M38A1 flat spot on acceleration

hurtlocker · Post by **hurtlocker** » Sun Sep 04, 2011 9:51 am

Hi
I finally got my M38A1 restoration finished. Everything working except when trying to accelerate, there is a definite 'flat spot'. I also get this if I blip the accelerator when trying to rev the engine from idle. The jeep starts on the button and idles great. Once over the flat spot, the jeep has loads of power and runs ok. During the restoration I fitted a carb rebuild kit so I have no 'before' comparison to make, only the 'after' which is where I am now. Any ideas will be most welcome.
Martin

donthedickens · Post by **donthedickens** » Mon Sep 05, 2011 7:47 am

Look at the trouble shooting guide here. Look under hesitation.
Some times the idle is set too fast.

http://www.thecarburetorshop.com/Troubleshooting.htm

Post by **wesk** » Mon Sep 05, 2011 11:22 am

First two things to check when the accelerator pump does nit seem to squirt is the diaphragm and the position of the spring.

If the kit was an old pre 80's surplus kit the diaphragms won't holed up to today's gas.

If you followed the original drawing in the TM 9-1826A Carter Carb manual you have the diaphragm spring on the wrong side of the diaphragm.

These are simple things to check and do not require dismounting the carb. Simply remove the four diaphragm housing screws and inspect.

The correct layout is illustrated below: