M37 ETW1 carb main jet size

[Sigcon]

I'm in the process of rebuilding my ETW1 carb. Here's a picture the main jet -- as you can see, the threads are heavily damaged. I'll bet this isn't the first time you have seen that.

In the carburetor body, the threads are stripped as well, going all the way down as far as the jet goes. Below that, there are good threads remaining in the caburetor body, but they appear smaller in diameter than the diameter of my main jet. This leads me to think that my main jet installed in my carb may not be the correct equipment. The main jet is not included in the carb rebuild kit.

QUESTION 1: Does this look like the correct jet for an ETW1 carburetor? The major diameter of the threads on the jet is 0.440 in., and the jet hole size is #53.

QUESTION 2: Is #53 the correct jet size for an M37?


(this is my first post -- hope the image comes out readable)

Thanks for your help.

 

[EMD567]

Have you tried the G741 forum? I have gotten lots of help there also.

 

[GUNNY 155]

If the threads are gone I would look for a serviceable replacement carb or rebuildable core. They pop up on e bay all the time. Mid West Military has kits that come with all new jets and hardware as well as gaskets.

 

[Sigcon]

Here are the sizes

Thank you, John, for pointing me to the G741 forum. Didn't find quite what I was looking for, but stumbled upon much other useful information. Terrific site.

Gunny, I did go to MidWest for a carb rebuild kit which included a good main jet. The thread size on these jets is 1/4 dia. x 28 tpi (not .440 as stated in my first post). I was able to sucessfully clean up the threads in the carburetor, then I replaced the fiber washer under the main jet with gasket compound, and the new jet seated with 1-1/2 good turns holding it in place.

The hole on the replacement jet from the kit I used is also size #53, although the hole on the jet from a different kit appears one size smaller. The manual hints that different sizes may be available. I live at 2500 ft., where the air is just starting to thin. Does anybody think I might benefit from a different-sized jet?