Roads.zx

1965 289 v8 stock w/ Petronix timing;

I rebuilt the carburetor using kit, everything was dipped, everything seems fine ; but, while adjusting the idle mixture screws I noticed the right screw doesn't seem to have any effect.
The left screw will kill the engine if too lean and is responsive if too rich. While I see no visible damage to the right screw I'm thinking I should buy a new mixture screw. ( they didn't come with kit, nor the main jets either)

Your thoughts are appreciated.

Thanks

jojobanks

try taking the unresponsive screw all the way out and blow it out with compressed air (can of keyboard cleaning stuff will work). The passages in there are pretty small and even dipping can still leave crud in there. If you haven't blown all the passageways out with compressed air then I would do so.

If you've already done this, then I would either buy a new idle mixture screw or try to check the seat for damage.

kalli

either the screw is not seating properly or there is dirt still in the passageways

Coupe

Do you have any slop or play in the throttle shaft on that side? If so you could have a vacuum leak?

Roads.zx

Throttle shaft appears tight, blew out the mixture passageway and got good air coming out the float bowl and the venturi.

I'm going to replace the mixture screw/needle; but, I think the seat of the mixture screw must be damaged so I'm planning to buy a carburetor bottom shell and start over if the new mixture screw doesn't do the job.

Thanks for the feedback.