Have a motor issue and need some help

[jasonak]

I have a '88 90hp outboard. The motor idles like a dream..when I go to apply throttle it opens up great for about 8-10 seconds then dies down to about 1/4 throttle. Ive put a new fuel bulb..line.. tank fittings..new fuel pump...but have no idea what may be the cause.. any help would be greatly appreciated!!

[jb123]

sounds like a restriction, could be tank, vent etc, hook up an auxillary tank, hose and ball to motor filter and try.

check ball when it dies down to see if it is flattening

[bill5280]

I have a '88 90hp outboard. The motor idles like a dream..when I go to apply throttle it opens up great for about 8-10 seconds then dies down to about 1/4 throttle. Ive put a new fuel bulb..line.. tank fittings..new fuel pump...but have no idea what may be the cause.. any help would be greatly appreciated!!

Jason, If problem persists after fuel is checked out make sure all vacuum and oil lines are not damaged or pinched also check temp sensor and oil sensor if you do not premix. If one of these are bad will shut engine down to idle. Coils may also be the problem under a load, you could try disconnecting each one (one) at a time then try to see if there is any difference! Could also be high speed jet(s) if this is a carb model. Make sure this jet and bottom of bowl is clean!
Hope this helps!!
Bill

[robert graham]

Maybe drain each carb onto a clean white rag to see if you have water or debris in float chambers. Good Luck!

[jasonak]

Thanks so much for the input! I'll definately try each suggestion out next week..hopefully its just a a tank issue...

[BQUICK]

What I do is remove the carb drains then squeeze primer bulb to flush carbs. Amazing the junk that comes out. Better yet stick the end of your fuel hose in Seafoam and pump that thru the lines and carb.

[braq]

Hi,
Good running older motors are a glut on the market and obsolete ones are almost free. Saw an old chrysler with con***** box -a runner- for $150 in the white sheet last week. The ignition alone for that motor is $360. So your cheapest would get a running used merc 85 in the same vintage and hold yours for a spare parts motor.