Dragster only idles on choke.

[Bufficus]

My rarely used Dragster has developed a problem where it will only idle with the choke on even when warm. Once off the idle circuit it runs fine.

It has a flip choke conversion on a standard PHVB 20.5 carb, which until now has been faultless.

I assumed it was a blocked pilot jet, but have stripped and cleaned the carb twice, but the problem persists. The reeds appear to be fine.

Am I missing something obvious?

[Rich_T]

Could be an air leak, old fuel?

[Bufficus]

Thanks for the input Rich.

It has new fuel and no obvious signs of an air leak.

I had another little play today and it seems it won't run at all without the choke.
It hasn't got hot enough for me to suspect it may be electrical, besides I have tried a different CDI and it's the same.

I was wondering if it could be some kind of fuel starvation issue. Although it seems to flow ok if the pipe is removed from the carb.

Does anybody know how the automatic fuel tap works on a dragster or how to remove it?

[ferritt]

works on vacuum i believe, think psn it batley do a manual replacement tap

[Bufficus]

Thanks I'll give them a call.