Need help with propane system

[Charles Sauder]

Currently have an 87' yota p/u with a 22r that was converted to propane before I bought it. Has been doing just fine for 2+ years. Was on the trail one day and it starts sputtering and acts like its out of propane. Ok fine, I go to the back to switch the tanks and realize the tank I am switching from is still at least 2/3 full, and the first 1.5 feet of line coming from the tank is frozen up. Anyway I switch to the full tank and get back to the shop. I figured there must be a leak so I tighten everything up. Go ride again in a few days, same issue. I then change the entire propane line from mixer to tank, and all fittings. Went to harlan last weekend, was able to take the tanks to about the same level, maybe 2/3 full. Did a lot of tank changing over the weekend. The line would still be frozen over for about a foot from the tank when the truck would stall. Here's the kicker: I was able to run one, and only one tank completely empty. Have about 6 other tanks I've never had issues with before that all now only run down to 2/3 full before acting like they are empty. Anyone have any idea what else could be going on? Did 6 of my tanks coincidentally shit the bed at the same time? I'm lost, wth?

 

[Scottal]

Are the O rings in the tank hookup still good? Mine would begin to freeze over in cold weather when the tank was almost empty. But there's no reason for it to do that when the tanks are that full. Only other thing I can think of is tank pickup tube. Steel tanks have a shorter pickup tube than aluminum if you are dealing with steel tanks. Propane also doesnt run as long in the winter as it does the summer due to temperature effect on the pressurized tank. Tanks been dropped hard recently or something weird could have broke the pickup tubes off for some reason.

 

[Charles Sauder]

Are the O rings in the tank hookup still good? Mine would begin to freeze over in cold weather when the tank was almost empty. But there's no reason for it to do that when the tanks are that full. Only other thing I can think of is tank pickup tube. Steel tanks have a shorter pickup tube than aluminum if you are dealing with steel tanks. Propane also doesnt run as long in the winter as it does the summer due to temperature effect on the pressurized tank. Tanks been dropped hard recently or something weird could have broke the pickup tubes off for some reason.

Thanks for the reply. I didn't even realize tanks had a pick up tube. I did just replace the tank hookup fitting with a new one, I am *assuming* it is sealing and o rings are good. I am also dealing with only aluminum tanks, too old to throw those steel ones around these days, ha ha. I used to notice a little propane left in them last winter when it got cold, but this is A LOT. I wonder if it is something with the pickup tubes in the tanks, as the one tank, I was able to run completely empty. That was also my newest tank.

 

[Scottal]

Thanks for the reply. I didn't even realize tanks had a pick up tube. I did just replace the tank hookup fitting with a new one, I am *assuming* it is sealing and o rings are good. I am also dealing with only aluminum tanks, too old to throw those steel ones around these days, ha ha. I used to notice a little propane left in them last winter when it got cold, but this is A LOT. I wonder if it is something with the pickup tubes in the tanks, as the one tank, I was able to run completely empty. That was also my newest tank.

Its still worth checking on those O rings. There should be two in the tank valve. How are your tanks mounted? Did you try moving them a different direction when this happened. I realize you prolly dont have enough hose for this cause mine didnt either but its worth a shot. If your tanks are standing up, trying laying them down and see if it is same problem. Or if laying down, stand them up.

 

[Brud720]

line and tank freezing happens when the draw is to great for volume of tank, high pressure to low pressure effect. Have you tried to run both tanks through a manifold so both tanks to draw at the same time? I've seen the liner on the flexible hoses fail and collapse causing a restriction. If all this fails try turning the tank on end valve down and see if it changes the 2/3 tank outcome.

 

[Charles Sauder]

Its still worth checking on those O rings. There should be two in the tank valve. How are your tanks mounted? Did you try moving them a different direction when this happened. I realize you prolly dont have enough hose for this cause mine didnt either but its worth a shot. If your tanks are standing up, trying laying them down and see if it is same problem. Or if laying down, stand them up.

I will check. No I haven't tried moving them in a different direction yet. They are laying down, but have been that way, and worked well for 2 years, which is why I hadn't tried yet. But I will.

 

[Charles Sauder]

line and tank freezing happens when the draw is to great for volume of tank, high pressure to low pressure effect. Have you tried to run both tanks through a manifold so both tanks to draw at the same time? I've seen the liner on the flexible hoses fail and collapse causing a restriction. If all this fails try turning the tank on end valve down and see if it changes the 2/3 tank outcome

I will try that and see what the outcome is. Could it be a possible internal vaporizer/ regulation problem causing it to draw more propane than usual? Hence the freezing. Not even sure how the mixer regulates propane intake. Never messed with it.

 

[paradisePWoffrd]

I will try that and see what the outcome is. Could it be a possible internal vaporizer/ regulation problem causing it to draw more propane than usual? Hence the freezing. Not even sure how the mixer regulates propane intake. Never messed with it.

There are typically 3 parts to the system; the lockoff valve, regulator/vaporizer, and mixer/carb. The lockoff is typically either electric or vacuum, and is basically a fuel shutoff. The regulator converts liquid propane to vapor. It typically uses the heat from the engine coolant to keep from freezing up. It generally uses a vacuum reference to determine the amount of flow to provide to the mixer. The mixer has a diaphragm in it, that draws in vapor as the engine vacuum pulls it open. There are mixture screws on them to adjust the idle mixture, and on some, the high flow mixture.

As said, when something in the system freezes, it is typically from the liquid to vapor conversion. Either there is a leak or the flow is too high for some reason and the fuel is vaporizing.