Author Topic: Carb internal vacuum leak  (Read 3428 times)

Offline swilliams

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Carb internal vacuum leak
« on: December 27, 2014, 10:25:38 pm »
1986 Chevy C10 350. I seem to have an internal carb vacuum leak. It is on a Edelbrock 1600. It is a noticeable sucking noise. I have sprayed carb cleaner around the base of the carb and find no change in idle speed but when i spray into the primary and secondaries  the idle raises. I have changed the upper gasket when i did a jet and accelerator pump swap. What do i need to check or should i have it rebuilt. I was thinking about trying one of the Summit 600cfm carbs. Any ideas and comments welcome.
« Last Edit: December 27, 2014, 10:27:12 pm by swilliams »

Offline Irish_Alley

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Re: Carb internal vacuum leak
« Reply #1 on: December 27, 2014, 11:14:30 pm »
could be an intake leak.
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

Offline swilliams

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Re: Carb internal vacuum leak
« Reply #2 on: December 27, 2014, 11:19:11 pm »
would i here it through the carb? I have not checked that and i did do a head swap in the past few months. I will check that out.

Offline Irish_Alley

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Re: Carb internal vacuum leak
« Reply #3 on: December 27, 2014, 11:25:14 pm »
tell you the truth my holley on my 79 mud truck always seamed like it was sucking air. changed the intake and carb gaskets still no change. rebuilt the carb and still sound like it. but if the intake was leaking the sound could be sounding like it is coming from the carb
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

Offline swilliams

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Re: Carb internal vacuum leak
« Reply #4 on: December 27, 2014, 11:31:02 pm »
I just thought with the cleaner in the carb and a raise in idle it would be a leak of some sorts. I will check the intake tomorrow.

Offline Irish_Alley

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Re: Carb internal vacuum leak
« Reply #5 on: December 27, 2014, 11:40:21 pm »
no thats natural the cleaner doesnt burn like the fuel or air thats in it now. you mixed your air to fuel ratio. signs of a leak will be a raised idle rpms
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

Offline swilliams

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Re: Carb internal vacuum leak
« Reply #6 on: December 27, 2014, 11:48:18 pm »
Ok so it may just be  the way it is. I will check the intake bolts to be sure. Thanks