1989 90 hp problem

[brece1]

i have a 1989 90 hp just purchased boat, new plugs, i removed carbs and cleaned them out, made sure jets where clear. i had bad fuel and dumped tank, fresh fuel w/stabil, new 10 mic. filter, motor runs great for about 10 miles, 5300-5400 rpm then i am getting a miss and loose power. back off throttle, motor will smooth out but can only gett 4500 rpm, then misses again, also once this happens the idle
is VERY rough.

do you think trash in carb? or tempature related? or something electrical? is there temp. sensor that would cause this ?

 

[99yam40]

Re: 1989 90 hp problem

Sounds like trash from tank,lines, primer bulb, and fuel pump hit carbs again and they need to be cleaned

 

[brece1]

Re: 1989 90 hp problem

thank you i will try that.

 

[yamatech43]

Re: 1989 90 hp problem

You may have to do an actual proper cleaning of the carbs...that is take ALL the way apart and SOAK in carb cleaner....but EPA has done away with carb cleaner as existed for decades and now you have to use something like Berryman's (Walmart, NAPA) and you can soak all night(and will have to) without hurting the aluminum....if you soaked all night with old stuff....the carbs would start dissolving....10 hrs in new stuff is safe. I like to agitate the bucket once after half a soak to help. And if the lines are old i would replace them...89 a looong time ago....small pieces will be separating inside and flowing to carbs.

 

[brece1]

Re: 1989 90 hp problem

got it that is what is happening right now. i hav replaced all fuel lines, and disassembled the carbs and soak. the 2 of the small jets had some thing in them (soft ) when i ran a wire thru theu them no resistance.