M38 Carburetor Issues

CapnDan · Post by **CapnDan** » Mon Oct 19, 2020 11:32 am

I was aware that their was a spacer in the parts list, but I know I asked Bob at 820 Jeep Parts in Fort Worth if the after market pumps he has require the spacer and he said no. If you space the pump away from the block I tend to think that would reduce the arc the pump lever travels since the cam lobe lift height is constant, therefore reducing the flow. However, without the actual mounting geometry dimensions it is hard to say for sure. How does one actually measure the flow rate of the pump? Just crank it over a specific amount of time and measure the volume? Manual says pressure should be 4.5 to 5 PSI. I have note seen anything of flow rate requirement. The glass bowl pump only makes about 3.5, maybe adequate since it seems to run okay now with just a gas can sitting in the body tank pan area , but the flow is suspect since it just seems to trickle into glass bowl. I have blown out all of the fuel lines and am awaiting new in tank filter from Midwest Military to install in my freshly cleaned tank. The tank filter is the only thing I did not replace when I first got it running again in 2007.

4x4M38 · Post by **4x4M38** » Mon Oct 19, 2020 2:28 pm

Hi Dan,
The glass bowl doesn’t stay full normally.

redrad · Post by **redrad** » Mon Oct 19, 2020 7:22 pm

I purchased a fuel pump w/ vacuum from Vintage Jeeps, they also sell one without vacuum. According to Russell they have had good luck with this fuel pump from Omix. I have not installed yet due to family illness but will update when I do. I did ask about the spacer and was told it came with the proper gasket.

Post by **wesk** » Mon Oct 19, 2020 7:59 pm

I did ask about the spacer and was told it came with the proper gasket.

Not a very informative answer. All I can say is the 50's and 60's CJ3B, CJ5 and CJ6 all use a spacer as well. So I think it is safe to say all the Willys/Kaiser L-134's and F-134's using a dual action pump use a spacer. Since the spacer has a Willys PN and is listed as a Willys factory produced part it's easy to see why new or rebuilt dual action pumps do not come with them. I suggest that if you do install this aftermarket pump and it still does not meet specs that you try ordering (from a jeep parts dealer) the spacer PN 800361 for the M38 & M38A1, or the 647669 for the CJ's.

RonD2 · Post by **RonD2** » Mon Oct 19, 2020 11:27 pm

Following with interest.......
I was going to say this post is getting kind of convoluted between redrad's (the OP) and CapnDan's issues...?...but nothing that couldn't maybe be solved by having the right tech manual or two?

Dang. Did I say that out loud?

CapnDan · Post by **CapnDan** » Wed Oct 21, 2020 5:12 pm

Where is the TM 9-1828A in the downloads?

CapnDan · Post by **CapnDan** » Wed Oct 21, 2020 5:15 pm

disregard prior question, I just fount it!

CapnDan · Post by **CapnDan** » Wed Oct 21, 2020 5:15 pm

found not fount

redrad · Post by **redrad** » Fri Oct 30, 2020 2:53 pm

Well after a long delay I replaced fuel pump like in kind same as what was on there. Jeep seems to run much better, I have noticed the base of the carburetor seems wet, the base gasket appears to be at least 5/16 thick, so not sure what I have there, the base bolts were not completely snug so I got almost a half turn more tight. If it continues to leak I will pull carb and try to match up with a new gasket.

Post by **wesk** » Fri Oct 30, 2020 10:17 pm

On the M38 that thick carb base gasket is correct.

redrad · Post by **redrad** » Sat Oct 31, 2020 6:51 am

I thought that might be what is under the carb, and good to know you have a thin gasket on each side. Do you use any type of sealant with these gaskets or just put them on dry?

Post by **wesk** » Sat Oct 31, 2020 12:52 pm

No add on sealants to be used.

redrad · Post by **redrad** » Thu Nov 05, 2020 2:41 pm

Well the gaskets and diffuser came in today. After installation the mounting bolts were too short for a full nut, lacked about three threads. The diffuser measured 1/4” thick and the base gaskets were 1/16” thick. These were. Kaiser Willys. So I tried to Google Carter 1A-65 thin gasket but did not get any hits. Any idea if there is a thinner gasket, if so who sells it.

Thanks

Post by **wesk** » Thu Nov 05, 2020 10:55 pm

Buy some composite gasket material (roll or sheets) in the needed thickness from your local autoparts store.

Here's a how to video: https://www.youtube.com/watch?v=tseqlAjD1GM

redrad · Post by **redrad** » Fri Nov 06, 2020 11:37 am

I actually had some 1/32 material on hand. Made two gaskets put It back together and drove it around the neighborhood. Got back popped hood no leaks, but did notice the carburetor was sweating around choke, doin’t know if that’s an issue because Jeep ran pretty good.