Carburetor

whydahdvr · Post by **whydahdvr** » Thu Sep 04, 2008 10:06 am

I know that there are a lot of various posts about fuel, engine adjustments, and carb work but wanted to see if I could get a compilation of that.
My 1952 M38 has some carb questions/issues. My mechanic has the idle set all the way up and the float set level but thinks that the lines may not be routed correctly (the idle setting). It is running from the high idle setting but doesn't change when the setting is changed.
So, is the carb settings and set up clearly outlined in the manuals? If so, where? How should it be set up correctly? I got a carb rebuild kit from AJP, INC and my mechanic is familiar with carburetors, just not as much with the Jeep carbs.
Any advice? I know that Wes is a master of these and all-knowing about M38s so I defer to your advice.
Also, another question - unrelated - as I'm trying to determine if my M38 tub is original or a repro. Should originals all have the Jeep logo on the front of the tool box on the passenger side? Rich Saylor advised me on that but it still seems like all Willys or Jeep logos would have been removed from the vehicle design for the military. Do the hat channels need the wood stiffeners and should they be replaced at some point?
Thanks!
-Josh

Post by **Ryan_Miller** » Thu Sep 04, 2008 9:08 pm

Josh,

The basic stuff from the YS carb manual is on this site in the down loads sections at the link below.

That should get you started.

As far as can be determined, it seems all M38's produced at Willys Overland had the script logo. Ford produced Canadian M38's may be another story

http://www.willysmjeeps.com/v2/modules. ... oad&cid=43

whydahdvr · Post by **whydahdvr** » Fri Sep 05, 2008 5:20 am

Thanks Ryan!

Post by **wesk** » Fri Sep 05, 2008 7:40 pm

The only two external adjustments on the YS series carbs are the idle speed and the idle mixture. The most accurate way to set it up is to first connect a tachometer and vacuum gage. then turn the idle mixture screw full in and then back out 1 1/2 turns. Now start the engine and have your assistant hold the gas pedal so the RPM stays right around 600. Adjust the idle for the best vacuum reading you can achieve. Now have your assistant release the pedal and you then adjust the idle speed screw to maintain about 600. check your mixture setting one more time.

There are only two lines to connect to the YS series carbs. The supply line from the pump and the vent line to the air crossover tube.