Holley spreadbore problem.

[TURNA]

Did you have the same or similar issue when you where running the Q-jet on the stand?

If so the carb is not the issue.......

 

[Pontiac455]

With fuel only coming out of one booster, that would lead me to believe when u rebuilt it, u didnt use the proper metering block gasket. The gaskets have to match the ones coming off. Best thing to do is go on the holly site there is a tec page with the carb listing numbers. It gives all the specs and part numbers of gaskets metering blocks, plates ect. that came on the carb when new. Check the gasket numbers see if the right ones r installed. Another thing, before u rebuilt the carb what type of gaskets were on it? if it were the old black ones that are a pain getting off check to make sure when u were cleaning them off ya didn't plug n e ports. If everything up above checks out check the metering block and plate for trueness. PPl over torque the bowel screws and either warp the body or the block.

 

[MrSony]

I've always read spreadbore holleys were either hit or miss.

 

[DRIVEN]

Don't see why that'd be the case. Just a Holley with different venturi sizes. They still work the same as as squarebore.
Probably something simple.

 

[pontiacgp]

On that holley 4175 the mixture screws work backwards since it's an air bleed system, that is why I asked if he used a holley book to do the work. In is richer, out is leaner

 

[ElcoJoe]

Try starting it up, put hand over carb horn, if it revs go up its a vacuum leak. Or spray carb cleaner around bottom of carb, if leaking revs will go up.

If you can get a gauge an put it on a vacuum outlet should be 16 or up, depends on camshaft.

But honestly to me when l first read this l thought flood has issues that's why it's dripping fuel even after you shut it off because there is still limited pressure in the line until system equalizes. It's a Holley so there should be a top adjustment screw for the float. You can adjust it with car off but better when car is running threw the side site, adjust float until no more fuel comes out site hole if it's not the glass plug, if glass adjust it to the bottom of glass. This should atleast fix float issue enough to keep it running unless float has a hole. If you think float is issue, take bowl off and float and put float in a cup of gas and see if it floats.

If floats are ok then adjust side screws on side blocks to 1 3/4 to get it started, then with a pressure gauge attach to a vacuum line and get the vacuum to it's highest point by adjusting block screws.

If you can't get it to run trying any of this there is dirt stuck somewhere in the carb, most likely between needle and seat, an you might want to check that before you do anything else.

If you have a factory fuel pump it should work just fine with that carb, put you could put a regulator inline to check, cause there is no return line on that Holley, so carb has to eat what the pump gives.

Does carb backfire? Bad gas or dirt.
Not sure how long fuel stabilizer last, but a year is alone time.

Anyways l'm out of wind now so l hope that helps. The only other thing it might be is the pump in the carb and the adjustment that it might require. But that's another story, !

Thanks for the lengthy reply. Im just gonna take it off again and fool around with it a bit. Check the float, needle and seat, make sure there isnt any dirt floating around, and double check the torque on all the screws on gasket mating surfaces. Pump came off the 229 v6 that was originally in the car but some built up the little 6 popper. Its probably some cheap "performance" chrome pump bought from summit. Motor isnt backfiring at all either through the exhaust or carb. But like i said when i get the time ill have to make it a day project and fool around with it.

 

[ElcoJoe]

Did you have the same or similar issue when you where running the Q-jet on the stand?

If so the carb is not the issue.......

While the motor was on the run stand, we ran an electric fuel pump and as soon as we sent fuel to the carb, it just sprayed fuel from ever orifice. So my buddy gave me this carb that came off another truck.

 

[ElcoJoe]

With fuel only coming out of one booster, that would lead me to believe when u rebuilt it, u didnt use the proper metering block gasket. The gaskets have to match the ones coming off. Best thing to do is go on the holly site there is a tec page with the carb listing numbers. It gives all the specs and part numbers of gaskets metering blocks, plates ect. that came on the carb when new. Check the gasket numbers see if the right ones r installed. Another thing, before u rebuilt the carb what type of gaskets were on it? if it were the old black ones that are a pain getting off check to make sure when u were cleaning them off ya didn't plug n e ports. If everything up above checks out check the metering block and plate for trueness. PPl over torque the bowel screws and either warp the body or the block.

I dont exactly remember which color gaskets came off originally but i want to say they were the blue non stick gaskets. And I took my time and did my best to match up the new with the old gaskets.

 

[ElcoJoe]

On that holley 4175 the mixture screws work backwards since it's an air bleed system, that is why I asked if he used a holley book to do the work. In is richer, out is leaner

Sorry I must have skimmed past your first reply. Really? I thought they would be like every other holley ive dealt with. So when I said I richened it up a bit to get her to stay running I actually leaned it out. I used a mixture of my commom knowledge with holley carbs, acouple tips from some friends who have dealt with them (for alot of years) and one of the "basic how to" on holleys site.

 

[bob64]

Sorry I must have skimmed past your first reply. Really? I thought they would be like every other holley ive dealt with. So when I said I richened it up a bit to get her to stay running I actually leaned it out. I used a mixture of my commom knowledge with holley carbs, acouple tips from some friends who have dealt with them (for alot of years) and one of the "basic how to" on holleys site.

Holley has a website, go on there and they will tell you how to adjust up that carb. When you buy a new carb they come with instructions, but you got it used.

And yes it is in for more fuel. Got that carb on my Elcamino