Mercury 850 problems

M

MillerSVT

Cadet
Joined
Mar 13, 2010
Messages
26
Well I rebuilt the carbs on my Merc 850 outboard, now It'll turn over fine. Fires if I put gas in the cylinders but won't fire on its own. Primed it until there was gas coming out of the carbs. I did notice more seemed to be coming out of the top carb than the bottom one. I'm stumped.

I did do a compression test with some pretty poor results a couple weeks ago but I'm not sure if it was due to the crappy tester or not and haven't had time to purchase one.
 
Barnacle_Bill

Barnacle_Bill

Admiral
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Feb 8, 2004
Messages
6,469
Re: Mercury 850 problems

Did you use new gaskets, needle and seat when you rebuilt the carbs? Set the float level's? There should not be gas coming out when pumping the primer bulb.
 
M

MillerSVT

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Joined
Mar 13, 2010
Messages
26
Re: Mercury 850 problems

bhile said:
Did you use new gaskets, needle and seat when you rebuilt the carbs? Set the float level's? There should not be gas coming out when pumping the primer bulb.
Click to expand...

all new gaskets, needles and what not. Was a parts from mercury. The replacement floats were all plastic (the arms and everything) so how would you go about setting the level?
 
M

MillerSVT

Cadet
Joined
Mar 13, 2010
Messages
26
Re: Mercury 850 problems

obviously i did not set the floats... FAIL. Where do you measure from when setting the floats. Looks like it's coming apart tomorrow....
 
M

MillerSVT

Cadet
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Mar 13, 2010
Messages
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Re: Mercury 850 problems

Anyone out there able to tell me how to measure the float level?
 
C

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,142
Re: Mercury 850 problems

Side bowl carbs, right?

Sure invert the carb covers. The levers should be straight across, parallel with the carb cover. Turn the carb cover right side up, There should be 1/4" between the carb levers.
 
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