so my friend jeff from my car club has been experiencing carb issues with is truck, this is what he emailed me a lil bit ago, if anyone can shed a little light on the problem or give a decent solution please let me know asap! we need this truck running by next weekend! "Well, I've been tinkering with it for a bit this morning, and I have the following problems: a) even with the fuel pressure regulator set down to 3 psi (the recommendation for that carb is 4-6), when I turn the screws up top that allow you to view into the float bowls, gas is shooting out the top. b) in park, it sounds fine at idle, but when I rev the engine, there's a lot of cracking and popping and backfiring. c) I tried to adjust the timing a little by rotating the distributer, but I was only able to make it worse (and then return it to the original level of roughness), but not better, no matter which way I turned it or how much. I talked to a guy at the parts store where I picked up the fuel pressure regulator. He said that running that carb with my electric fuel pump might have blown out the seals in the carb, which aren't made to take that much pressure, and now that I have the pressure regulated, the seals are still bad, and it wont work right until I rebuild the carb. I guess that would explain why it ran well for a day or two after I replaced the carb, but not after that. What do you think? The electric pump is the weakest one Holey makes. It's rated at 8 psi. The carb is supposed to run best at 4-6 psi. The guy at the parts store said the rating for the pump I have is generally a guaranteed minimum pressure, so it's very possible that it was putting out a lot more pressure than that. The weird thing is the edelbrock carb that I had on there is probably rated for the same psi, and it ran great with no regulator for a couple years. Maybe the seals were stronger, but eventually went out on the edelbrock, and the holley's just went out right away? -jeff"
You sir, likely need a new needle/seat/o-ring (or gasket). For example: What's happening to your carb is what would happen to this toilet if the seal in the while tower on the left went south. If it weren't for the black overflow tube, you'd have water all over your bathroom! Your carb HAS NO overflow tube. Where's all that fuel going? EXACTLY! ~Jason
Well the float level plug is on the SIDE of the float bowl not the TOP. The screw/nut on the top is the float adjustment. And you will get fuel out of there. Never met any carb "seals" to much fuel pressure cound blow out, over powering the float needle ,well sometimes. Get the fuel level set correctly then try a fresh set of plugs.
so far what i can come up with is floats set to high, and since its a holley possible a blown power valve, does this sound about right?
my bet is a piece of grit in the needle valve. it ran good for a couple days, then the grit got in there and is not letting the floats close the valve, therefore the electric pump is just pumping away, flooding out the whole darn thing. That's my .02 Clean it, clean the plugs, put in a fuel filter, then try again. cheapest answer.
Grab a plunger, Mario! LOL! Hmmmm... maybe tapping it with a rubber mallet? No, I'm NOT kidding! Hey, I'm a Stromberg/Rochester guy here... ~Jason
ok, the prob is that it did the same thing with the edelbrock it had in it prior to the holley. but its worth a check! thanks guys, keep the suggestions or possible solutions comin. any and all help is much appreciated!
Yeah, probably a little piece of junk like a piece of a gasket is stuck in the needle and seat, allowing fuel to keep blasting in. Unless the float adjustment is just way off. It could just need a new needle and seat. A hole in the float could cause the float to sink constantly, which would keep the needle and seat wide open all the time too.
If this problem keeps happening with different carbs, it could be the fuel tank is all gunked up with some flaky crap that keeps winding up stuck in the carb's needle and seat. If crap gets into a fuel pressure regulator, the regulator can suddenly get stuck open and not regulate too.
Could be, my 66 Galaxie had a 2bbl (motorcraft) 390 setup. It had a power valve that would blow out whenever the engine had a good backfire. It would run similar to what you described above until I replaced the valve. I know we don't know eachother but if you need help rebuilding it before RCR you can bring it by, I've been through a few of them.
Its a holley, The proper way to make it run right is to smack it with a hammer until it is beat to hell, Or thats seems to be how everbody else fixes them.
Right.. if you've had a backfire on a Holley, the power valve is shot....and leaking fuel into the manifold,causing all kinds of problems.. Change the power valve(s). Set the fuel level to the bottom of the sight plugs(the clear plastic plugs should be used for tuning only). Make sure you have no vacuum leaks. Idle should be set by the highest reading on a vacuum gauge. Timing could be set using a vac. gauge also, but watch for bad(camel piss) gas).
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