On my 82F100 300 6 cyl on take off it jerks bad sometimes on take off other times it shakes violately. If I punch the gas to the floor it smoothest out. I'm thinking carb. It jerks back and forth bad. I know it isn't the clutch, that has a different feel all together when I don't let the clutch out just right. So I'm thinking either rebuild the carb or replace it since the throttle is loose and can't be fixed. Any ideas. Any input will be helpful. Thanks

 

What do you mean "throttle is loose"?

 

The throttle where the adjusting screws hit for the choke and fast idle. The arm is on a shaft at the bottom of the carb

 

If it runs smooth at idle, and revs up great in neutral, don't go messing with the carburetor.

To see if you've got a carburetor problem, I'd hook a vacuum gauge to manifold vacuum and see how it reads at idle, how the needle moves when the throttle is blipped, and what kind of behavior it exhibits when it's revved up to say 1500 RPM and held there.

Vacuum gauge should show a steady reading between 15 - 20 HG at idle, with minimal movement on the needle. When the throttle is given a short rev, the vacuum should drop almost to 0, then spike to a reading over the normal idle vacuum level, then stabilize back to what it normally is at idle speed. If revved up and held to 1500 RPM, the vacuum should take a dip, then rise up and stabilize at a reading higher than idle vacuum readings.

Jerking under load could also be ignition timing, weak spark, lugging the motor too low, etc.

Typically, when a straight drive is jerky on takeoff (after everything else is verified okay) it usually means the flywheel needs to be resurfaced and new clutch installed.

Over time the surface of the flywheel can get humps where the clutch has to be slipped on takeoff, changing gears, etc. Slipping the clutch too much can burn it up or cause the surface of the flywheel to become uneven.

 

Ok thank you very much I'll have the vaccume checked along with the timing. I have marked the pulley but can't seem to see the timing mark with the light. Must be doing something wrong. I'll have someone with more smarts than me. Lol. Again thanks alot.

 

Hold on a sec. Mine has a small vac leak somewhere but runs great. 86 300 6. If you have the granny trans my bet is its just the way your drivin. I do it every now and then myself. Bucks like a mule.

 

When I take off in the granny gear it takes off good then all of a sudden it starts jerking real bad I have to engage the clutch or I'm afraid it'll throw me thru the windshield . Then I let the clutch out hit the gas and it stops jerking but it also does it in second gear. I grew up on a stick shift, and don't ever remember this happening. I had a 68 ford galaxey 500 and it didn't do this. I checked the timing and got it set at 6 degrees btdc. Not sure if that helped haven't went no where to try it, I may drive round the sub division to c.

 

If you think your clutch is good, I would check your engine mounts......the rubber deteriorates & lets the motor rock & kick.