louie

Hi, new member here, Great forum, Problem; My 911 has the 6 Weber carb set up, it developed a skip or sputter when changing to a higher gear under regular throttle, it runs great under harder pedal. My mechanic thought it was a carb problem and rebuilt them completely. Still has the same exact problem. He noticed a lower than normal fuel pressure, checked this with another gauge, confirmed and replaced the pump and regulators.Still has same problem after all this. He and I are stumped, and would appreciate all input, thanks Lou

DGaunt

Just to get this started, as I understand it, webbers run best at full throttle, anything else is gravy...The carbs transition from the idle circuit @ 2,500 RPM and things can lean out at that point. I think PMO has a mod to fix that, but I have no details. the other place to look is the ignition system. It can cause problems in the transitions if not in tip top shape. Have the plug wires been changed?

Hope this helps start off the debate, and good luck

louie

Thanks Dave, I just talked to my mechanic today about checking the wires and coil. For some reason he is hard headed about doing this as opposed to working with the fuel system. I think I got my point across to him. Again, thanks, Dave.

Steve Weiner-Rennsport Systems

Louie:

Those carbs will give you & your mechanic fits unless the float levels are PERFECT at 3.5 psi of fuel pressure.

Further, the idle jets can clog up incessantly unless your tank is free of any rust, your air cleaners are effective, and your fuel filter is effective. When the engine runs poorly at anything but full throttle, this is a key sign that the idle circuits are dirty.

Webers (and PMO's) are very very reliable and trouble-free only if they are setup properly.

louie

Thanks, Steve, We will double check all of this.

louie

The new coil fixed it, thanks to everyone for the response. My mechanic was slightly embarrassed.