yamaha 1990 90horse fuel problem

[badger54]

I have a 1990 yamaha 90 that will not keep fuel prime . this problem has gotten worse at first it would prime with primer ball getting hard and then run at lower rpm then quickly drain ball when getting on plane? would just prime ball up and would run ! but over time this problem has gotten to the point were primer runs dry after idle speed for a coulple of min?
replaced new lines and anti siphen valve also new primer ball and fuel/water filter now worse than before seems like some sort of vacum being created as primer ball callapses and is drawn tight? released the fuel cap and tried pumping but still nothing? any ideas?

 

[robert graham]

Re: yamaha 1990 90horse fuel problem

It's a pretty good bet you've got a fuel restriction somewhere, fuel tank pick-up, vent, fittings, etc. Put your fuel line in a seperate container of fuel like a gallon jug or something, prime it up, see if it'll run like that. Normally,primer bulb should be between tank and fuel/water seperater. good luck and let us know what you find.

 

[badger54]

Re: yamaha 1990 90horse fuel problem

tried the running it on an external tank trick and it seemed to run well ! so im guessing ive got trouble with the fuel pick up line in tank?
might be clogged ? I read were there is baffles inside some tanks(styrofoam) that the newer fuel can errode? anyway thats were im going to look next .