Idling speed on a 55 m38a1

gene · Post by **gene** » Thu Jul 05, 2012 1:41 pm

Would anyone have any info on idle speed for a 55 m38a1 my charging system is not, unless I am moving at a good rate and at 600 RPM
the engine is not idling well. Thanks Gene S.

Oldsalt · Post by **Oldsalt** » Thu Jul 05, 2012 4:20 pm

What kind of charging system do you have. The old style generator the jeeps came with have to rev up a bit before they charge. Not charging very much at idle is normal. If you have converted to an alternator then it should charge ok at a standard idle speed.

You will probably get better response to your question if you post it in the technical question forum rather than this one.

Post by **wesk** » Thu Jul 05, 2012 8:24 pm

Concerning charge rate the come in speed of the standard M38/M38A1 25 amp DC generator is 1000 to 1200 RPM so expect the amp meter to be -0- or less at idle.

There can be many causes for an uneven or rough idle. The best place to start is with a pencil, a sheet of paper and a copy of you operator and maintenance manual TM 9-8014 opened to page 80 and starting 5 lines up from the bottom of the page Par. d Stalling or uneven idling speed. Write down the results of each check as you go. Although not mentioned as a cause for uneven idling a few other problems that can cause it are timing incorrect, valves stickin, point gap incorrect (too tight), high engine coolant temps and leaking (vacuum) carb and intake gaskets and carb throttle shaft wear.

Some tools that will help a lot are:
Tach
Vacuum Gauge
Compression tester
Leak down tester.

gene · Post by **gene** » Fri Jul 06, 2012 10:01 am

Thanks, I will post it on the tech forum

Post by **wesk** » Fri Jul 06, 2012 10:34 am

I already moved it to the tech forum