I was asked this question in an email and I want to share it here for all to benefit from.
Hey Wes,
Since you are the go to guy for M38 questions, I have a question I hope you can answer for me. I purchased a 1951 M38 all in pieces. It came with a bunch of old parts and some new parts. It also came with two carburetors...one is a Carter WO which I rebuilt and the other is a Carter YF with no numbers on it.
Since I won’t be wading in any water after the frame-off rebuild, can I use the WO carb on the M38 (assuming I have the top air tube for it, which I have 2-3)? The throat diameter is the same diameter as the manifold, but the YF is much larger. I’d rather not purchase the original YS-637S if I don’t have to since I’m also going to convert it to 12 v (non-original).
Sincerely,
Mark Ruschak
Well Mark, the WO will work ok with minor alterations to the linkage. You already have the stamped steel air inlet but I believe the diameter for the hose to the air cleaner is different.
Thanks Wes. Helps a bunch. I have a couple different air horns so I'll check them out and see what the dimensions are. I'll make it work as long as the carb will work. Last resort, I can pick up a solex from Kaiser Willy's.
Forgot to mention, my WO is a downdraft carb and does not have the 90 degree bend in the upper cover as seen in your upper two pictures...more like the WO on bottom two.
Hi Mark,
My M38 has a WO on it that came on it when purchased. It is highly
civilianized.
I recently sold a WO to another member who plans to put it in his spares
box for use when he goes high altitude climbing.
As Wes mentions the linkage needs a little tweaking and you'll have done
decisions to make as to how much of the fording vent tubing and fittings to
I stall. Do you have the M38 crossover pipe and air cleaner?
Forgot to mention, my WO is a downdraft carb and does not have the 90 degree bend in the upper cover as seen in your upper two pictures...more like the WO on bottom two.
None of the WO's have the 90 deg air horn like the YS series. However both the WO and YF637S are downdraft carbs.
Last resort, I can pick up a solex from Kaiser Willy's
Last resort is correct. The Solex offers no performance gain over the WO and is more finicky. Also the Solex is very sensitive to inlet fuel pressure.
I already rebuilt the WO, that's why I was leaning on using it instead of purchasing a new one. Only thing I need to do it find a metering rod adjustment tool to adjust the Metering rod.
Thanks...I'll give the WO a try once I get to the point of firing it up...maybe a year or so away.
Since I wasn't privvy to your private discussion with Brian I must ask what Air Horns are you referring to? The air horns that are the top carb casting that covers the bowl on both the WO and YS carbs or the stamped steel air horn on the civilian jeeps that pick up the duct from the air cleaner?
Hi Wes,
If I may. We are talking about the stamped steel civvy air horns.
When I bough my, ahem, project it came with a running L-head motor,
W-O carb and an aftermarket chrome air cleaner stuffed in where the
cowl battery box went. Connecting it all was a nasty hose and a stamped
steel civvy air horn with a huge self tapping screw right in the middle of
the top.
In searching for parts I sourced an oil bath air cleaner that came
with a decent civvy air horn, which I cleaned and painted and replaced
the one with the screw in it.
Fast forward about a year or so later. I bought a pile of stuff that was going
to a recycler. In there was another W-O carb. I found a home for it
as well as that air horn with the screw hole in it .
In the process of cleaning up the air horn the new owner discovered
it had an F script stamped in the top.
We are all good. I don't need another air horn, f stamped or not,
and am happy the new owner took the time to look and discovered the mark.
The lesson I was sending Mark was, especially since he had four
of the things, was it never hurts to look.
And now you can see why I always suggest carrying the entire thread public. Ryan and I intended to insure all the knowledge brought forth by the posts here would be shared by all members.
Your aftermarket air horn with a screw down thru the top must have been mounted on an adapter that was clamped the correct way to the WO carb inlet flanges.
Did your F marked air horn look like this GPW air horn?
