. As the fuel pump sucks gas out of the tank, it will create a vacuum in the tank if the vent is plugged. The higher the vacuum, the harder it is for the fuel pump to pump fuel to the carbs.

2. There may be some debris in the tank or fuel line that may be restricting the flow of fuel.

3. If the above mentioned items check out OK, try changing the fuel pump diaphragm.

 

[mrwglo]

Re: 1994 90hp dies over 2000rpm

I had this same problem with my 1994 90hp. I, however, wasn't running 4-5 K rpm at the time, I was much less. I opened the head to find detonated pistons and subsequently bad rings. A rebuild from Frank (he's lurking somewhere here I'm sure) put it all in order and I was trouble free all year. This motor seems to dirty plugs a lot, you might check to see their condition as even a little dirty causes tough starting and tough "warm engine" low rpm running. Good luck!

 

[erikpn]

Re: 1994 90hp dies over 2000rpm

Assuming good compression, disconnect the rectifier and retest. Pull spark plugs and look for a clue. Lots of fouling? Correct type spark plugs? Check timing. Check ignition coils with a multimeter. That's the free stuff to check.

Buy a vacuum gauge and some clear line. Proceed to test fuel system.