40 MERC CARB PROBLEM

[SHAWNC24]

" MY 40HP MERCURY WILL IDLE GO

" MY 40HP MERCURY WILL IDLE GOOD FOR A FEW MINUTES AND THEN STALL. I CAN EVENTUALLY GET IT FIRED AGAIN. ALSO, WHEN YOU TRY TO GIVE IT ANY THROTTLE PAST ABOUT QUARTER THROTTLE SHE JUST BOOGS DOWN. I REMOVED BOTH CARBS AND CLEANED THEM. THE LOWER CARB HAD SOME JUNK IN THE MAIN JET. THIS DID NOT HELP. IT STILL DOES THE SAME THING. ANY IDEAS??? "

 

[joereeves]

"Shawn.... Mercs are not my li

"Shawn.... Mercs are not my line of expertise but your problem is a common one, and since there has been no answer her, I'll try to help.

Assuming that you have good compression and spark on all cylinders (you did check those areas, didn't you?), your hesitation problem could be caused by the following:

1 - The carburetor(s) are still not clean enough, and something is clogging/fouling the jets, restricting the fuel flow.

2 - Whatever advances the timing on a Mercury is sticking, causing the timing to stay somewhat retarded.

3 - The carburetors are opening too soon in relation to the timing.

There may be something else on a Merc that would cause this that I'm not aware of. Hopefully Tony, Jon, or someone will jump in here with another answer.

Joe

"

 

[SHAWNC24]

" JOE

THANKS FOR THE INFO.

" JOE

THANKS FOR THE INFO. I DID GO BACK THREW THE CARBS AND FOUND MORE JUNK. I THINK A GAS LINE WAS FALLING APART AND ITS GETTING IN THE CARBS. I HAVE NOT YET BEEN ABLE TO GET OUT AND TEST IT TO SEE IF I FIXED IT, BUT I WILL LET YOU KNOW WHAT I FIND. I DID NOTICE ONE THING, THE LINKAGE THAT CONNECTS THE CARB THROTTLES TO THE SHIFTING LINKAGE WAS BENT. COULD THIS CAUSE WHAT YOU SAID ABOUT THE THROTTLE OPENING TO SOON IF I DONT HAVE IT BENT BACK CORRECTLY? IS THIS A CRITICAL ADJUSTMENT THAT NEEDS TO BE PRETTY PRECISE? THANKS AGAIN FOR ALL YOUR HELP. I APPRECIATE IT. "