lp gas

Any LP guys out there? I have 3 LP tractors and within the last 6 months am having trouble getting them to run. The fuel in my tank is about 6 years old. Does it go bad for tractor fuel? The ac d-19 got hard to start last spring and had to have the choke out part way to run good. The mm g-706 that only gets run occasionally to keep it running loaded up while idling and now won't even try to run. The mm g-1000 that I used as a wagon puller this last fall loaded up recently on start up and hasn't run well since. Now it will only try to start.The research says LP doesn't get stale but I am wondering. Any ideas???? Thanks

I've never had trouble with LP fuel as it's in a sealed tank. What I have had trouble with is the regulator/vaporizer, usually with the vapor valve or diaphragm...

I don't have any LP tractors, but I have used LP gas that was more than twenty fives years old. I couldn't tell any difference from new.

I agree with diesel tech , regulators and valves and other parts out of the tank would be what I looked at, don't forget firing.

thank you for replys

Check the lock out and the vaporizer. Most likely one of them is your problem.

I went through a LP gas conversion school and one thing that stuck with me was that LP has a much higher ignition temp than gasoline, so your ignition system has to be up to snuff.

Have 5 of them.

LP gas on it's own has a almost indefinite shelf life. There is a precipitate that can wreak havoc though. About the consistency of gun grease and stinks to high heaven. If the tractor is fueled from a dip tube as opposed to pulling off the dead bottom of the tank you should be ok. Only times I ran into it was working on a customers tractor that he had filled from the dead bottom and a old truck body we use for our grain dryer.

Like any other carburator make sure all the lines for the convertor and carb are clear. If fuel is flowing with the engine off (you can hear it through the intake) you have a problem with the convertor. Course like others have said have your ignition up to snuff, make sure you are getting flow to the carb. Also make sure your valves are adjusted and in good shape.

jt

Did you have your tank refilled? Pretty rare, but you could have got a bad load of propane bottoms. One would expect a fuel problem if all three got sick, the fuel is the common denominator. And trying different fuel may not help if the vaporizers are gunked up.

Sir,
If you have three different units with low fuel feed problems; I would instantly look at the fuel.

I would first check the feed pressure at the carb. Low pressure means a plugged filter, or someone has butane in the tanks. Pull the filter and see how much of that black goo and rust has plugged up the bronze fuel filter. If you do not have another filter; brake cleaner solvent usually dissolves the goo. It seems funny that three units all develop the same problems simultaneously.

If the engines are acting up in cooler weather, you may have a tank mix with butane content. Propane boils at -43 degrees and butane boils at 34 degrees Fahrenheit. I once had a new boss, from Mississippi, order a truckload of butane for one of our bulk tanks. Everything was really going well, until fall came along. Every machine on site was running well in warm weather because butane has two more hydrogen atoms and one more carbon atom than propane. Old tired engines run like the devil as long as butane is warm. When it gets cold; the fuel can not boil enough to even get up into the vaporizer. Even the electric solenoid units would barely idle with the "choke button" constantly depressed. I discovered the problem when I put a pressure gauge on the main feed line. A bucket of hot water over a fuel tank brought everything back to life. We ordered a bulk tank of propane and put the tanks of butane aside for indoor equipment.

A lot of southerners call all vapor fuel butane as a habit. We frost people call everything propane. I must make an effort to remember to not call butane or pentane "propane". Here is a quick way to check for propane. The tank pressure should follow the following guide.
-44Degrees F Propane is 0 psi
0 Degrees F Propane is 28 psi
32 Degrees F Propane is 59 psi
72 Degrees F Propane is 128 psi
100 Degrees F Propane is 196 psi

Best of luck.
Charlie

thanks to all for help. had the d-19 since 1978 and never had any fuel problems. mm's not had very long. rick