M38 problem solved!

[Keith]

YaHoo!!! My M38 is finally running like it was 6 months ago after I restored the entire engine compartment and components. If you have been reading my posts I have been troubleshooting my engine for 6 weeks, trying to find the cause of my engine running rich. To make a long story short, the cause of all my headaches was something simple like I had expected but could not put my finger on.

IT WAS THE CARB (YS model)!!

But the fact that I had just rebuilt it 6 months ago (and it had been running perfect ever since), and then one day out of the blue it started running rich, AND I even checked out it out for cleanliness, etc...made me think it couldn't be the carburetor. I would have never guessed 6 months later and only MAX!! 10 gallons of gasoline through it that the DIAPHRAGMS were already BAD!!!!!

WHAT THE HECK!!!!!

I bought the kit from DeBellas jeeps parts and it was a new kit, "NOT NOS" and supposed to be compatible with today's fuels. Yet the fuel did eat at the diaphragms' material causing fuel to pass through it, allowing too much fuel into the engine.

Be Warned: the diaphragms were grey in color.

The new kit is from Midwest Military and it was a complete master kit and the diaphragms are red this time. Hopefully they will last more than 10 Gallons and 6 months this time!!!!!

Now to focus on the future: WHAT can I do to help prevent this? I live in Florida and they do advertise 10% ethanol (and who knows what else) in the fuel.

Has anyone else experienced this problem here in Florida, or anywhere else, and have any solutions?

Thanks for everyone's help and advice,
Keith

[Bill_F]

I did not have good luck with the carb I bought from debella as well. I now have one from midwest that will be going on in the spring.

[wesk]

Try to avoid the ethanol. Also a trip once in awhile to a local small airport with a couple of 5 gallon cans to load with some 100LL Avgas will help a lot by bumping the octane number up a couple and adding significant amount of old fashion lead. About 2 gallons of 100LL to each tank of 87 auto gas should help thing along. The 100LL is also the best deal for storing the jeep over the winter with gas in the system. The 100LL in aircraft stores fine fo 2 years and more with no degradation in it's chemical structure.

[dv3468]

Gentlemen: I good friend of mine who works on small engines and snowmobiles warned me about the ethanol based fuel we get today. He told me the gas is playing havoc with carborators, fuel lines and gas tanks. The problem is that ethanol absorbs water. The gas also starts to break down after a few weeks. He recommended putting sta-bul gas additive in the gas. The gas we pump into our cars is used up/replaced after a week so it doesn't have a chance to break down. He also suggested adding the sta-bul in the gas cans we use for lawnmowers, snow blowers, ie.

I also like Wes' suggestion about putting aviation fuel in our green machines. My son uses 100 octane racing fuel in his Banshee. Maybe I'll put some in my green machine and see if I can get it to go over 45 mph!!

Regards to everyone. Dennis

[wesk]

Dennis, be careful. We used to steal the really high test old purple dyed avgas 115/145 in the 60's and very early 70's on base and run it in our military trucks in the air force to burn the carbon out because we ran the trucks all day long stop and go slow flightline driving. She'll get the valves hot enough quick enough to burn them. We'd slip in about 5 gals and run the trucks down the runway or taxiway late at night at 60 or 70 MPH and watch the sparks and carbon roll out the tail pipe and then the old girls would run like a sewing machine for a few days and then back to the runway.

Staybyl is a short term band aid to a hopeless fuel compound. Long term storage will last several years with the 100LL avgas (blue dye) but Staybyl hasn't proven it self past 1.5 to 2 years.

[Keith]

Wes, does the 100LL avgas come with lead in it or should I add the lead additive to it, that you find at the local auto part store? Also you mentioned 2 gals per tank, could I just run the 100LL avgas straight to keep things simple? Reson being I never fill the tank full in an effort to keep the fuel in it as fresh as possible.

I didn't metion it in my first post but I have been adding the Sta-Bil gas additive to all my gas cans that I use for all my small engines including my M38, so that is NOT a good solution for what happened to my carb kit!! I'll continue putting the Sta-Bil in my small engines gas cans. But I wanted a different option for the M38.

Thanks guys, with out this sites help I would not have been able to do all the things necessary to get the M38 were it is today!!

Thanks again! Its finally running again just in time for the Florida MVPA show this coming weekend, hope to see some of you there.

Keith

[wesk]

The octane rating rating is a bit high for the Willys fours. The lead content is also higher than the old pre-1973 leaded 87/90 octane gas we use to have.

So no you do not need to add any lead substitute and yes you should mix the 100LL to reduce the octane numbers and dilute the lead a little.

Since the 100LL mixed gas will store 2 to 3 times better than your ethanol gas with or without stabyl you really need not be concerned about filling the tanks.

[Keith]

So 2 gallons of 100LL mixed with 3 gallons of 87 octane should be a good blend??

Thanks
Keith

[wesk]

My comments have addressed 2 gals to a tank of auto gas.

M38 tank = 13 gals so 2 100LL and 9 auto gas.

or a ratio of about .25 (100) to one (auto).

[miljeep]

There are two stations here in town that sell fuel without ethanol one is a Gulf and the other is a Shell and at about 10cents more a gallon ya cant beat it Iam in Allentown PA Scott out