If the timing is set right and the carbs are balanced, then the vacuum leak is most likely the cause of the rough idle. However, knowing of the vacuum leak, you can not accurately balance the carbs if you have a vacuum leak in the left or right bank. Correct any leaks and repeat the balance procedure, and you will have a happy purring engine. Corvair forums are a great resource for the diagnosis of problems. Invest in a timing light to fine tune the timing. I tend to use both a dwell meter and a timing light as I can find a happy medium for the best reliability.

A couple of things....first, your car looks like it's a stick shift. Powerglide cars are according to the Chevy shop manual, adjusted in Drive, but then you can have a fast idle in Neutral. Second, you can use a 1/4" socket drive wrench with extension to more easily adjust the fast idle screws, I think it's a 1/4" socket. Then there's no chance of the screwdriver slipping off the screw.

Hello and thank you for this video. I learned the reason for the standard type screw heads on the adjustment screws is so it is easier to see how many turns you are doing on the adjustment screws. I learned this from the D3SShooter You Tube channel on adjusting the Weber carb that I put on my turbocharged Corvair. I just a bought a Corvair with a 140 engine and now need to learn how to sync the carbs. So again thank you for posting this video.

Hey bud I like your Corvair videos but why are you filming with a Panasonic VHS camera?

Dogs CAN look up!

Very cool to see, I’ll have to adjust my ‘64. Think I may have a vacuum leak as well engine wants to quit after a few seconds as of recent

Thank you so much this video was exactly what I was looking for

I’m enjoying your banter.

I’ve been struggling to get my 4 carb setup working well so much so that just to get the car on the road (been off the road since 1994), I’m thinking of making blocking plates and going to two carbs for a while. Did you use a two carb setup or just omit the secondary linkage? Any advice?

This was made in 2023? Info is totally inadequate. The synch tool doesn't dictate the system. It is adjustable and a tool. You wouldn't tell someone to adjust a wrench to half way and work on their motor.