Carbs popping , Vac adv. fluctuating

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Danthesignman
Posts: 66
Joined: Wed Jan 20, 2010 5:53 pm

Carbs popping , Vac adv. fluctuating

Post by Danthesignman »

As it read , the carbs are backfiring like they are lean . These are 140 carbs I got from M. Nall that where supposedly modded by Unsafe . I was warned that they might be a little rich , but they act like the opposite . Secondaries are not hooked up . I ent to the car wash and noticed that the vac. adv. is fluctuating with the rpm of the motor . The motor runs good and does not miss except for the popping back , it`s usually under acceleration , it cruises at a constant speed smoothly .
Is it a burnt valvle ? It seems to do it on both sides , maybe the valves are too tight . I have to run this afternoon but I`m going to run a comp. test tonight .
Thanks , Dan :ty:
Danthesignman
Posts: 66
Joined: Wed Jan 20, 2010 5:53 pm

Re: Carbs popping , Vac adv. fluctuating

Post by Danthesignman »

forgot the notify me checkbox... :rolling:
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terribleted
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Joined: Sun Apr 18, 2010 2:36 pm
Location: Atlanta, GA
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Re: Carbs popping , Vac adv. fluctuating

Post by terribleted »

Just a thought. Are you sure the secondary are fully closed (would make things lean). Timing/ignition can cause popping back as well.
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
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Located in Snellville, Georgia
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