Hesitation on accel - '74 w/ Webers & MSD

[John Mullins]

My '74 engine has been converted to Webers and I recently also upgraded to MSD Streetfire ignition + MSD coil.

Ran fine for 1000 miles or so, then began to hesitate sometimes on accel. Tach would drop to zero momentarily. Actually then died a couple of times just after pulling away from a light, etc. I could restart with a few cranks and continue though.

I checked all the connections and re-did the power and ground. Also re-routed the signal wire further away from the others.

Hasn't died again yet, but I still get the hessitation between about 1000 and 2000 RPM.

Any thoughts?

Thanks,

[Dave Colangelo]

Try a new distro cap and rotor and new plugs. I have had many hesitation issues that were fixed by this. Its a cheap job and may or not be the issue but its so simple its worth trying. The other thing to do is go in to your garage late at night when its very dark, keep the lights off, start your car and pop your engine lid. If the plug wires are bad you will see sparks from them grounding to the case. If this is the issue you have bad plug wires.

Regards
Dave

[Eagledriver]

If you still use points, they may need to be adjusted. After a few thousand miles the points assembly wears where it rubs on the distributor shaft. The points may no longer be opening enough.

-Andy

[John Mullins]

Thanks guys! I will focus on the distributor points and plugs.

[john walker's workshop]

what are your idle jet and venturi sizes? cams or stock?

[John Mullins]

Originally Posted by john walker's workshop

what are your idle jet and venturi sizes? cams or stock?

Embarrassed to say I don't know the venturi or idle jet sizes. PO bought the car with the Webers already installed. I've asked the owner before him but he hasn't provided info yet.

Cams and pistons are stock. It was rebuilt about 10k ago.

I'm getting about 10mpg and blowing smoke every time I step on the accelerator hard, if that helps!

Sounds bad, but the car actually runs well overall.

[lindy 911]

Sounds like lean fuel delivery off idle. You could have trash in the jets which is common. Does your set-up have a fuel filter? I'd check and clean it if it does, get one if it doesn't. The accelerator pump diaphragm could also be going bad. A bench top rebuild might be in order.

[Eagledriver]

If the tach is dropping to zero, the carbs are not the issue.

-Andy

[John Mullins]

Thats kinda what I thought too, which is why I started with electrical connections. Going to change the plugs, distributor cap, points and rotor as you suggested. If the problem is still there, at least I've eliminated that possibility. Not a bad $70 investment...

But I may have a carb issue too!