Got a issue with my 396 flooding. Before I had a bunch of engine work done the car ran with a new Holly street avenger 770. Didn't run too well but it didn't flood out. After the engine work I put the SAME carb and fuel pump (holly mechanical). Now the car runs very rich and will flood out. I show 7 psi on the fuel guage. I replaced all the gaskets in the carb, the power valve, and the needles/seats. Checked the floats and they are set ok and not sinking. I can start it for 30 sec and it runs like crap. Plugs black and flooding. Let it sit for a while and it will restart ok again for 30 sec. Air/fuel mix it to spec also.

The pressure holds after I turn it off. This carb sat for 2 years while the car was being worked on but I replaced the main parts as far as I can tell.

Did I miss anything on the carb ? Like I said it was working before all the engine work.

I have a brand new stock fuel pump I can put in if you think 7psi is causing the issue. But again, it does hold pressure with car off. Went down like 1 lb in 1 day.

Any ideas ?


Thanks

I've seen mine hold against 11# while I was playing with my regulator, and I have run 9# for awhile once when I thought I had a line size problem(didn't).

What kind of engine work?

hmmmm...

Did the engine vacuum change with the changes that you did to the engine? You don't list your changes. If the vacuum dropped your power valve might be wrong and opening at idle.IMO

I had the entire engine reconditioned. Bigger pistons so it's 60 over now. New 270 comp cam, hydraulic lifters. Slightly larger valves. Has a performer rpm intake. MSD 6al ignition.

Bringing this topic back because I am starting to work on the car again and need this to run. I am still having the flooding problem I had last year. I have tried a BRAND NEW carb, tried a fuel pressure regulator to no avail. It starts right up then idles good for 10-15 secs then begins to flood out. I have a vaccum guage hooked up and when I start the car it gets a soild 15psi and holds till it starts to flood out so I don't think I have a vaccum problem.

No backfiring or poping anywhere and it sounds fine when started.

Oil pressure is fine and engine makes no weird sounds.

What can I do next? tank/sender/all lines are new

I'm starting to get depressed

Zotch,The Holley 770 street avenger is a vacuum secondary carb.You mentioned when you start it it runs bad after 15 seconds or so.Try opening the choke butterfly fully by hand to let in more air.If it clears up,then the black choke cap may be too far counterclockwise.loosen the 3 choke cap screws and turn the cap clockwise to release some coil spring tention inside the cap to free up the choke butterfly to open fully sooner.:yes:

I will try that. If I turn the idle mixture screws all the way in on the carb I should get no gas into the carb at idle right? And if I still get gas flowing in what could that mean.

Thanks

I will try that. If I turn the idle mixture screws all the way in on the carb I should get no gas into the carb at idle right? And if I still get gas flowing in what could that mean.

Thanks
That would mean several things,the power valve is blown,float level is to high,bad metering gasket to carb body.

I will try that. If I turn the idle mixture screws all the way in on the carb I should get no gas into the carb at idle right? And if I still get gas flowing in what could that mean.

Thanks
NO idle mixture screws dont change the fuel . they change the amount of mixture draw on the idle curcuit

I would be blaming it on a bad power valve or , a sticking needle and seat.

I haven't touched anything on the brand new carb yet but the car is having the same exact problems as when the old carb was on it..which btw was brand new at the time also. So unless a power valve is going to possibly fix this I doubt anything is wrong with the carb.

Add more timing.