4020 LPG will not start

[Rapidrob]

4020 was running in 30 degree F weather three days ago.
Winter storm came in and it is in the single digits now.
Tractor will not start now.
What I have confirmed :
Fully charged battery- spins engine over fast.
Hydraulic by-pass valve opened,no drag on starter.
1/2 tank of propane
Blue spark at spark plugs.
Either / Or liquid & Vapor valves did not make a diff on starting
Plenty of air.
Is the propane regulator bad?
Propane feed line and carb are frosted over when trying to start.
Engine has always started instantly on first turn over.
Should I heat up the carb?
No block heater.
Please help.

 

[matthies]

I would rebuild the regulator, especially if you don't know when it was done last. Does it start to frost over when the key is turned on? If so that would tell me that the regulator is leaking, no gas should come from the regulator until cranking. You said plenty of air, you have air filter or did you you take the oil bath cup off and check for ice? Be careful when tightening the regulator back on the tractor, as the cast mounting likes to crack.

 

[jd318]

is that got oil bath or paper filter for an air cleaner?

 

[chuck from neb]

Make sure there's plenty of antifreeze they will not run if it's a little bit low

 

[Tx Jim]

I think engine will not operate on liquid propane until engine coolant reaches near operating temp. Attempt to start/operate on vapor only until coolant is at operating temp..

If oil bath air cleaner is oil at full level in cup?

Has fuel filter(AF1399R) been changed lately?

Is electric fuel control solenoid receiving 12 volts when ign switch in in run position?

 

[Rapidrob]

Thank you for the answers.
I do not know if the regulator has ever been rebuilt. The tractor was given to me a few years back after sitting in a field for 25 years.
I did not know there was a fuel filter in the unit. I'll check that out.
The 12 volt solenoid valve is working and clicks when ignition is turned on.
I do just hear and smell propane when I turn the gas on going to the engine. I think the regulator is leaking to the carb.

 

[Tx Jim]

Fuel filter is item 12 in photo

 

[Rapidrob]

Thank you for the image. I just read I can pull out the drain plug and blow it out with the liquid valve to clear any clogs. I doubt there are as the engine was running smoothly when shut down.

 

[Rapidrob]

I found the problem. How and why has me completely baffled.
As I Stated, the tractor RAN for over an hour now four days ago. Parked and shut down,then no start.
Today I pulled the air cleaner off. I found four inches of white air filled semi-solid frozen goo in the tray!
I live in a desert at 7,000 feet ASL. Rain and snow is rare here. 18% humidity is a wet day here.
My air intake pipe is capped off with a oil filled Flax 180 degree bend filter where there is no way rain can get into the air pipe.
How moisture got in is beyond me? All pipes and hoses are in great condition with no cracks.
I only found one issue. In the center flange of the oil bath bottom cup, there is a dime sized hole in it. This will allow some oil into the center flange from the outer portion filled with oil.
Is this a problem?

 

[Rapidrob]

photo.

 

[Rapidrob]

https://imgur.com/d81XHyv

 

[J.Wondergem]

Here it is.

 

[Tx Jim]

I'm thinking engine oil was intended to cover bowl bottom both outside & inside inner circle therefore larger hole isn't the problem. I have no idea how moisture got into air cleaner assembly other than condensation.

 

[coonie minnie]

I agree, the whole cup gets filled with oil.

 

[Tx Jim]

(quoted from post at 07:10:58 01/05/22) I agree, the whole cup gets filled with oil.

We must be correct because it states to fill inner & outer bowls in 4020 operators manual.

 

[Rapidrob]

Thank you Jim for the info on the bowel.
I took the hood off of the tractor yesterday looking for a source of the water in the bowel.
After thinking of what I had done to try to start the engine for a couple of days, the Goo may not have been just water in the bowel. Retracing the steps I had done to get the engine to fire I had on several occasions pushed the center button on the regulator to make sure I had propane going to the carb. I could hear the propane bubble up in the bowel. I wonder if I had inadvertently blown propane through the oil and frozen it with propane gas? It was 8 degrees F in the morning of the snow storm.
The Goo was a bear to thaw out with an electric paint melter, and when it was finely warmed up enough to be removed from the bowel, it stayed as a very thick paste, under which was a small amount of liquid water/ ice.
I was unable to photograph the goo as it was quite a mess as it had expanded up and into the stainless steel mesh of the large air filter above the bowel.I really had my hands full.
A lesson learned to be sure. You can bet the oil bath bowel will be checked from now on.

 

[fdt860]

If you have the precleaner, it is very common to have water runs down from the nut that holds the cover, also common to have them overtoqued, creating a recess and water trap
To prevent this, an old o ring can be used and air cleaner cover needs to be kept tight.

 

[Rapidrob]

I will have to make a cover which is a good idea.

 

[steve in ok]

This is a very common problem. My 3020lp got a bucket over the precleaner any time it sat outside. It does not have to freeze to prevent starting, too much water raises the level and shuts off airflow.

 

[Rapidrob]

Oil floats on water so that makes sense.

 

[Rapidrob]

I walked out a put a plastic bucket over it.