carb drain back issue
#1
carb drain back issue
Last summer, had to tear into a great reman quadrajet. The linkage that connects to the shaft out of the hot air choke and goes up to connect to the butterfly had slipped off somehow off the shaft of the choke...
Clearance was just enough that through operation/vibration it slipped off. We machined up a washer to take up the clearance and re assembled. But since then after running the car and it sits for a day, the fuel seems to drain back. As it takes a lot of cranking to get it running.
I did not replace that top gasket when we re assembled the carb, and have re tightened the 7-8 screws that hold the top down. Haven't had a chance to see if that fixed the problem. But noticed around the accelerator pump side that the gasket sticking out was wet and visible where gas had leaked down around that area.
Guessing that gasket is use once piece? Not thrilled about tearing back into it to replace...
Clearance was just enough that through operation/vibration it slipped off. We machined up a washer to take up the clearance and re assembled. But since then after running the car and it sits for a day, the fuel seems to drain back. As it takes a lot of cranking to get it running.
I did not replace that top gasket when we re assembled the carb, and have re tightened the 7-8 screws that hold the top down. Haven't had a chance to see if that fixed the problem. But noticed around the accelerator pump side that the gasket sticking out was wet and visible where gas had leaked down around that area.
Guessing that gasket is use once piece? Not thrilled about tearing back into it to replace...
#3
Rather than guess if the fuel is 'draining out' take off the carb top before cranking to verify. A wet top gasket would indicate over-filling or too high a float so I don't understand the logic there. Some on these forums will tell you it's impossible for the fuel to escape past the well plugs and drain the bowl. I won't get into that argument but I do know it's impossible to drain the bowl through a siphoning effect back out the feed connection. It's just physically impossible given the parameters of the bowl and the mechanics involved.
#4
Is it better to always replace the gasket...yes. Can it be reused without problems...if it was in good condition...yes.
I'd check to see if the choke is closing completely when the engine is cold before opening the carb. It could be a choke problem again.
Good luck!!!
I'd check to see if the choke is closing completely when the engine is cold before opening the carb. It could be a choke problem again.
Good luck!!!
#5
Remove the coil wire. Look down into the carb with engine off, operate the throttle and see if there are 2 streams of fuel spraying. If so the float is probably too high and flooding as stated above.
#7
Is it better to always replace the gasket...yes. Can it be reused without problems...if it was in good condition...yes.
I'd check to see if the choke is closing completely when the engine is cold before opening the carb. It could be a choke problem again.
Good luck!!!
I'd check to see if the choke is closing completely when the engine is cold before opening the carb. It could be a choke problem again.
Good luck!!!
In the final gasp here with hopefully the last snow storm here in NW Iowa.
Went out to the garage and removed air cleaner, thumbed throttle and again choke didn't fully close. Couldn't get it to finger close, as something may have been caught up, or just where the spring was set. Tinkered with the dial, re thumbed the throttle and butterfly snapped closed. Fired up the car with way less cranking, let it run for a bit to visibly verify that the choke would start coming off, and it did. woo hoo
WIll go out later when it cools and thumb it again and see if it closes fully again.
#8
Sometimes there is wear in the lever behind the choke housing that the choke link connects to. We have had several that needed to be replaced. Just letting you know if you have a reoccurring issue. I rebuild Quadrajets for a living, there are a few issues that need to be addressed with a rebuild, or even just removing the air horn. You mentioned that your carb. is a remanned unit?
#9
Keep in mind that you have to hold the throttle open while trying to close the choke plate with your finger. If the throttle is at the slow idle position, the fast idle cam will not let you close the choke plate all the way unless the throttle is held open.
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rootney
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November 20th, 2014 12:39 AM