carb/fuel help!

[impinhigh]

hey all,
it's been a weekend of set backs since my 1600 was brought back to life. Here's the problem:

Car starts and idles as normal, then take the rpm's up and get the fuel pump going, drop back down to idle, within 30 seconds it running on 2 cylinders and fuel starts to pour out of the over flow from carb 2 (nearest to fire wall). No fuel from #1 over flow.

I pulled the tops off the fuel bowls and the appear normal. Floats seem to be intact. I did lift the pistons at idle and the car ran with the front one up but would die with the rear one up.

The car has been sitting for a while but the gas looks ok. Could it be a problem in the return line to the tank?

TIA for any help you can pass along.
Matt

[SLOroadster]

Is your rear float needle valve sticking open? When it dies, check the plugs on the rear carb. If they are wet, it is flooding. Also pull the dashpots off and make sure everything is clean, and any vents are clear. I hope that will help,
Will

[S Allen]

My vote is for a sunk float or a sticky needle valve or both. The grosse jets on my newly rebuilt 2 liter carbs would pump fuel out the over flow tubes because the little vlave in the jets would not seat letting fuel overflow the float bowl. I also had a sunk float. It had gas in it so it never touched the needle valve. Same synptom fuel flowing out the overflow. Good luck.

Steve

[impinhigh]

The collective opinion is the rear needle valve, it looked ok at last view. Going back in for more surgery afterwork. I'm still concern about the fuel return line.

Matt

[steve68]

my back carb will flow fuel out of it after having it off the car everyu time..just tap the bowl with a screw driver always worked for me..doens't do it agian (until i take the carb off again)

steve

[Datrock]

Matt, while you are tinkering around with the carbs it might be worth removing the gas feed to the bowls to see if you have the small round screens in the fuel input lines to both carbs. If the screens are missing you could be getting small particles stuck in the float needle. Also check and see if the needle has a groove in it, if so it may need to be replaced so you will have proper seating to stop the flow of fuel. You will need to remove the needle from the bowl to inspect it. This is a problem that alot of us have encountered at one time or another. Bill

[impinhigh]

I did check the banjo fittings on the front carb last night and found no screen. I ran out of light before I got the second one off. Will check rear banjo and float valve tonight.

Matt

[impinhigh]

I inspected the float valve last night and there is every indication that it is functioning correctly at least when off the car. It's clean with no grooves, I also did a blow test, needle up no air, needle down and I get air. I inserted the over flow into water bottle to collect the gas and it filled within 30 seconds of starting the car.

Have extra carb and will install Thursday..

ideas?

[S Allen]

Matt,

It does not take much to get the needle to get stuck in an open position. If you have any crap floating around in your gas tank or some where else down the line that can happen when ever. If you have a spare carb-pull the needle valve out of it and replace the one already in the carb or just swap float tops. If the float is not sunk the needle valve has to be the culprit. That is what stops the flow of fuel once the float closes the valve. It is kind of scary when you see fuel pumping out the overflow close to the hot exahust manifold. Been there done that! Rapping on the carb float bowl with a screw driver can sometimes bust the debris loose but that does not fix the root of the problem. Have you had your gas tank cleaned and sealed?

Steve

[impinhigh]

tank and line cleaning are on the list... But I tell you that float valve was really really clean and so was the bowl and the gas coming out of the float bowl. What if its the return line to the tank. I blew into it and heard bubbling in the tank but I had to blow hard!! Ok no funny remarks). I did try to remove the float valve but it was in tight and I didn't want to mar the brass. Thursday I'll try swap'n the carp and I'll report back.

Matt

[Datrock]

Matt, I agree with Steve on the problem of being the rear float needle not seating.. Sounds like your float floats and the needle looks good!
Have you tried bending the brass part that the float raises against to shut off the fuel. The arm on it maybe to high to where the float is not touching it to shut off the fuel. Doing this fix will lower the fuel level a little but may solve the overflow. Bill

[impinhigh]

YES!!!!!!!!!!! I swap'd a float valve top and the problem has been resolved.

Thanks to all for the input!
Matt

[S Allen]

Matt,

Glad to hear you got it handled. Persistance does pay off.

Steve