Author Topic: Overnight leaking..what else besides well plugs  (Read 4570 times)

Offline Fairlane514

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Overnight leaking..what else besides well plugs
« on: September 08, 2009, 10:48:20 AM »
I have a 70 Corvette 454 original 7040205EH carb, motor is stock with the exception of a Comp Cam 286 extreme energy( 224/230, 520 lift, 110 lobe).
I rebuilt the carb with Cliffs kit..........I drilled,tapped and epoxyed the well plugs, but I still get a leak down overnight. I pulled the carb this morning and there was a puddle of fuel in the intake. I lifted the carb straight up and I could see the primary well plugs looked wet, the secondaries looked dry. When I took the choke plate off the bowl was about half empty.  Is there somewhere else it could be leaking? Needle seat? (its new with Cliffs kit) I did not see any puddles on top of the primary plates.
I really dont think the well plugs are the culprit since I drilled, tapped epoxyed them.
I also feel like this is the cause of my tuning issues.

Any thoughts on APT starting point?

Thanks 

Offline Cliff Ruggles

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Re: Overnight leaking..what else besides well plugs
« Reply #1 on: September 09, 2009, 03:42:22 AM »
After installing the screw in bottom plugs, did you invert the casting, apply dish soap water to it, and pressure test it with compressed air?  Any leaks will show up as a stream of bubbles. 

I've never had screw in plugs leak to date if we used Marine Tex on the threads when installing them.....Cliff

Offline Fairlane514

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Re: Overnight leaking..what else besides well plugs
« Reply #2 on: September 09, 2009, 02:31:49 PM »
No I did not check with pressure.

I took the carb apart and put fuel in the bowl with choke plate on and let it sit overnight. I noticed the level was dow n, but no evidence of an obvious leak. The well plugs looked and felt dry.

Do you think it could be a crack in the bowl that only leaks when its hot and then closes when it cools? This may explain why the bowl only empties about halfway overnight.

Offline Cliff Ruggles

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Re: Overnight leaking..what else besides well plugs
« Reply #3 on: September 15, 2009, 04:06:20 AM »
A pressure test with dish soap and compressed air will find any leak in the bottom of the casting....Cliff

Offline Fairlane514

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Re: Overnight leaking..what else besides well plugs
« Reply #4 on: September 15, 2009, 01:06:31 PM »
Did the test an no bubbles. I repositioned the needle by turning the wire hangar to the front near the power piston and thought things got better, but when I drove the car the car today it idle sometimes and other times it slowly dies until I hit the gas to keep it running.

I thinking I might start looking for a box to put it in and ship to you.

Offline cobalt327

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Re: Overnight leaking..what else besides well plugs
« Reply #5 on: October 30, 2009, 10:43:54 AM »
Is it possible for the accelerator pump circuit to allow fuel to siphon over, if the check ball isn't properly seated by reforming the seat w/a good, used check ball- as outlined in "The Book"?