propane troubleshooting...

patman · May 2, 2016

My issue is probably something simple...

New to my jeep, but not a new setup. Propane gets through lock-off, and the vaporizer has condensation on it after many attempted starts. When I first turned the propane on at the tank with the key on, I could hear/see/smell some propane come out (of the top maybe?) of the mixer. The first time I ever tried to start it, it fired right up and kept going at a very low speed while it was floored. (This is the 425, but was on a 22re hence idle being way down, and maybe the flow adjusted out of whack?)

Fast forward two weeks... Idle was cranked down when I got it, so I open it up. Couldn't get anywhere, so I go eat dinner and put the battery on the charger. Come back, it sputters over then dies. Now nothing. I did have it running momentarily two weeks ago, and my engine isn't in horrible shape. What's the hold up? Battery on charger again, but it was strong enough to start it on gas....

so far, I:
Bumped timing up a hair
Adjusted idle for more gas
Haven't messed with plugs. They are relatively new with 15-20 miles on them and stock gap

bbone · May 2, 2016

Check plugs wires cap and distributor.

ROKTOY829 · May 2, 2016

Re:

Is the condensation freezing on the mixer? If so it could have a air pocket or be low of coolant

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paradisepwoffrd · May 3, 2016

Re:

Have u tried pushing the button on top of the converter? If so, did it purge propane into the mixer? Are you hearing the lock off click open ?

Nuts · May 3, 2016

Have you tried a different tank? I 've had the O rings block the line before and not run. If that's not it check for vacuum leaks. If the motor can't pull the propane in it can't run.

altfuel1991 · May 3, 2016

From what you have described the engine is flooding out. You said that when you opened the valve on the tank you heard a hissing sound at the mixer. That should not happen. There should be no fuel flowing if the engine is not running. It takes vacuum from the engine to open the vaporizer and allow fuel to flow. The vaporizer probably needs to be rebuilt. When the system is right the engine should spin just 3-4 rounds and fire up with a smooth idle. You noted the system was not new so we no not know what issues the previous owner was having. The power adjustment may be off as well since it was on a 22R engine. That mixer is way too big for that engine under normal circumstances.

As far as the timing, you have to remember that propane is totally different from gasoline in the way it burns. It is higher octane but does not burn slower like high octane gas. Here are the general guidelines for setting the timing for any engine on propane.

On most applications, the timing should be a total of 30 degrees(base and centrifugal) with all of it in by 2500 rpm. What we normally do is disconnect the vacuum advance, run the engine up to 2500 rpm, set the timing at 30, lock it down, then let it idle with the vacuum advance disconnected. See what your base timing is running. If it is low,4-10 degrees for example, you can alter the centrifugal to lower that number and increase the base, still keeping a total of 30 degrees. As you increase the base timing check to see if the engine spins and starts smoothly when hot. If you reach a point that the engine bucks or loads the starter, back off about 3-4 degrees and that is your base timing. Subtract that number from 30 degrees and that will be the advance you need to have. This will provide a good start, strong idle and proper advance curve. We have had some engines run as much as 20 degrees base timing but 14-16 degrees is normal. The vacuum advance should be connected to ported vacuum and have no more than 10 degrees. This helps fuel economy at light throttle positions.

Give me a call if you need more help figuring it out.
Buddy- Precision Sales & Service
205-591-2266

__________________

patman · May 3, 2016

I didn't hear anything happen when I hit the button on the vaporizer. I'll disassemble the vaporizer tonight and take a look. Flooding sounds like it may be the issue since it only wanted to start after it sat for a while.

If the flow isn't right, is there a baseline or a general rule of thumb I can set it by without hearing the motor run, i.e. "2 turns out" or something like that?

Thanks for the help everyone!

altfuel1991 · May 3, 2016

The mixer power setting should be about halfway out. You will need to take the air/gas valve out of the housing and look down in the middle of that cone shaped piece to see where the adjustment is at. The idle setting will need to be adjusted to where ever it idles the best. Make sure the timing is adjusted first, then adjust the idle mixture and last adjust the idle speed at the throttle body.

You can bench test the vaporizer by applying air to the inlet and watching to see if any escapes out of the outlet. There is a test port on the vaporizer also where you can put a pressure gauge(0-5 lbs) and test for proper pressure. If it has over two pounds pressure it will flood the engine. Operating range is 1-1/2 to 2 lbs pressure and there should be nothing coming out of it with pressure on the inlet unless you depress the primer button.

patman · May 3, 2016

altfuel1991 said:
The mixer power setting should be about halfway out. You will need to take the air/gas valve out of the housing and look down in the middle of that cone shaped piece to see where the adjustment is at. The idle setting will need to be adjusted to where ever it idles the best. Make sure the timing is adjusted first, then adjust the idle mixture and last adjust the idle speed at the throttle body.

You can bench test the vaporizer by applying air to the inlet and watching to see if any escapes out of the outlet. There is a test port on the vaporizer also where you can put a pressure gauge(0-5 lbs) and test for proper pressure. If it has over two pounds pressure it will flood the engine. Operating range is 1-1/2 to 2 lbs pressure and there should be nothing coming out of it with pressure on the inlet unless you depress the primer button.

thanks buddy. I'm guessing the metal cylinder barely showing is what you're referring to that needs to be about halfway into where I can see it?

Also, this stingray looking thing with the brass plate... The plate was facing down with springs pressing against the black part (backside). It looks like the brass should face up with the springs being held in place by the dimples?

The orange flapper was very dirty, by the way. Still dissecting the rest of it

altfuel1991 · May 4, 2016

patman said:
thanks buddy. I'm guessing the metal cylinder barely showing is what you're referring to that needs to be about halfway into where I can see it?

Also, this stingray looking thing with the brass plate... The plate was facing down with springs pressing against the black part (backside). It looks like the brass should face up with the springs being held in place by the dimples?

The orange flapper was very dirty, by the way. Still dissecting the rest of it

It looks like the mixer is about 90% closed off. Someone must have adjusted it that way to compensate for the vaporizer blowing fuel through it. You are correct about the regulator springs, they should be facing up and fit in the dimples in the cover that holds the diaphragm in place. When you split the rest of the vaporizer apart there is a flat sponge in the vaporizer chamber that helps to capture impurities. When it gets old it will deteriorate and come apart causing blockage internally. Also check the primary seat for wear on the small rubber pad that seals against the port. When that pad gets old it can break off a chunk and cause propane to constantly flow through. You may need a rebuild kit to get it working properly again.

patman · May 4, 2016

altfuel1991 said:
It looks like the mixer is about 90% closed off. Someone must have adjusted it that way to compensate for the vaporizer blowing fuel through it. You are correct about the regulator springs, they should be facing up and fit in the dimples in the cover that holds the diaphragm in place. When you split the rest of the vaporizer apart there is a flat sponge in the vaporizer chamber that helps to capture impurities. When it gets old it will deteriorate and come apart causing blockage internally. Also check the primary seat for wear on the small rubber pad that seals against the port. When that pad gets old it can break off a chunk and cause propane to constantly flow through. You may need a rebuild kit to get it working properly again.

Buddy, you're awesome.
Inside of everything was pretty clean, and the rubber valve is still pliable, just had some gunk on it. I'll finish cleaning it all up and bench test as you described.

Thanks everyone for the help!

patman · May 4, 2016

altfuel1991 said:
From what you have described the engine is flooding out. You said that when you opened the valve on the tank you heard a hissing sound at the mixer. That should not happen. There should be no fuel flowing if the engine is not running. It takes vacuum from the engine to open the vaporizer and allow fuel to flow. The vaporizer probably needs to be rebuilt. When the system is right the engine should spin just 3-4 rounds and fire up with a smooth idle.

Give me a call if you need more help figuring it out.
Buddy- Precision Sales & Service
205-591-2266

__________________

Couldn't find a way to bench test that little amount of air. I cleaned up everything, did some adjustments to the flow and put it back together, and now the mixer started fluttering with gas coming out when I turned the key. As predicted, I'm going to need to rebuild.

Can you PM me what rebuild kits you have available? I checked out your website but couldn't find anything. I found some on eBay, but I'd like to support our vendors here if possible...

Pumpkin · May 4, 2016

Re:

Don't forget to set the valve in the vaporizer. It will dump fuel out of the mixer the second you turn the bottle on.

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peanut · May 5, 2016

and dont spray break clean on any of them diaphrams

patman · May 5, 2016

Re:

Pumpkin said:
Don't forget to set the valve in the vaporizer. It will dump fuel out of the mixer the second you turn the bottle on.

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I'm not sure I know what you mean? The lock-off? Nothing leaked when the bottle was on and the key off, only when the key was turned on

altfuel1991 · May 5, 2016

Before you spring for a rebuild kit, check the lever height under the secondary diaphragm. That is the yellow one. The lever height should be set by placing a straight edge across the housing and measuring to the pin height. The measurement should be
approximately 1/32" below the level of the body casting. That doesn't seem like much but small adjustments make big differences with propane. Also you can test the pressure on the rig by putting a low pressure gauge in the test port and using the propane to pressurize it. I will send a pm shortly.

patman · May 5, 2016

altfuel1991 said:
Before you spring for a rebuild kit, check the lever height under the secondary diaphragm. That is the yellow one. The lever height should be set by placing a straight edge across the housing and measuring to the pin height. The measurement should be
approximately 1/32" below the level of the body casting. That doesn't seem like much but small adjustments make big differences with propane. Also you can test the pressure on the rig by putting a low pressure gauge in the test port and using the propane to pressurize it. I will send a pm shortly.

The big lever that attaches to the stingray looking thing? I'll look tonight, but I don't remember seeing a way to adjust it?

Pumpkin · May 5, 2016

Re: Re:

patman said:
I'm not sure I know what you mean? The lock-off? Nothing leaked when the bottle was on and the key off, only when the key was turned on

I take it you have an electronic lockout? The vaporizer should not let any propane through it till you have a little vacuum from the motor. I learned this the hard way after rebuilding mine. Thankfully Buddy walked me through what I had done wrong.

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altfuel1991 · May 5, 2016

patman said:
The big lever that attaches to the stingray looking thing? I'll look tonight, but I don't remember seeing a way to adjust it?

You have to manually bend it to the proper clearance.

patman · May 5, 2016

altfuel1991 said:
The lever height should be set by placing a straight edge across the housing and measuring to the pin height. The measurement should be approximately 1/32" below the level of the body casting. That doesn't seem like much but small adjustments make big differences with propane.

photo bucket broke, so no pics

That pin was 1/16 above the edge. LPG is still coming out with just the key on though. I repositioned the end of the lever with the rubber pad since it didn't seem to sit flush, but neither seemed to help since I still had a leak (smaller than before!) while the key was on. I removed the top again and turned the key on, and I can see that the gas is pushing that whole arm up. Not sure how heavy the spring is supposed to be, but is it possible the gas pressure is too high? Is that little silver metal thing near the inlet supposed to seal up or reduce pressure?

Edit: I wedged another spring under the arm. Still leaked, but slower. I went and pushed down on the orange flapper and it took quite a bit of pressure to seal it off. Not from leaks/cracks/holes, but to overcome actual pressure. I removed my other spring and slowly let off, but it still had quite a bit of force that the stock green spring would not be able to seal.

So... should I be running some sort of regulator? I have the AFC 121 lock off, and the nut on top was barely tight. This looks like it can be turned down quite a bit. What does it do? Google was surprisingly not helpful