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Fuel too lean

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dawgs

Regular Contributor
how do i adjust the fuel mixtu

how do i adjust the fuel mixture on a mercarb? where is the adjustment screw?
 
if its a mercarb 2bbl it will

if its a mercarb 2bbl it will be on the throttle body at the bottom of the carb turn the screw in till it just bottoms out back it off 2 turns to start . start the engine and slowly turn it one waty untill you her a rpm drop then the other way untill you here achange then center it between the 2
 
"that's idle mixture only

"that's idle mixture only if I'm not mistaken.

First question that comes to mind is "what are you trying to solve for?". Frequenly when people fool around with idle speed and mixture, they are not solving the real issue. Just thoughts.

If you think you have a mixture issue at idle, look for vacuum leaks along the intake (carb gaskets, vac lines, port gaskets, etc)"
 
ok i messed with the timing a

ok i messed with the timing a little and adjusted the mixture screw...now i hit the throttle...no stalling...perfect right? well after about an hour of driving...i put in neutral and the try to accel and the same thing happens...any ideas?
 
"When you set the timing to 8

"When you set the timing to 8 deg. BTDC, did you check it AFTER you tightened the hold down bracket? Tightening the bolt can throw the timing off.

I set the timing off by about 1/4 degree and let the bolt tightening make the 1/4 deg. change to 8 deg. BTDC. To help you keep the dist. on the 8 deg. mark, set it and scribe it for reference. You can also use a peice of tape with a dark straight line drawn on it and place it on the shaft and manifold. Now take a razor knife and cut it across the line. The two pieces are your alignment marks to hold when tightening the bolt.

With the engine at operating temp. when you adjusted the carb., did you start (engine off) by turning the screw inward until it just touches the seat and then back it out 1.5 - to 2.0 turns to start? Now with the engine idling at the proper RPM, SLOWLY move the mixture screw out until the engine started to stumble, make a mental note of the position, then SLOWLY move the screw in the opposite direction until it stumbles, make a mental note of it, then back the screw to the position that is between the two points? A Merc. carb single screw is not easy to detect the exact moment it starts to stumble so it takes some focus. If you have a vacuum gauge and can find a port on the manifold, it will help detect when the RPM stumbles by the needle fluctuation.

Guy"
 
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