1964-65 Mercury 3.9 problem

[Slyomax]

The motor will start on the first pull at full throtle but as soon as I move the handle to low idle it stalls.. I turn the handle just to say, half inche, and it wont run. I cleaned the carb, cleaned the cap and magnets, new spark plug and nothing works. There is sparks at low or fast idle.. Don't know what to do nomore..

[AMD Rules]

Did you check the points for condition & gap?

Do you get a -strong- spark across a 3/8" gap to ground if you insert a bolt into the spark boot and pull it over?

How did you set the low idle jet?

Try running that motor at night and look for arching wires as you move the throttle from fast towards idle. Pay particular attention to the wires up under the flywheel that move with the throttle arm.

Checked compression?

Weak fuel pump?

Float setting in the carb?

Any fuel leaks noted?

Does it run at idle if you pump the primer bulb by hand?