Hey all, My '53 Special with 263 Stromberg 2 barrel runs for 5 seconds then erupts fuel (this is not an exaggeration) from the fuel bowl then dies. The fuel comes out the vent and goes all over outside and inside the carburetor and is flooding the heck out of my motor... This happens with the motor running or the starter turning it and all the spark plugs out...I've tried two carbs and it still happens. I've tried several needles and seats. I've tried two fuel caps, and no fuel cap. I've had both carbs apart and they look fine. It started happening last Friday. Could the fuel pump be the culprit? Supposedly the fuel pump has a diaphragm and spring design that slows down fuel flow when the needle in the carb is shut...could this go bad? Any ideas...for once I'm totally at a loss! PLEASE HELP!!!!!!!!!
Really sounds like too much fuel pressure. Better check what your pump is putting out. If your Stromberg is an EE-1 or EE-7/8, they don't like anything over 3 to 3.5 lbs. of pressure. Matt
Quicky test: after it erupts, disconnect intake side of fuel pump to render it inop, put output line into a container and spinnit over to empty pump, reinstall that second line so you don't have anything remaining squirting on your engine. Go have a cup of coffee while engine airs out the excess fuel, then start it up. Car will likely run fine for a minute. Next--this could be either excess pump pressure (test with gauge; any friends with older tools lying around likely have one of the cheapy vacuum gauges that also can test low pressure pumps) OR a good pump blowing through a stuck float needle valve or a valve left open by a sunken float. Incorrectly set float also a possibility if anyone has just been messing with carb.
OK, I tried a 3rd needle and seat, same problem...fuel pressure with the engine spinning and no plugs in never exceeded 3 pounds on my gauge, but proceeded to blow fuel out the hose and all over the place. Soooo, even though it defies logic, I ordered a fuel pump rebuild kit...it probably won't be here til next week...so I'll have to wait around for it. I'll update everybody when I fail miserably and push the car off a cliff...
Fuel pressure regulator..... Cheaper than the cliff option, unless you insurance is good . It sounds like your pump is delivering the fuel just fine, though possibly too high a pressure. Take the float out of the carb and submerge it in hot water, any bubbles and it's junk. Check float levels both closed and open everytime you take the float out of the carb. Flatman
Could be high float level, but my vote is excess float drop. What happens with excessive float drop is that the float tang is pressing sideways on the needle instead of up and the needle stays down when it should be up and closed. A somewhat common problem on AFB's, but it can happen with many other carbs. Motors Manuals usually have the float height setting as well as float drop setting.
Everything mentioned has been tried so far, even the screwdriver! ...I'll check the float drop, but this is a problem that happened all of a sudden...it ran fine for several hundred miles, then started pushing fuel...anyone have specs on float drop for a '53 Stromberg AAUVB-267 (7-90B)?
All I can find for that carb is the float setting, no drop setting listed. 5/64". It does note the measurement is "Above Vertical Guides" whatever the heck that means. There is a fuel level setting. 21/32". the note on this says "Without gasket @5# pressure. This info straight out of the Motors Manual for your carb number. Nothing was listed for float drop, but a little common sense will tell you if it's excessive. The shape of the fuel bowl as well as depth may or may not allow the float to come down too far. What happens if it does come down too far is the needle drops too far down and the tang is pushing sideways on the needle and things get locked up. Measure float height with the air horn upside down. Measure or check float drop with the air horn right side up. Don't overlook the possibility of a leaking float that's either drowned or riding too low in the fuel. Remove the float, give it a shake and listen for fuel rattling around inside. If there is a leak, once the fuel is removed, solder up the brass float. Take a look at the float's needle tang as well. Worn? Rough? That would limit the minimal sliding the needle does on the float tang. Any chance the tang is limiting the needle valve's operation by it's angle?
I don't think so...I check the float operation every time I put a carb together...I make sure it swings freely from seat to open...this one seems to be working perfectly...oh, and the float is floating, I checked that out too. It doesn't seem like it's dropping excessively either. I'm literally stumped...I think I may have a 1 in a million problem. I'm going to tear the fuel pump open this weekend and look for stuck valves or maybe a woodland animal that's hiding inside and spitting fuel out. Who knows? I'm literally stumped!
aaron-what is the engine temp when this is going on? hot? cold? if it is just "always", stick a 6.00 dial type fuel guage on it. -oh yeah,does your fuel pump have a return line on it? if yes, check the return line for kinks,make sure it is clear, and finally, make sure it isn't too close to the exhaust-the return may be vaporlocking and forcing fuel back into the pump-which would stuff it into the carb. I can't imagine the stromberg being so thisty it would require a large volume pump. also-make sure you have the choke hooked up properly-it has a cam to raise fast idle, but it also enriches the air charge-if it got wonky on ya, there is a possibility it could be caused by the choke assy. the fact it is doing this makes me lean towards the rest of the car. check your lines,pickup in the tank, and filter. a little bit of trash goes a long damn way in a needle and seat.-I once fought the same peice of aluminum trash trapped between my carb and fuel pump for about 3 hours-it would float into thre carb,hang the needle open and flood the motor.by the time I got to the line, the fuel in the carb would heat up and backflush the line, so I would pull the needle and seat-nothin.re-install it, car would run great for a few minutes, then second verse,same as the first. additionally, how hot is that carb getting? fuel boils at a really low temp (compared to water)-so if it is boiling over, you may need an isolater of some type to chill that booger out.
Try taking the top off the carb with line connected and put it over a large coffee can. That way you can look at the whole system as it would work on the car. Spin the motor and see if lifting the float by hand will shut off the fuel. If you have to push hard at all, it's not going to seal. If you can tee in a gauge, see what happens to the pressure as you shut the needle. Don't hesitate to try a second gauge. They're typically not very accurate at low pressures like that... WARNING...if the brass seat insert has "windows" cut into the side of it, be careful! You are going to have fuel everywhere...
That's a good idea...the float is part of the lid, so it could be interesting (probably a 2 person job), but I'll give it a shot. The seat does have a window, so I'll be chewing on gas probably. Thanks for the tip!
Have you tried an alternate fuel supply tank to see if the pump is getting a constant supply of gas? If the supply is partly blocked,you can get surges to the carb.
I had the exact same thing happening with a Ford 94. Gas was puking out the vent hole over the accelerator pump. Took it apart and found the needle valve for the accelerator pump passage was missing. Also found the float level out a bit (not much though) I think intake air was blowing back and coming up the accelerator pump. I don't know if your Stromberg has the same arrangement, but the problem sounds similar. Did you try putting the float in hot water? If the carb worked okay until recently, there must be something that went south, stuck, etc.. Flatman
Haven't tried an alternate source of gas, but it's doing it with the motor turning by the starter...so I don't know if that would be an issue...Flatman. The accelerator pump uses two check balls and they're in too. I have put the float in water and it's fine.
Well, it seems it was indeed the fuel pump...weird. If you've never rebuilt a combo fuel/vacuum pump, you owe it to yourself to try. Just kidding--it sucked (at least the vacuum side Ha ha). The only problem is a leak from the fuel filter to carb area...I didn't run it long because I need to change the contaminted oil...but knock on wood...I hope it's fixed! Thanks for the suggestions. Oh, the only problem I found on the fuel side was a bad outlet check valve...
The Jalopy Journal
