Air vent on YS 637 carb

Mjfire1949 · Post by **Mjfire1949** » Tue May 13, 2014 5:24 pm

I am looking for a picture showing the plumbing for the air vent on a YS637 carburator on my M38. I want to replace the WO that is currently installed. I know it goes to the breather, but I'm not sure where.

OKCM38CDN · Post by **OKCM38CDN** » Tue May 13, 2014 5:38 pm

If I remember correctly, the vent line goes from the Y637 vent at the top of the carb to the port on the cross over tube. The line is 13 inches long and can be made of 3/16" steel or copper tubing with inverted flare nuts on both ends...

Hope this helps...

Mjfire1949 · Post by **Mjfire1949** » Tue May 13, 2014 9:26 pm

Thanks OKC.

Post by **wesk** » Tue May 13, 2014 10:02 pm

There are many illustrations showing the vent tube's routing. Quite a few in your basic 4 volume manual set for the M38. TM 9-8012, TM 9-1804A, TM 9-1804B and ORD 9 SNL G-740. All of these manuals are available free to you on our downloads page.

My photo album (first one in our album site offers several hundred technical photos that will answer 90% of the questions that are posted here.
http://www.willysmjeeps.com/v2/modules. ... _album.php

This is Fig 4 from TM 9-1804B page9.

The tube is shown in all the following tech references as well.

TM 9-1804B Fig's 3 (Pg

, Fig 2 (Pg 6). TM 9-1804A Fig 1 (Pg 4), Fig 7 (Pg 18), Fig 15 (Pg 23), Fig 29 (Pg 36). TM 9-8012 Fig 21 (Pg 79), Fig 22 (Pg 80), Fig 23 (Pg 107), Fig 24 (Pg 108), Fig 28 (Pg 115), Fig 29 (Pg 116), Fig 34 (Pg 127), Fig 44 (Pg 152), Fig 45 (Pg 153). Finally in the Parts Manual ORD 9 SNL G-740 fig 01-1 Page 11.

Mjfire1949 · Post by **Mjfire1949** » Wed May 14, 2014 8:36 am

Many thanks Wesk. I was just approved to view the downloads yesterday. I am starting to feel my way around the site. Again, thanks. I have located the port on the crossover tube. It was blocked off, but is still useable.