Losing prime

[cwb]

Question: Why would my 2F Aisin carb lose prime? It runs fine but has to have gas poured in the carb, even after it gets warm.

Help!

 

[Steel]

It may be that your gas tank is not properly venting (clogged line vent line), which would cause there to be a vacuum. Also if you live in a hot climate and your carb fan isn't working, the fuel left in the carb might evaporate out when you shut off the engine...

 

[cwb]

I don't think it's the carb fan because I can shut it off and immediately try to start it again and it won't. It runs great after it starts. Other thoughts?

 

[theo]

Leaky needle and seat letting the bowl drain? But that should also cause it to run rich and you say it runs fine. (??)

 

[65swb45]

Any other symptoms. I'm thinking possible hesitation when you let out the clutch on upshifts?

Mark

 

[cwb]

It wasn't doing it before, but, yes, I've noticed it stumbling sometimes now--usually in 3rd or 4th gear. It will stumble/hesitate briefly, then go on and run okay. It will start three or four times in a row and then all of a sudden, nothing. Then I pour a few drops of gas in the carb, and Zoom. Frustrating.

 

[65swb45]

When you have hard starting AND stumbling, that's usually sign to look into the accelerator pump.