Is this normal?

My M38A1 dosent get drove much so when i go to start it i have to prime it. The accelerater pump dosent pump much fuel. I have owned several jeeps but i dont remember how they were and gas has changed. Last year it had a problem with going slow it would serge. I got it out this year and it acted up to the point wear it wouldnt run right unless it was under a pull. Then when i got home it wouldnt ideal.I have the caburetor off soaking in cleaner. The funny part is every time i messed with it it would run ok for a short time.I thought it maybe not geting fuel to the carb but it runs up hills under a load ok.

 

Not sure if it will help but, I believe they make accelerator pumps/diaphrams out of some other material now, for some applications. Neoprene maybe (?) rahter than rubber. It has been discussed here. Maybe a search will turn up something.

 

If you have the military Carter YS type carb, the pump works differently than the civilian YF type.

My memory is from 25 years ago, the last time I took mine apart.... IIRC it is not a direct mechanical linkage, but spring and vacuum controlled, or something like that, so you won't see it directly squirt unless the engine is running...

That would explain the priming thing. I have to crank mine a long time if it has been idle for a season, since the accelerator pump doesn't assist the choke. (Again, IIRC.... )

But yes, a bad diapraghm can cause trouble. A pinhole in it messes things up. I patched one up one time by sandwiching in a second diaphragm, taken from a chainsaw carb.

 

The diapraghm is good. I have about 4 rigs that dont get started all the time and i had thought about some way to prime them. This jeep is the worst of them all.

 

"M37's have a lever on the fuel pump for priming, I would assume M38A1 has it too, is that correct PeteL?"

Yes, on M38A1 you can build fuel pressure with the hand lever on the fuel pump, before cranking. (If it still has the military fuel/vacuum pump.)
http://s34.photobucket.com/user/GBostwick/media/Fuel_Pump.jpg.html

But I don't think it gets fuel beyond the carb float chamber being filled.

 

Unless by priming he means extra fuel into the intake manifold. Or a shot of ether.

 

This is what i have to do. It dosent have a military pump. The pump is about a year old as are the fuel lines but it acts like it is loseing its prime.

 

I will look to see what it has.I dont know how long it has sat and been hard to start but it started ok after it sat a week this time.I use the chepest gas.

 

If your going to store anything that runs on gasoline for more than 6 months, try to get some aviation gas from a local airport. That stuff is good for a couple years without going bad, and eating up all the rubber parts. Of course, its not legal to run on the road with aviation fuel, but its too expensive to run the stuff on the road anyway. The lowest octane (cheapest) is fine.
-Donny

 

My local airport will not let Avgas out of their gate, and they are very touchy about it. I believe it is illegal to use due to lead content.

My experience is that older vehicles are nowhere near as sensitive to "old" fuel as newer cars and equipment. And a little Seafoam once in a while seems to go a long way to prevent issues. My jeeps routinely sit idle for the entire winter, but start easily.

 

I have had good luck with stabil in my lawn mowers. The Jeep wasnt runing right so i cleaned the carb a while back and i started it yesterday after it had sat for 6 days and it started right up like it had been runing. It has been raining alot so it may not be started for awhile. I dont have a garage at my house in town and i dont have a top for it so it parked at the farm inside. If i could keep it in town i would drive it more often.