M38 Carburetor Issues

RonD2 · Post by **RonD2** » Fri Nov 06, 2020 9:35 pm

Hi Johnny,
I believe that depending on your local weather conditions (temperature, humidity, dew point) that day, some condensation on the carburetor (usually around the base) is normal, especially for short runs or until the engine fully warms up to operating temp. Then it should disappear.

You said condensation around the choke? The choke butterfly is at the top of the carburetor (YS-637) in the horn. The throttle butterfly is in the base of the carb.

You should make sure that the heat riser butterfly inside the intake-exhaust manifold is operating correctly according to the manual. Malfunctioning or hooked up backwards can cause problems. Better to not have one (in warm climates) than to have one malfunctioning. Plenty of good info on it if you search this forum. And nobody can explain it better than Wes.

As far as I understand things, the good news is that so long as you have some condensation you don't need to worry about vapor lock!

Good luck!

RonD2 · Post by **RonD2** » Fri Nov 06, 2020 10:04 pm

Hey Johnny,
My apologies! I just noticed on your original post that you have a Solex carb.

Foreign to me......but seems to me the choke butterfly must still be at the top of the carb and the throttle butterfly at the base?

Pretty sure the Solex takes a very different fuel pump set-up than a stock M38 ---- different fuel pressure and volume requirements.......

Good luck!

redrad · Post by **redrad** » Sat Nov 07, 2020 10:47 am

Hey Ron, thanks for weighing in on my posts.

I have gotten a lot of good info from this website, and learned a lot about MV Jeep’s. Since my Jeep has been altered not all OEM applies. Ex. Now converted to 12 volt, Solex Carburetor, aftermarket fuel pump, also I believe the serial number incorrect only 4 digits, no timing marks on pulley or engine serial number above water pump. All that being said I love my Jeep and will strive to make it motor pool reliable.

Thanks

4x4M38 · Post by **4x4M38** » Sun Nov 08, 2020 7:54 am

Hi Johnny,
Where did you find your serial number?

redrad · Post by **redrad** » Sun Nov 08, 2020 10:38 am

Passenger side fender well, and on the dash plate as well. The dash plate had no contract number or delivery date, leading me to believe it was a reproduction.

redrad · Post by **redrad** » Sun Nov 08, 2020 12:36 pm

Post by **wesk** » Sun Nov 08, 2020 9:46 pm

Definately not correct.

redrad · Post by **redrad** » Sun Nov 22, 2020 7:59 pm

Jeep now running great, new Solex, plug wires, and choke cable, timing set by ear by Bob at 820 Jeep in Ft Worth.

Thanks for all the ideas and suggestions guys.

CapnDan · Post by **CapnDan** » Fri Nov 27, 2020 10:24 am

Good to hear Redrad. I finished putting the fuel tank back in my M38A1, verified no leaks in fuel lines by a combination of pressurizing and pulling vacuum on fuel lines. Now have new in tank fuel filter, with new pick up line, new in-line filter on inlet side of fuel pump and on inlet side of Holley pressure regulator which is in line going to carb. I primed fuel lines to fuel pump using a marine tank primer bulb on inlet side of fuel pump. Removed primer bulb and connected fuel line to pump. I then verified fuel flow thru fuel filter ahead of pressure regulator by cranking engine over for 20 seconds, it pumped 6 ounces. This is the no-name glass bowl fuel pump that never fills up the bowl. So doing the math I get 8.43 gallons per hour. I had driven it around my 86 acres in low gear, pulls good without stalling. Fuel filter in line to carb is full of fuel. Took it for a short highway run on Thanksgiving and runs good up to 50 mph!
Happy Thanksgiving!

4x4M38 · Post by **4x4M38** » Sat Nov 28, 2020 1:39 pm

Danny,
It is normal for the glass bowl to not be full.