Engine Hesitation

[ttuurrkk1]

Hey All,
Recently bought a 71 F100 with a 460 Bigblock in it. It has a holley 600 cfm on it. I get brief hesitation from take off, it recovers quickly, but hinders the speedy take off non the less. It also occurs when I am at steady speed and I try to speed up...slight hesitation then recovers. I am new to this, and would much appreciate some direction as to what could be causing this.
Thanks,
Turk

[TNIceWolf]

The first thing i would do is go over the engine and look for vacum leaks. Then check the timing and tuning specs. And finally check the carb out for proper operation. if that doesnt fix it at least you have eliminated that many unknowns.

[colnago]

My first thought is the accelerator pump on the carb. If you take off the air cleaner and look down the carb throat, then pump the throttle, you should see a stream of gas pumping in. If you don't, then check your float levels. Also, adjust your pump to a heavier setting, if you can. My Edelbrock has three different settings available. I think the Holleys do as well.

Joseph

[Busboy]

Since he said it also happens during light acceleration, I would look other than the accel pump. Ported vacuum leak, if it has an old manifold with an EGR valve I would certainly eliminate it first thing. Yes I know, 71's didn't have EGR yet. Float level is easy to check and adjust on a holley.

[fastEdsel]

I chased down a hesitation on my 600 Holley for at least 6 years! First I found a vacuum leak on the vacuum advance on the distributor. Changing out the distributor helped a little but not the entire problem. I sprayed everything on it from ether to WD40, whiskey, weed spray, cat littler along vacuum lines but no difference. (I was kidding about the cat litter!) Fiddle farted with the accelerator pump till I had to pour water on the screws to cool them off from over adjustment, it was almost to the point of buying a new carb. BUT, my parts man son who just built a stroker 302, now a 347 CI said to try a new carb kit with the blue gaskets. So I did and what I soon discovered was an internal vacuum leak within the carb. So now sealed up and looking like a new unit, it runs as strong as any fuel injected engine. The difference was just shattering and my beloved '59 Edsel is once again a jewel to drive. Absolutely NO hesitation, the carb is right there, acceleration is still amazing from this beautiful FE high torque engine. So in closing I would highly suggest a carb kit overhaul. Take your time, work on a CLEAN bench covered with white paper towels, follow the instructions and I am almost sure your problem will go away. Good luck, keep us informed of how it turns out.