Fuel Overflowing Float Bowl

[LickskilletM37]

I just got my 52 M37's ignition working and the motor starts good but runs very poorly, especially as I apply throttle. I've discovered that the float bowl needle valve is not completely shutting off and fuel is overflowing through the vent into the intake. I have recently rebuilt the carb with a kit from Daytona Parts, so the needle valve assembly is new. It also has a Facet 60104 electric fuel pump with no regulator, but the max pressure for that pump should be 4 psi.

Should I try installing a regulator?

Thanks,

Chuck

[ZGjethro]

When I bought my 52 truck a few years ago, it had a 12v pump center tapped off the batteries and it was causing electrical problems. It also had a faulty pressure regulator right at the carb and my float was over powered by the pump, leading to constant flooding. I replaced it with a low pressure 24v Facet pump and inline filter back by the tank and installed a Holley pressure regulator in the engine bay where the factory fuel filter had been installed. My rebuilt carb has worked great ever since.

[LickskilletM37]

Thanks ZG

Sounds similar to my setup. The guy who had it before me tapped directly off of one of the two batteries with both the hot and ground going back to the same battery to get a nominal 12+ volts at the pump. The positive side has a toggle switch. Not a very good setup, and something that I plan to remedy at some point. With the top off of the carburetor I can see the float raising up and shutting down most of the flow. If I pull up on the float a little, it will shut the flow off completely. It seems like it has to be one of three things: too much pressure, a bad valve, or heavy float. I just replaced the needle valve a year ago, and I think it has had this problem since I bought the truck, before and after I rebuilt the carb. I may remove the float just to check that it doesn't have any gas in it weighing it down, but I don't think there is anything wrong with it.

Chuck

[ZGjethro]

Soon after you figure out your float level issue, you should deal with the 12v pump. If you run it too long, your batteries will become unbalanced and it is hard on them. The only thing on my truck still 12v from when I bought it from the fire department is the fire siren, but it sees very short and sporadic usage

[LickskilletM37]

Ok, I attached a pressure gauge near the carb and it is putting out about 2 psi, so the pressure is not causing the problem.

With the lid off the carb, it will fill it to the top of the bowl. If I then shut the pump off it will drain down to about 3/8" from the top. If I then turn it back on it will then hold the pressure without rising to the top of the bowl.

Chuck

[Cal_Gary]

I recall the fuel pump pressure should be 4.5 to 5.5 PSI. I also had overflowing float-bowl issues. Mine ended up being just a smidge off on the float height. Once I dialed it in, I had no more overflow issues.
Gary

[LickskilletM37]

I'll check that next. I measured it when I rebuilt it, but I could have screwed up. I didn't it was that critical that being a little off could cause it to overflow.

[Cal_Gary]

Me neither but it sure makes a difference!
Gary

[LickskilletM37]

I found the issue with the needle valve. There was a tiny sliver of fuel hose stuck in it. It works now, but the motor doesn't run much better. It's still missing when I apply throttle and the let the rpm rise. I set the float level by letting the electric pump fill the bowl and then measuring after the needle valve closed.

I'm going to set the ignition timing next and see if it helps any. I'm not expecting much improvement from that though.