Carb rebuild - fuel flowing out of mouth - ideas appreciated

[foothilltom 33]

Howdy gents,

 

A friend of mine (who, believe me, is much more of a gear-head than I) volunteered to rebuild my 2V carb (it's a 2150, much like the stock 2100 but apparently has some altitude compensating gizmo) and I just put it back on the coupe last night. The carb absolutely needed rebuilding as it was completely choked with gunk after 7 years of sitting in the side yard of the previous owner.

 

In any case...the engine fired right up, sounded mean (still just open headers), and promptly flooded and died. From my vantage point, I could see gas flowing up out of the mouth of the carb (like a volcano) and getting all over the manifold. I can't tell precisely where the gas is coming from as I didn't feel comfortable with that much gas and potential for a fiery end of the evening.

 

I've googled quite a bit and I haven't been able to identify a strong suspect. So I turn to my brethren (and sistren?) here to see if anybody has had such a problem and perhaps could offer up what I could look for.

 

This friend of mine has been so helpful, I'm trying to bootstrap myself and cut back on how much I bug him, but this car isn't going anywhere until I resolve this.

 

Any info is MUCH appreciated.

Tom

[69RavenConv 286]

I would guess either the float or needle valve. The fuel pump sends gas into the bowl of the carburetor; inside the bowl is a float that rises and closes a needle valve when it's full, preventing more gas from coming in. If the float isn't floating (or isn't set right) or the valve isn't closing, you get overflow like you're describing.

 

Are you sure it's coming from inside the carb? Because it could also be a loose fuel line or hose clamp, etc.

[69RavenConv 286]

I found this site poking around the web, maybe step 8 applies???

 

http://www.hurtle.com/cars/mustang/fixes/carb/

[foothilltom 33]

Hey 69Raven, thanks very much for the info. I'm 100% sure the gas is coming from the bowl. I had my boy start the car today and I watched carefully (with extinguisher in hand). The gas just roils out of the mouth after a few seconds, so it sounds like the first thing you described. There is no fuel at all leaking from the front of the carb. Fuel filter connection is dry as a bone.

 

I'll take a look at that link and see what I can do!

 

Thanks again,

Tom

[69RestoRod 10]

Sounds like either the float is bad or not set to the correct level. There may also be something under the float needle preventing it from seating. Take the top of the carb off and inspect the float first. Carefulley remove the float and the attached needle and see if the float has fuel in it. This would cause it to sink in the fuel bowl and never close the needle. If not check the orifice the needle comes out of for debris that may prevent the needle from seating. If neither of these are the culprit reinstall the float and needle and check the float level. The rebuild kit should have come with a small L shaped measuring device. You put the device in the fuel bowl and it should give the correct height of fuel in the bowl that the needle should be closed on. If you don't have it anymore you can bend the tang on the float in small increments until the fuel bowl stops overflowing. Too much will cause fuel starvation, and too little will cause it to overflow.

[foothilltom 33]

You were exactly right, gents. My pal is a GM guy and he'd never quite seen a float/needle/seat arrangement like on this 2150 Motorcraft. After much messing around and following the leads here, the boy and I actually saw that the little "hinge pin" that the float pivots on was not "locked into place" at all and the lid of the carb didn't press it into place either. We noted that the little coat-hanger-gizmo that keeps the hinge-pin from shifting back and forth needed to be also attached to the seat itself -- locking the whole assembly in place.

 

I'm probably not explaining this well, but the bottom line was the pressure of the fuel was simply blowing the pin right out of the seat despite the proper setting of the float. When we locked the assembly down with that little wire gizmo (it wasn't obvious to us for sure), all was well, she ran w/out barfing gasoline and we were giddly like school girls.

 

So, in short, our rebuild was a bit sloppy and we learned a great lesson in fluid pressure. Oh, and I singed most of the hair off my left calf. That's a story for another time. It was a hoot.

 

Thanks very much for your help, gents. Another good ending to a good mystery.

 

Tom