Need with my 1986 90 HP evinrude

DLMcBeath

Cadet
Joined
May 6, 2012
Messages
9
I took my boat out today and it ran great at first. At full throtle I was running about 5500 rpm, all of a sudden it drops to about 3000 rpm and then back to 5500 rpm over and over. If I would throtle back to about 4000 rpm it ran fine. Seems like a fuel problem. I swapped fuel tanks in case of water in the tank, I thought about the fuel filter. Any suggestions?
 

Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: Need with my 1986 90 HP evinrude

High speed jet plugged or restricted?
Loosing spark on a cylinder?
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: Need with my 1986 90 HP evinrude

If you have someone constantly prime the fuel hose bulb will the engine run ok at WOT? If it does, probably a weak fuel pump.
 
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