Author Topic: Vacuum leak at idle, hard start  (Read 3505 times)

Offline W30Olds

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Vacuum leak at idle, hard start
« on: May 26, 2014, 06:34:15 PM »
Would incorrectly indexed secondary plates cause a vacuum leak at idle? make the engine hard to start? I rebuilt the carb and used bronze bushings but I believe I might not have indexed the secondary plates correctly, everything else looked fine.

Offline ejowrench

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Re: Vacuum leak at idle, hard start
« Reply #1 on: May 27, 2014, 03:54:02 PM »
Perhaps. Place a wet rag around the secondary air valve, sealing it. If the idle does not change, look some where else....

What makes you think you have a vacuum leak?

Offline W30Olds

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Re: Vacuum leak at idle, hard start
« Reply #2 on: May 27, 2014, 04:22:19 PM »
Its off the car now, apart. I placed a rag over the primaries when it was running and didnt do anything, then placed a rag over it with both hands sealing it and just barely changed the idle.  The engine made 18 inches of vacuum at idle warmed up, but started kind off hard. The engine was shaking and you could hear it through the exhaust, sounded like a miss or vacuum leak.

I put a reman qjet on it and it definitely idles better than the rebuilt original.

Offline Cliff Ruggles

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Re: Vacuum leak at idle, hard start
« Reply #3 on: May 28, 2014, 02:12:47 AM »
What method did you use to install the bushings?......Cliff

Offline W30Olds

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Re: Vacuum leak at idle, hard start
« Reply #4 on: May 28, 2014, 04:18:56 PM »
Your kit, per instructions.  Should the secondary plates show any light through them closed?

Offline Cliff Ruggles

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Re: Vacuum leak at idle, hard start
« Reply #5 on: June 02, 2014, 03:57:51 AM »
Very, very little light when they are fully seated/closed and correctly adjusted....Cliff

Offline W30Olds

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Re: Vacuum leak at idle, hard start
« Reply #6 on: June 06, 2014, 09:42:46 AM »
Ok, what about these defects in the main body? The first one is a hole through the first wall of the casting, right after the baffle, the other side of the secondary isnt touched. You think any of these are causing a leak?


Offline Cliff Ruggles

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Re: Vacuum leak at idle, hard start
« Reply #7 on: June 12, 2014, 09:53:08 AM »
Can't really tell by the pics as they are out of focus slightly.  The top pic wouldn't produce a vacuum leak, not sure about the bottom pic?....Cliff