Pop-off like a wet fart?!

[Quinc]

All of a sudden the Blaster is no longer idling and it needs throttle and a prime to start (runs great after that no dead spots) So figured I would start with the carb...

Checking the pop-off and right before it "pops" it slowly leaks out air around the needle and then it might give a little pop...

So far I have tried:
-blowing the carb out with carb cleaner
-Putting in a new needle and seat
-increasing pop off from 12 to 24
*Note carb was rebuilt last season and has less then 30 hours on it.

Any ideas? Or is this normal? My other carb holds air and then gives off a POP and sprays gas all over the place with zero air leakage.

 

[SVTPete83]

Bad gasket somewhere?

 

[High Speed Industries]

Did you replace the needle and seat with a new one? Is the O ring on the seat in good condition? Have you checked the pulse side of the carb?

 

[Vumad]

Did you use mikuni parts?

 

[Quinc]

I think I figured it out. Needs gas/wd40 in there to complete the seal. As long as I refill it with wd40 after each "release" it is good to go. Now onto how is going from 12psi to 21psi with the same jetting going to change things...

 

[Vumad]

I think I figured it out. Needs gas/wd40 in there to complete the seal. As long as I refill it with wd40 after each "release" it is good to go. Now onto how is going from 12psi to 21psi with the same jetting going to change things...

It's going to push the transition to a higher RPM range, making the low-mid range leaner.

And yes, you must wet the needle before testing. Also, hold the needle open and pump out all the remaining fuel, then wet with WD40, before testing.