Is that a '56 235 car engine? With out going back thru all the past threads
we, or at least I don't recall which engine you've got in your truck Lem.
And without knowing exactly what you've used for an air cleaner it's hard to
come to any conclusion.
Every carburetor that I've tried on my '50 216, which are several
meticulously rebuilt Rochester 'B's and a couple of W-1 carters, have left
me with the stumble on acceleration. This was true without an air cleaner,
with the spark arrestor using a paper filter, with an oil bath filter, with
the original engine and after a complete engine rebuild. You will hear some
experts tell you to jack your timing way up till it's pinging but I'm not
an advocate of that. Set to the ball was the best performance that the
engineers determined over tens of thousands of hours of dyno testing and
the way millions of Stovebolts were designed to run, so that's where
I've always set mine.
The smoothest engine performance I've been able to accomplish is by adding a
small amount of choke, which does eliminate the stumble when I apply
throttle when I start off or hit the throttle to accelerate. This is true in
all of the previously mentioned configurations. And this suggests to me
that the engine is simply running lean. Why would it be running lean if the
timing is correct, and the carburetor is correct and is metering the proper
mixture? The conclusion that I've arrived at after 10 years and 15,000
miles is, it's the fuel that we're using now a days. It's doped with
alcohol for one thing and who knows what else has been done to the refinement.
Todays engines with their computer dictating mixture and timing many times
a second can compensate for the fuel it's drinking, the simple Stovebolt can't.
In the ten years that I've been on the Stovebolt.com forum and many other
forums, I've yet to hear any other valid solutions.
I doubt very seriously if your new exhaust has anything to do with the
hesitation. If your air cleaner is choking down the engine a little that
may account for the reason the stumble is gone now. The original air
filters/spark arrestors offered very little restriction to air flow compared
to the paper filters, that's why generally the air cleaners that use a
paper element are quite a bit larger than the old oil bath or oil soaked
mesh filters.
Denny Graham
Sandwich, IL
Last edited by Denny Graham; 10/26/2015 11:07 AM.
