Hi I have a Holley flooding problem, my motor is a std. bore 454, GM dual plane intake, open chamber rec. port heads 9 to 1 compression, a 550 lift 235 duration roller lifter cam, roller rockers,I have a Holley 780 dual feed vac. secondary carb 3310-1. this carb has two metering blocks and two power valves and one primary acc. pump. The problem is when the motor is running on the choke high idle about 1500 rpm gas is pouring from the pass.side primary booster, I opened the choke flap while the motor is running and fuel continues to pour when I slow the motor down to idle (700rpm) the fuel stops. Also last night after driving 50 to 60 mph for 30 miles I parked my car in a heated garage, 1/2 hour after shouting off the motor I'm getting gas dripping off the primary booster (pass. side), I hear gas squirt from the squirter nozzel I think and then a hissing sound coming from the primary area of the carb, I put my finger over the primary vent tube and gas shoots up about 2 inches out of the two small bleed holes on either side of the squirter nozzel, then the hissing stopped.I have put in fuel system cleaner in the tank, change my fuel filter, changed the primary needle & seat twice, I lowered the primary fuel bowl level just below the sight plug. I have 7 1/2 psi fuel pressure. I don't seem to have any problems with the secondary side of the carb. This is a rebuilt motor with a different cam and a old carb could this problem be a primary power valve that is too large? I have a 10.5 primary power valve and a 8.5 secondary. I will check intake vacum tomorrow.Any quick comments would be greatly appreciated as this is my only car right now and is not running too well. Dave

[This message has been edited by dsr (edited 10-31-2002).]

[This message has been edited by dsr (edited 11-01-2002).]

[This message has been edited by dsr (edited 11-01-2002).]

You have the same carb that I do. I would start by getting a Holly master rebuild kit and rebuilding it. Soak all the parts accept for the plastic stuff in parts dip and blow them out with compressed air. then start troubleshooting any problems from there.

Will

Thanks for the input Will. Dave

Hello dsr, before you do anything else, grab a 5/8" box-end wrench and a stubby flat-blade screwdriver and lower the front float setting one (1) full turn clockwise. Start by loosening the adjustment nut slightly with the 5/8" wrench and then loosen the lock screw a half-turn while you hold the 5/8" wrench from turning. Now do just the opposite: hold the flat blade screwdriver in the slot of the lock screw stationary while you rotate the 5/8" wrench one full turn clockwise. Now hold the 5/8" wrench stationary while you tighten the lock screw with the screwdriver. I know you already said that you lowered the float twice but this sure sounds like a float that's too high.

I'm assuming that you have a stock type mechanical (block-mounted) fuel pump because the problem gets worse with increased rpm. The heat soaking into the fuel line after parking your car is causing the fuel to expand and 'push' fuel into the float bowl (which is set too high) and into the motor.

Hope that helps,

Louie

[This message has been edited by LouieHammel (edited 11-01-2002).]

Thanks Louie I'll try lowering the float level like you said today.And yes I do have the GM high output mechanical fuel pump. I get 7 1/2 psi. RPM does't seem to change the pressure any. Dave

[This message has been edited by dsr (edited 11-01-2002).]

[This message has been edited by dsr (edited 11-01-2002).]

My #3310 did the same thing. The secondary needle & seat was stuck. Just take it apart, clean it, put it back together, and set your float level.

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Mike Newby

69 Chevelle 355/TH200-4R
97 Grand Prix GTP
64 Chevy C10 Pickup
79 Suzuki GS550

Do you have the return line hooked up to your gas tank?

Louie I lowered the primary float level one full turn just like you said. This seemed to help, while running on high speed idle with the motor warm there wasn't any gas pouring off the booster.I just had the car idling in the garage for 20 minutes. When I left for work tonight the motor was cold, I pushed the gas pedal one time to set the electric choke, the car started right away and fuel was again pouring off the pass.side primary booster. With the motor running on fast idle I pulled open the choke plate and the flooding stopped, still running on high idle. This is an improvement as the flooding would not stop before until the rpm dropped. I think I'll try and lower the primary float by another 1/2 turn tonight before I head home in the morning. I didn't get too much time for road testing the car today, due to our first snow fall and needing sleep (I'm working night shift) just drove it to work tonight. I'm off for the next 3 days and will get a chance to check intake vacuum. Dave

[This message has been edited by dsr (edited 11-01-2002).]

Xtreme70SS396: No there is not a gas tank return line, the car is a 1964 malibu. I ran it this way for 40,000 miles with out any trouble, but have since rebuilt the motor with a different cam & lower compression and went from a '66 396 chevelle GM mechanical fuel pump to 2002 GM high output big block mechanical pump. Dave

Georgia69:
The secondary needle & seat was stuck.

Hi Mike I have changed the fuel filter and the needle and seat 2 times with new parts. Dave

Glad you found your problem

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Mike Newby

69 Chevelle 355/TH200-4R
97 Grand Prix GTP
64 Chevy C10 Pickup
79 Suzuki GS550

[This message has been edited by Georgia69 (edited 11-04-2002).]

Sorry, just checking in again- problem resolved with float level? If not, try dropping your fuel pressure down slightly, to 7 psi & see if it helps out. You may be forcing fuel past the needle & seat, but I know many here use 7 1/2 psi without trouble. From what I've read, that can sometimes be too high.

Xtreme70SS396:
Hi I think I've got things fixed between lowering the primary float level another 1/2 turn and backing off the choke adjustment on the black platic cap about 1/4" past the scale on the cap. The motor runs much smoother when the choke is on. I didn't get much of a chance to try it as the weather is going down hill fast, it's snowing again right now and I have run into some trans mission troubles. Back to the garage for awhile. Luckly I just got my winter beater on the road today. I think it's time to do a few of those jobs around the house I've put off all summer. I'd like to thank you all for your help. Dave