View Full Version : engine poping on the gas?

05-18-2010, 12:56 PM
I got a question for u guys. I am having problems coming out of the turns getting on the gas. The problem is when I get in the gas coming out of the turns wide open my engine starts popping and kinda cutting out,and when it starts to build rpms it starts to go away maybe about mid straight away. Iam running a 4412 holley 2 barrel running a 408 yeah guys it is a Ford mild but not real wicked solid lift cam around not sure duration but lift on intake is 555. Running 110 octane fuel timing is locked and at 32 to33 degrees running 81 as jets had 75 but was running lean (number one was kinda white).No alt. good charged bat . Anybody care to take a stab at this.

06-10-2010, 10:27 AM
Sounds like it is loading up with fuel.That is a big jump in jet size from 75's to 81's and you probably have the wrong size power valve in your carb also.
Check your vacuum at the intake manifold with the engine hot at an idle. The power valve size should be roughly 1/2 of the engines vacuum. Example:
9"'s vacuum = 4.5 power valve etc. On even even numbers move down 1/2 size. Good luck.

06-18-2010, 10:14 PM
i have the same problem on my car with a keith dorton 4412 holley 500. i run a 355 kinda mild. 505 lift 150 domes. anyways i lowered my float level a couple times and it didnt help it. so i had a friend tell me that i need to put a piece of rubber hose on the bowl vent cuz its spilling into the carb when your in the turn. the hose will prevent the carb from loading up. try it and see what happens.

06-18-2010, 10:49 PM
That is way to much jet. I take it that it is a out of the box carb? You said that the plug looked a little bit on the white side did you use a plug light and see where the ring was on the porcelain of the plug? Just because it was white doesn't mean that it is lean. That ring will tell you if it is fat or lean. Have you checked the float level to see where it was? I would suggest that you check all of the above and you will probably find your problem.The jet that I would run in a carburetor that I would do for that application would probably be around a 76-78 depending on the rest of the motor that you have. But there again that is a different calibration then what you have now and a totally different metering block.


06-28-2010, 11:23 PM
Robbie you are on the money . I was way too fat on the jets . I actually dropped it down to a 79 and it it running like a sewing machine on steroids. Now if I could just get it to handle better .