Author Topic: 305 FAST IDLE  (Read 3282 times)

Offline 1986GMCSierra

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305 FAST IDLE
« on: December 28, 2014, 10:58:22 AM »
i have a 1986 stock 305 and 700r4 tranny.. what carburetor  would be best to stop a high idle and get a little more power out of the motor?

Offline Irish_Alley

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Re: 305 FAST IDLE
« Reply #1 on: December 28, 2014, 12:17:15 PM »
High idle is a sign of a vacuum leak
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Offline 1986GMCSierra

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Re: 305 FAST IDLE
« Reply #2 on: December 28, 2014, 01:23:22 PM »
i guess it could be coming from my intake manifold both where it mounts to block and where carb mounts to it..

Offline 1986GMCSierra

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Re: 305 FAST IDLE
« Reply #3 on: December 28, 2014, 01:24:29 PM »
High idle is a sign of a vacuum leak
what is the easiest way to check for a leak?

Offline Irish_Alley

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Re: 305 FAST IDLE
« Reply #4 on: December 28, 2014, 01:33:37 PM »
No easy way. Could be a vacuum hose leak, could be the carb or carb or intake gasket. Try and listen for a sucking sound. If you have some sort of starting fluid you can spray that around the carb and intake or something flammable like a propane torch not lit but turned on a engine vacuum leak could suck it up and will raise the idle
« Last Edit: December 28, 2014, 01:38:36 PM by Irish_Alley »
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes