BadBaran

I have a Holly 650 carburetor that is about 3 years old and just started pumping gas out of the front vent tube. I tried to start the car and it would crank but not start. So I opened the hood and there was gas sitting all over the intake manifold. I started to crank the car again and gas started pumping out of the vent tube again.

The car ran fine 4 days earlier.

Do I need to rebuild the carburetor or does this sound like something else?
Thanks

1986coupe

Gas coming out of the top sounds like some sort of obstruction, large or small. Since gas is involved it is in your best interest to take the carb off the car and have a look.

scottyp99

Sticky float won't close the float valve? Take it apart, clean it up, put it back together with new gaskets. The only times I've ever seen gas shooting out of the vent, it had something to do with the float not working properly. As far as it running fine 4 days ago, well, sometimes things gradually wear out, and sometimes they work just fine, right up until they don't work at all. Nature of the beast, brother!


Keep the shiny side up!
Scott

Korevette

As above, and please take it apart to fix.

I am guilty of hitting the float bowl with a Crescent wrench to free up the needle in the seat. That may have cut it in the old days BUT, fuel around a engine and a plastic car are nothing but bad news.

Have a good look at your fuel filter, it maybe past due.

scottw

I almost ran out of gas a few months ago and sucked up the crap at the bottom of the tank. Clogged it up and had the same thing happen. Bought a rebuild kit and fixed it. You can also try just the needle/seat but I just paid a few extra dollars and did the kit.

gotz06?

Like others said float is stuck more than likely due to trash rebuild it or have it rebuilt. Holley carbs are not that hard to rebuild! Main thing is to get it clean. If you don't have one already install an in line fuel filter while your at it

BadBaran

Thanks for everyone's input. Looks like I'll be buying a rebuild kit and going from there. Thanks again

bill69

So you definitely have a problem with the float not stopping the gas, for that you will need a rebuild kit or at least a new float, needle and seat as the others stated. Also just for safety sake I would recommend removing all the spark plugs and move the wires out of the way as to not ignite the gas, and turn over the motor and pump out any gas that you may have in your cylinders. You could do some damage to the motor if you have gas in the cylinders and you try to start it as raw fuel doesn't compress very well.

scottyp99

Good point! And if raw fuel has been sitting in the cylinders for any length of time, some has probably leaked past the rings and into the crankcase, probably be a good idea to change the oil, too.


Keep the shiny side up!
Scott

69 Chevy

Spelled HOLLEY. 650? Do we need to guess what model? Perhaps it's a 4150 like mine?

No need to take the whole carb apart if there's a spec of dirt holding open the primary needle/seat letting fuel flow out of control.



With a wide blade screwdriver, remove the screw, gasket and adjusting nut for the needle and seat at the top front of the fuel bowl. Remove the needle and seat...check the tip of the needle and the inside of the seat for debris. Check the O ring for condition. When satisfied everything is OK, re-install to about the same height as when you began. Remove the coil wire to keep the engine from starting. Crank over the engine to make sure the needle/seat is sealing properly and fuel no longer spews from the bowl vent.

Then remove the sight plug. Fuel should be no higher than the bottom threads of the sight hole. If not at the correct height, start the engine and adjust the 5/8" nut of the needle/seat. Then tighten down the top, wide bladed screw. Done deal.

capevettes

I agree with 69 Chevy. Start there. I have had the needle valve cause this many times over the years. Pull it, blow it out and re-set your float bowl levels. It takes about 3 minutes and that has fixed it many, many times for me. If not, you may need plan B as others have stated. Good luck

PeteZO6

I would only add that besides checking the needle/seat for junk, blow it out with clean compressed air. I failed to blow mine out, just checked it, and put it back. Same problem, so I had to remove the needle/seat and blow it clean. Then it was fine.