Carb tech?

[motorparts92]

Alright, have a bit of a problem with a carb im attempting to use. Its a holley 3310 was electric choke but missing parts, i bought manual choke kit for it..anyway, i put new gaskets, powervalve, etc in it just basic rebuild. I tested it on my 78 dodge truck with 440, and naturally both floats needed adjustment. Secondaries flood like nobodies business. i clamp off my rubber line going to them, and the primaries are perfect. was able to tune my idle, revvs up with no hesitation. as soon as i attempt to release my vice grips, gas instantly pours from the vent on top. I removed the back bowl, needle valve is new and shuts off as it should, float floats, all screws are tight and everything clean and tity. tried it 3 times, gushes every time. what it seems to me, is gas is getting in and running out the boosters keeping the float from floating high enough.. never had this problem before any ideas?

 

[lewtot184]

float adjustment is too high or dirt in the needle and seat. should be an adjusting screw and nut on top of the bowl.

 

[motorparts92]

took needle and seat out, perfect shape clean as whistle. float down well low enough to function. its something else messing with me

 

[hendo0601]

What kind of fuel pressure are you running? Carbureted vehicles dont like excessive fuel pressure. I would recommend no more than 5.5-7 PSI of fuel pressure. Install an in-line fuel pressure gauge to see what's happening.

 

[Meep-Meep]

Pull the needle and seat assy out and check the o-ring. I bet it has a slice in it or got messed up somehow.

 

[motorparts92]

Perfect o-ring... i took the metering plate and closely inspected it for any obviousu flaws...everything is super clean and right! i just dont get it :/

 

[Meep-Meep]

OK, then it's possible your float is hanging up on the inside. Is the float dented or distorted? Can you hear it rattle in the affected bowl?

 

[motorparts92]

No sir, but for some odd reason, while the carb is off the motor, if i tilt it i can hear a faint wheesing sound. every time its not level, which i also thought was strange. but no, i even changed floats with another one i had in a kit. still pushing up through that vent. and gas drips from the boosters for a good minute after shut off.

 

[Meep-Meep]

What about the bore inside the bowl where the o-ring seals? I have seen that area, which is usually perfectly smooth, get damaged somehow. Did you try bench checking the float bowl with low air pressure? I can also suggest that the part of the float that contacts the needle should align properly so the needle and seat assy o-ring is where it should be on its sealing area when the float is at the correct height. I have observed when the float is properly adjusted you will only see a few threads sticking up past that gasket surface on the bowl. There's not that much left to check!

 

[67 coronet]

make sure to look at the spot where the float hits the needle and seat to check for contact.that tab can get bent really easy and float will never close the needle.with bowl off and upside down the float should sit about level to close needle and seat.mostly you need to check if float is closing needle into seat fully.check with your finger with float out of bowl and then compair with float installed.you can check you needle seal by blowing air through the fuel feed hole while you close the needle with your finger.(float out of bowl)

 

[furyus]

This may sound strange, but years ago I was working on a 360 with a model 3310 750 holley and it did the same thing. Only flooded out of the secondaries, even when just cranking it. I tried everything until finally I swapped the floats front to rear and it stopped flooding. One float was brass and one was plastic. Can't remember which was which but it worked. Also make sure there's no gas in the floats(brass). Shake them.

 

[benno440]

bin it and buy a new one

 

[69 roadrunner]

you won't learn a thing by just buying new one part of the hobbie is to learn what works and what dosnt.

 

[Garys1969RR]

I would take the float bowl off, turn it upside down and blow into the fuel inlet thru a rubber hose. Should be no air flow until you turn it right side up and the float drops down and opens the needle valve.

 

[62MAX]

Is it one of the older 3310's with the secondary metering block or later with the metering plate ? If block make sure you have the correct block to body gasket.If plate ,which float ? As said above,the brass float won't work with plate,it extends into the bowl far enough to interfere with the float.

 

[BuckNeccid]

Yep, just put one back together last night Plastic float to the rear, brass float to the front. I was wondering about that, thanks FuryUS

 

[motorparts92]

Is it one of the older 3310's with the secondary metering block or later with the metering plate ? If block make sure you have the correct block to body gasket.If plate ,which float ? As said above,the brass float won't work with plate,it extends into the bowl far enough to interfere with the float.

That was the problem. runs like a champ now! thanks a million! ima learnin!