yamaha 150 87 problem help

[outcast fishing team]

im having a problem with my 150 yamaha when at cruising speeds it tends to cut back then go again it sounds fine just looses power could this be a fuel problem or something else the motor sounds fine what should the fuel pressure be it almost sounds like it goes into limp mode but!!!!!!!!

[VectorPat]

If it is going into a limp mode or RPM reduction from oil or overheat it will stay there at around 2200 rpm until you throttle it back and let it cool down or fill with oil. If it continues to get worse the further you push the thottle it sounds like fuel. Check your carbs, if the boat has been sitting up for awhile they may have some varnish build up in them.. Your fuel pressure should be around 3-4 psi or higher. Also check your fuel vacuum it should be less than 4in at full throttle. If it higher you have a restriction somewhere..

[Ray Neudecker]

Definitely sounds like a fuel restriction. Disassemble and clean carbs. Use new gaskets for the bowls. Time to replace (not rebuild) fuel pumps. Remove fuel disconnect and run hose straight to the filter. Be sure fuel lines are fresh including bulb.