Flooded Holley 750 Ultra Double Pump carburetor

[Cyty Slykers]

Need help with flooded carb. I have the Holley 750 Ultra double pump with the glass site bowls and the carb is flooding out...I can see the gas is at the top of the glass site but can't figure out how to let that gas out so that I'm able to adjust the site float.

 

[plymouthman]

Take a paint can cap to catch the gas and put it under the bolt that holds the fuel bowl on. Engine in car = drivers side for the front bottom right bolt. Passenger side rear bottom right bolt.
Just take them loose. Don't need to take them all the way out.
As u loosen each one fuel will drain out. Catch the fuel in the paint cap. To minimize clean up. Then tighten the bolts up. Adjust your float as needed

 

[Cyty Slykers]

You're talking about the idle mixing screws right? I was thinking about doing that but too wasn't sure unscrewing it off. Thanks

 

[plymouthman]

No. The fuel bowl screws. Their are 4 on each fuel bowl. At the very ends of the carb.

- - - Updated - - -

Loosen one of the lower screws and the fuel will drain out. I had to use the right ones because of clearance under the carb for the cup to catch the fuel.
I can't seem to get a pic to load right so if u want message me. 240 217 3885.
I'll send u a pic of what I'm talking about

 

[Cyty Slykers]

Ok I guess I got those screws confused with something else. What would cause the bowls to fill up beyond the half way point? The front bowl fuel was close to half way mark on the bowl and then for some reason it was maxed out.

 

[1wild&crazyguy]

The float setting is made by adjusting the nut & bolt on top on the bowl itself.
The clear site plugs are so you can see the fuel level and not have gas spilling out if say you had removed the original brass sight hole plugs 'and adjusted the fuel level to just crest the the bottom of the sight hole'
good luck

 

[Cyty Slykers]

1 wild I played around with the nt and bolt as well but the fuel that was already in the bowl didn't go down at all.

 

[1wild&crazyguy]

1 wild I played around with the nt and bolt as well but the fuel that was already in the bowl didn't go down at all.

Yes it's something you gotta do with the car running there by using up the fuel in the bowl and the level balancing out with enough adjustment. You should be able to get the fuel level 'below' the sight hole. If it seems like it's not making a diff at the adjuster, it could be the need and seat that sit inside the adjuster could be dried up and hard, you'll need a new one if so.

 

[bm02tj]

Or a float sank
If this just started remove float bowels and fix bad needle and seat or float

 

[plymouthman]

- - - Updated - - -

The bowl screw is circled that I used to drain the bowl bit you have to adjust the floats or it will just fill back up again.
I had an issue where it just kept letting fuel in and it had to go somewhere. My luck had it going straight into the crankcase. Engine was never fired. Brand new engine. I had to drain the break in oil and replace with fresh oil.
Took the carb off and found that it needed the needles and seats cleans and replaced. They were sticking.
After I rebuilt the carb a used a pan to check the carb for leaks and adjusted before I put it back on the engine. Then did my fine tune adjustments with the engine running.
Spending $100 bucks on oil is bad enough spending it twice was really bad.

 

[Cyty Slykers]

This is frustrating having to deal with this by it being a brand new carburetor. I adjusted the levels of the primary float bowl to where it was level with the bottom of the site bowl but within seconds of running the car it maxed out causing the car to cut off... sounds like the float or needle is stuck huh?

 

[kevin403]

What is your fuel pressure?

 

[1wild&crazyguy]

What is your fuel pressure?

Yes it's either a stuck needle and seat or like kevin403 pointed out, look at the fuel psi.
What fuel pump are you running?

 

[ckessel]

Defective needle and seat, float sunk from alchohol attacking it[ use brass floats], junk in fuel holding needle open, too much pressure from pump, brass floats with bad seam. Look at the fuel you collect from draining the bowls and see what left in the bowls when they are off. If you see a powdery brown residue, you have rust in the system. Rust will get by ANY filter made and give you a bad time with flooding, crappy running etc. Find some rare earth magnets and drop them in the tank, put them on the filter[ need metal one though] and that will stop that problem. I've dealt with your problem too.

 

[Cyty Slykers]

I'm unsure about my fuel pressure but I have a Carter fuel pump 5.5 to 6.5 max psi. I've replaced the fuel line from the gas tank, fuel neck filler, drained/cleaned the gas tank and put in a new sending unit a few weeks ago before starting having this issue so it can't be a rust or trash issue. Yesterday was really my 1st time putting it on the highway appx 60miles round trip. I didn't notice the flooding symptoms until I hit slower traffic which caused me to come at an complete halt and by this time I had driven appx 20miles.

 

[ckessel]

Might be a bad load of fuel from the station. Even though you replaced and cleaned stuff, you still get junk in from the station every time you pick up fuel. Tanks are under ground, moisture gets in etc. Thats why under ground tanks have to be replaced periodically. The old saying: don't pick up fuel after a new load has been dumped in or when their tanks need to be filled. This is when you are most likely to get contaminated fuel. If you have a way to test the makeup of the fuel and see if they snuck in some alchohol on you. My car has ongoing issues with fuel boiling in the tank and wanting to crap out after its warmed up. My neighbor had his truck blubber and die out on him after getting fueled up. Never had this happen before even in the hot summer, then whap. Problems. I'm guessing that we are getting more surprise additives in fuel that were never there before which is giving us issues. The new combo will be EFI with the pump in the tank, more clearance between the exhaust and tank plus some heat shields to help alleviate some of this.