The Stovebolt Site Forums The Shop Area Engine Shop Non bolt engine question.

When I got my jeep, I needed to install the tranny and do some brakework etc. etc. and now I need to do something about the smoke.
I've run it occasionally and it always smokes.

I start it with the choke full out and the smoke is pretty heavy. After warmup, I put the choke in and the smoke reduces quit a bit but when I accelerate, it comes right back.
The smoke is gray to dark-gray, the plugs are black.
I have a new Solex 1 bbl.
Any thoughts or troubleshooting procedures would be greatly appreciated.
BTW: its the original 1945 flat 4.

The only thing I can think of is that the mixture is off.

Either that you've got oil leaking into the cylinders, but that doesn't usually reduce under acceleration.

Is it "running too rich" (black/grey) smoke, or is it "burning oil" (blue) smoke?

It seems to be gray.
There is a single screw on the carb.
I can't figure out how to adjust it.

UPDATE: Another website says to restrict the fuel pressure to 1.5 to 2 lbs with an inline fuel regulator.
Does this sound right? Ever checked your fuel pressure?

Actually, that fuel pressure regulator does make some sense. The fuel pump may be producing enough pressure that the float can't keep needle valve in its seat, which would give you the effect of a rich mixture, especially off idle. Has the fuel pump been replaced?

It's the stock mechanical fuel pump, but it is a new carburetor. The old Carter model 539S, AKA type W-O, leaked like a sieve and my rebuild failed. I purchased a Solex, as used on VWs, which was manufactured to fit the old jeep manifold. I'm wondering if the old Carter could handle higher pressure than the new Solex.

Interesting. Which Solex for what engine displacement?
Your transition circuits and enrichment circuit would likely be very different going from the VeeWee motor to the duke. The vacuum at various engine speeds will be different. Both of them use some neanderthal intake designs, which levels the playing field a bit...
I take it this was a kit someone produces to work on your Jeeper. Hopefully that's all worked out.
Playing with the float level, and being able to "See" what's going on from idle to midrange, and off to WOT at varying engine speeds requires an O2 sensor, a vacuum guage, and a tach. There are variations from one engine to the next, so making a swap of this sort generally requires some extra attention. Not plug and play.

I have the aforementioned monitoring devices installed on a 4 bbl rig that neither OEM ever intended to be mated to a small inline six. It took many tear-downs to get it right. But once it was right...

I've never seen a carb come out of a box that was optimized to fit anything. Well, maybe a weedeater...
Fuel pressure can play some nasty tricks on you, If they are calling for ≤2#'s, and I would think the original mechanical delivers considerably more, you will need to rectify that. A good quality fuel pressure regulator should help. Measure the output pressure of the pump. If your overpowering the float, the increased float level will mess up your mixture, and result in your symptoms.


2¢

CJ

C10
A little history.
It's a 1945 GPW. It's the original L-head 60 horse engine. The Carter carb went T.U. and I purchased a Solex 1bbl which is manufactured in India to use on the jeep licensed Mahindra CJ3.
I bought a pressure regulator, but now the points have given up the ghost. It's like playing whack-a-mole