Howdy,

I cannot quite grasp the problem. I have not encountered this before. As pointed out, excessive pressure should manifest as fuel leaking from the vents in the bowls. Are your vents clear?

If you want, you can bypass the pump. Gravity feed the carbs. Hang a temporary tank from the latch on the hood, er, bonnet and see if you can gain a more normal adjustment for idle.

You mentioned the needles were installed flush with the piston face. Where are your jets? How far do the jets move down with the choke lever?

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Mr. Shannon DeWolfe -- I've taken to using mister because my name misleads folks on the WWW. I am a 53 year old fat man. ;-)