The Stovebolt Site Forums The Shop Area Engine Shop Engine sputtering

Hey everyone,
The 216 in my '42 3/4-ton special runs smooth and great in every way, except that if I push the gas pedal too fast, the engine sputters and coughs. It'll take as much gas as I want to give it, but only if I push the pedal down slowly and smoothly.
Is that normal for these old 216s, or is it something I can fix?
-Jon

Mine does that too, but it seems to work better after it's warmed up for a while.

Which makes sense... If you supply too much gas to the carb at once, it sputters (and if you're really unlucky, stalls). But after things have warmed up a bit, the carb is hot, which assists in the vaporizing part of the process, which will lead to less sputtering.

Or, I could be full of crap.

Someone will be along shortly to straighten me out if my theory is wrong.

the warm up does affect that kinda behavior, but so will the vacuum advance, or even a bad accelerator pump in the carb

Bill

Bikesmith and Brendan,

I think I'd have my carb looked at, if I were you.

My 216 doesn't exhibit that type of behaviour at all, and I'm even running on of those Rochester's that are always being trashed round here.

Probably the accel. pump but can be a low float level. Sometimes advancing the timeing a little can help.

Also if your manual choke wors properly u can leave it pulled out just a scootch till the manifold gets good and warm that is if it runs right after the engine is warmed up good...Ronnie

Just curious, my low pressure 235 runs better cold, an way better if I leave the choke out a little even when its really warm. I say I'm curious because I just want to know, I have a full pressure 235 going in it awefully soon with a T5 so it doesn't really matter. Thanks.
Colin

colin on last post,,,,dirty carb,,,low float,,,power piston sticky,,main jet a little small..doc

Here are a couple more pieces of info that might help pin this trouble down.
First, I didn't mention before that the carb is a Rochester B. I know, I know, but that's what was in there when I got the truck .
Second, I recently installed Fenton headers. The problem I described at the top of this thread predates the headers, but it got worse when I put them in, which is why I'm working on it now. I've seen vacuum leak suggested, but would that cause a problem only when I push the pedal too fast and leave the engine running as smoothly as ever otherwise?
Third, in another thread I saw that headers often require a richer mixture than stock exhaust, so I tried adjusting the mix. That made the engine 90% better, but I had to adjust it 2-3 turns out before it made a difference, and now I think I'm running too rich. And it still has a bit of hesitation on acceleration. Also, I notice it mostly in second gear. It barely does it at all in first. Is that significant?
-Jon