Murray said

This doesn't seem to be fuel related since you have tried two carbs. Need a better desription of the problem. What does "no response" mean? Does it hesitate? Are you running a vacuum advance? Where is the timing? Motor? At all speeds? Is there a "miss"? Help![

Tooljunkie said

Fuel pump.
Damaged/collapsed fuel line.pickup screen clogged.
Dirty fuel filter.

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When driving and you push the accelerator nothing happen and you have to reapply it and sometimes it picks up and sometimes back fires it mainly happens at higher speeds.

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