Thompson Performance PBP H-1 Atomizers

[WaltZ]

Any thoughts on these atomizers?
Anyone using them?
for my 1969 holley 780 4053 with a minor hesitation from stop
Thanks in advance

[crossboss]

Sounds like you have an off idle lean stumble. Adjust the carb, and possibly change out your squirter to a 1-2 size larger one. That should cure the issue.

[WaltZ]

was much worse earlier, went larger from 25 to 28 squirter and almost completely gone. could a 30 be too large for this, or should I try it and see

thanks

[crossboss]

was much worse earlier, went larger from 25 to 28 squirter and almost completely gone. could a 30 be too large for this, or should I try it and see

thanks

Sounds like a bigger issue. Check your manifold vacuum, might be a leak.

[WaltZ]

checked and all good on that end.. just ordered a .031 to try that.
will update in a few weeks when I get back to this issue.

[crossboss]

Have you tried to adjust the accel pump?

[WaltZ]

yes and no changes and now reset back to spec.
like I say it's a very minimal. maybe I am just too picky.

[plumL78]

try adjusting the air bleeds richer that usally helps

[z28z11]

4053 stumble off idle is a common problem, I found this out in 1973 right after the X77 came home. Increasing  the squirter size usually helps, you can also change the pump cam and/or go to a 50cc accelerator pump. Tailoring the rate and volume of the accelerator pump shot is the best cure, make sure your distributor is in good shape and timing is in spec for initial and total advance.

Regards,
Steve