As some of you know, I'm driving my truck now, and its running nice with the exception that sometimes it sputters a bit. Not quite a back fire, but a sputter-like coming from the carb. Do you think it's running too lean, or do you think I should try rebuilding the carb? Or might it be something else?

 

Check timing first.

 

Timing, idle and advance. Carb kits are cheap and easy. Good flow from accelerator pump? If it has not had it, a good complete tune up may be in order. How much tune up history has been documented? How about the valve train, oiling and adjustment? Compression?
These things can be smooth but not like FI.

 

I probably should have added that tune up, including valve adjustments, coil and electronic ignition have been done.

 

Do you guys think a bigger jet would help?

 

What jets are in it? How do the plugs look?

 

The plugs are new. Don't know the size of the jet.

 

Is it sputtering at steady speeds, accelerating, coasting?

Without knowing what jets are in it, you can't really make any judgement on the direction to go on the carb. Holey jets to fit the 94/2110 aren't common so it is unusual to find anything but stock, IMO.

 

It only happens when I start to accelerate from 1st gear, I'm accelerating from s slow turn in 2nd. It's fine otherwise. I did notice the throttle shaft seems to have play, and appears to have a vacuum leak there. I'm assuming now I need to rebuild the carb.

Thoughts?

 

What hole is the accelerator pump rod in? Classic signs of a weak or inadequate accelerator pump discharge.

 

It's on the hole with the biggest squirt.

 

Too much can be just as bad as too little, put it in the middle hole (requires disassembly usually, so you can check your jets at the same time). Strictly speaking, you can change holes by pulling off the micro-sized E-clips holding the link on, but you're a better man than me if you can do that with the carb on the truck.

If you have your idle jets too lean, it may idle fine but starve for gas as flow increases. On flatheads it's generally better to be a little fat at idle to get the best performance at all low-speed ranges. You might try just opening them up a little.

 

The accelerator pump should deliver fuel with the slightest movement, usually it is delayed. Immediate reaction is more important than location on the arm (which hole it is in). If there is slop in the main shaft busing, rebuilding the carb will not fix a vacuum leak at the shaft. Like Ross said you need to read the plugs at minimum before doing any jet changes. All that being said, it sounds like acc. pump linkage adjustment is off.

 

We tried all of the wholes, and this is where it runs the best. I do see play in the throttle shaft. If I rebuild the carb, I will include the throttle shaft.

 

Hey FP,
Now you see what happened - You used the "done" word.
It's just bad mojo - as soon as you say that word all heck breaks
out & you look into a little problem & it grows & grows. You just can't use that word.

You are in the shakedown phase - I'm not sure we have ever made it out of there. We are currently working through why the passenger side door decides to open at the most inopportune times. Then on to the fuel guage fix, etc..

You'll get that "little sputter" fixed in no time! Good luck over there.

Ben in Austin
1950 F1