Motor breaking up

[Homey]

I have been chasing an on off issue this year with no true smoking gun found. Most nights motor purrs fine all night. Not one hiccup. But on a couple of occasions motor sounds as if lugging when coming through and off the corners. After first episode i had carburator gone back through. Seem to have gone away although my guy said didn't really see nothing. Then it showed up again last night we raced. Almost as if flooding through carb. Gone through all wiring, had ignition boxes checked, carb gone through, fuel pressure doesn't reflect lose or spike (alcohol). Battery is Red Top Optimum shows 12.4 to 12.5 volts while this is going on. Any suggestions or passed experiences with this BS?

[z40chief]

IF running a KSE pump try taking a 17" piece of rubber hose and loop it to the top of primary vent to the secondary vent (if the vents are angle cut on top)on carb letting any excess fuel dump into the right side of filter instead of engine. Make sure to cut a 1/4 x 3/4 or so window in hose to let vents work and dump the fuel in the air filter. This worked for me when on alky don't have the problem when running gas with a KSE pump. Good luck.

[hpontap]

What type of fuel regulator are you using and on the nights it acts up, did you buy fuel at the track or did it come from the same barrel of fuel that ran good before?

[7uptruckracer]

I stumbled (no pun intended) upon this and while I should have known because its in the manual I have honestly never paid attention. On some of the bypass regulators you have a pill for idle fuel PSI which is 2-5 psi yours can be different for alky then you have your other set screw for your racing fuel psi. DO NOT set your float at idle with these because you will be setting it to the lower PSI and if you get a fuel pressure spike it will flood and it might not have a chance to clear it. They put a pill in these regulators for idle I was told to change the pill till i get 7psi at idle yours could be different for akly, set my floats, then change my pill back to my idle PSI that sets the float level, Then I was told to get a rough starting point bring it to 3,000 RPM and check PSI there make sure its where it should be for your akly, Then run it ON THE TRACK an make sure mid straight away you have to correct pressure if not tweak it. Might not be your issue but more info to consider

I have been chasing an on off issue this year with no true smoking gun found. Most nights motor purrs fine all night. Not one hiccup. But on a couple of occasions motor sounds as if lugging when coming through and off the corners. After first episode i had carburator gone back through. Seem to have gone away although my guy said didn't really see nothing. Then it showed up again last night we raced. Almost as if flooding through carb. Gone through all wiring, had ignition boxes checked, carb gone through, fuel pressure doesn't reflect lose or spike (alcohol). Battery is Red Top Optimum shows 12.4 to 12.5 volts while this is going on. Any suggestions or passed experiences with this BS?

[JustAddDirt]

check vent in fuel cell
make sure there is no moisture in dist. cap.
make sure the dist. cap electrodes are clean as well as the little nub that the rotor button spins on is not flat, still has a crown on it.
as well as all other items listed above