9.8 merc 1985 problems

Rendrick

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May 20, 2009
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3
Hello all hope u guys can help. So it goes like this took motor out for first trip of the yaer worked fine next day wont rev up but idles fine now only idles for a minute or 2 .I have totally rebuilt carb changed plugs and new fuel source. no change it idles ok but when u try to rev it bogs and sounds like it misses.in neutral or forward. i have comp tested cylinders 120psi each . tested spark good. im quite mechanically inclined but this has me stumped. it also appears that i have water spraying out of upper exhaust . dont recall seeing this before tell tale working well. any suggestion would be much apreciated:)
 

CharlieB

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Joined
Apr 10, 2007
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5,617
Re: 9.8 merc 1985 problems

Sounds like you've covered most of the fuel system, but what about the fuel pump, primer bulb and hoses?

A weak pump, or air leaking INTO an old cracked hose or loose fitting and it won't have enough fuel to make any power.

Water out the exhaust vent above the water line is normal, you just didn't notice it before.
 

Rendrick

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May 20, 2009
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Re: 9.8 merc 1985 problems

rebuild kit for fuel pump came with carb kit for 75$:mad:lol ive tested fuel lines and primer bulb with a vacum gauge no leakdown after 5 min im tearing it down now exhaust seem full of goo and carbon going clean it fron piston to outlet fingers crossed:) then try it again
 

CharlieB

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Apr 10, 2007
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5,617
Re: 9.8 merc 1985 problems

The idle mixture must be fat enough for the motor to take throttle and accelerate, too lean and it will bog.

Usually set idle mix to best idle IN gear, IN the water, PLUS @ 1/8 turn fatter. Some slightly more or less.
 

Rendrick

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Joined
May 20, 2009
Messages
3
Re: 9.8 merc 1985 problems

:Dgot it figured out exhaust in lower leg was plugged with weed and gunk cleaned it out and she purrs like a kitten once again. Apreciate the help guys and i look forward to learning more from u guys and the site> i got my eyes on a 1979 silverline with a 115 evinrude she been parked a coupl years so im sure shell need some tuning. Thanxs again:)
 
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