I have a 51 pontiac with its original straight eight engine and carb. I have a issue I never came across before. After warmed up, she idles high. If I take the air cleaner off, the idle comes down. It will then go back up if I put the cleaner back on. Thanks for any suggestions. Sent from my SM-G935V using The H.A.M.B. mobile app
Yes. I tried a aftermarket one as well and it does the same thing Sent from my SM-G935V using The H.A.M.B. mobile app
viscosity is not even a consideration if you know how the oil bath works.I think minor vacuum leak crack in line or plugs used to plug excess vacuum ports.I say minor if big you would notice higher rpm even with breather on.also I think you would hear hissing sound from leak.pretty hard to have a restrictive oil bath unless oil over filled even then it would just choke engine for air and lots of black smoke.with a tac you could check rpm gain I suspect if no leaks then the sound of air rushing into carb makes you think it is speeding up a tac would show
I was going to ask how viscosity would affect it. I did a fast check for vacuum leaks with carb cleaner but did not find any. I know for sure even without the tach that the idle is going up when the air cleaner is put on cause the rise in idle is to big. Sent from my SM-G935V using The H.A.M.B. mobile app
I recall a Pontiac (O.T., later model) that our boss, Cliff, sent over to "Big Bill" to be smogged...(Calif. thing) Big Bill called back and said it had leaky vacuum hoses...Cliff told him to just go ahead and replace 'em. The car got delivered to us around 2:00 P.M., but was smoking to beat the band! Real smokescreen... Cliff put it on the big 2 post hoist, (for doing ****** changes) and I looked it over... Big Bill had the vacuum line for the transmission modulator connected to the automatic transmission breather tube! Our American Indian mechanic joked: "Mmmm! Big Bill make-um heap big smoke!"
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