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I have a Solex carburetor on my M-38 and also an original carburetor that would need a re-build. In general, is there a carburetor that provides the best performacne on these engines, other than the Solex or the original? Just looking for some input on what others are using and their experiences.

I started with a carter WO early in my project then found a nice
carter YS637 and am now running it. I like the YS637 because its what's
sposed to be there. As far as performance, my M-38 runs like, you know,
a willys flathead 4 banger, and for me, it dont get much better than that.

The YS637S is the best all around carb available for the M38. The WO is second best and the Solex is a distant third bandaid for folks who can't properly overhaul the first two. Unless you improve air flow, both intake and exhaust and bump the cam there is no benefit to using any other carb. A throttle body with electronic management would be the ultimate stock L134 fuel distibutor. Vic Hickey took the L134 as far as it could go in the 60's with dual carbs, split intake, split exhaust, raised compression and a lot of cam profiling. There are simply no new production performance carbs out there to compliment a 1" flange small intake manifold.

If you begin your search for a YS be advised that ONLY the YS637s
is compatible with the L-134. The mounting flange of the YS950 is
indexed 90 deg off compared th the YS637s. You'll typically have
more trouble locating a YS637s and pay more for it. My 2 cents.

You say you also have an original carb-is it a YS637s?

I also have a Solex on my M38 and it runs well - no problems or operational issues from right out of the box. But on the self is a basket case WO and a basket case YS - the original carb will get a rebuild as soon as I can get to that project. I want to get the M38 back to its original condition and equipment, a process to be sure!

Yeah, my original carb is a YS637S. I'll plan on rebuilding it and putting it back on. In the meantime the Solex seems to work ok. Thanks for everyone's input.

As a sidenote i've replaced worn-out MARVEL-SCHEBLER updraft
carbs on early JD and Ford 8-N tractors with Solex and they ran
remarkably well...

Sorry I want also to ask which carb in the m38 has better fuel economy????

That will be a tough question to answer honestly and with some solid road test data to support. There are simply too many causes of high fuel consumption on these old jeeps to be able to present an unbiased technical report on which of the three carbs delivered the best. Mainly because there just isn't anyone out there who has taken the time to rebuild correctly one of each and road test then under identicle conditions on the same jeep.

Keep in mind when a guy removes his tired YS637S because he isn't happy with it's performance and then installs a new or remanufactured WO or Solex and perormance and economy improve then it is likely the improvement was because the YS637S needed to be rebuilt.

wesk wrote: Dick Hickey took the L134 as far as it could go in the 60's .

Wes, do you have a link or other info about this? I tried a google
search and came up empty. A lot of us would be interested to
see what this guy was up to..

My BAD. Google Vic not Dick.

The best writeup I've seen on his time with jeeps was in an old HRM article. Covered a lot of his ideas, his jeep aftermarket parts offerings and the time he spent proofing the Dauntless V6 introduction for Kaiser.