Inline 6cyl. won't run past 1800rpm

[kirchm1]

I have an '84 90hp merc. Inline 6 cylinder that won't run past 1800rpm in the water. It's firing on all 6 cylinders, has good compression and the carbs are opening up all the way. When the motor is tilted up past the trim stage, gas leaks out of all three carbs. What should I do?<br /><br />Thanks for any help on this one.

 

[achris]

Re: Inline 6cyl. won't run past 1800rpm

Mike,<br /><br />Welcome to iBoats<br /><br />Check that the timing is advancing correctly and to the maximum.<br /><br />Another possiblity is a high speed stator failure. Does it rev ok out of the water, on muffs?<br /><br />Chris............

 

[gewf631]

Re: Inline 6cyl. won't run past 1800rpm

Have you tried pumping the bulb? If it makes things worse, it's probably the fuel pump diaphram.<br /><br />If it makes things better, you've got a fuel starvation problem that could be your tank-vent, your filter, bad hoses, etc.

 

[kirchm1]

Re: Inline 6cyl. won't run past 1800rpm

It revs up fine when hooked to muffs. I will check the timing. I was wondering if it could be a problem with the fuel delivery (ie. fuel pump).<br /><br />Thanks for the quick replies

 

[gewf631]

Re: Inline 6cyl. won't run past 1800rpm

Mike,<br /> I have almost the same problem with my mid-80's 115HP, only that it revs up fine in the water (under throttle only), but kick it in gear and she'll bog. This first started as an intermittant problem, but got worse the more I used-it (all in one outing).<br /> The new diaphram-kit was about $10, and should be readily available at your local dealer. If not (or if you can wait a few days), iBoats carries them - but you might end-up higher due to freight, so pick-up a new prop while your at it

 

[ZmOz]

Re: Inline 6cyl. won't run past 1800rpm

I had the same problem with my 1500 last year when I bought it...ran a BUNCH of seafoam and deep creep through it and the problem went away.