JLG 40HA, it runs fine on gasoline, and if the gasoline tank is empty, it runs perfectly fine on propane. But if there's any gasoline in the tank, when switching to propane, the engine runs rough, it doesn't run correctly , I'm not sure how to describe it any better. It will keep running long enough to switch back to gas. And I always do, I'm not sure if it would keep running or for how long. So that's the problem, not a big one really. Propane is much cheaper, I'd like to have the gas as backup, instead of propane. A couple of notes. I drained the gas tank, there was some pretty nasty rust in there, but the filter was clear when blowing on it. I noticed four nuts on the bottom of the tank area, sort of around the drain plug, is this how you remove the gasoline tank? Just these nuts, and the fuel line -- is that all? I installed a new fuel filter, which had a clear plastic case, so you could see in it. I had about 5 inches of fuel in the tank, but no fuel would come out the line at the filter. So of course I sucked on it, nasty business. And that made it better. So I'm guessing the fuel system is some sort of siphon, is that correct? If it is a siphon, how far off the bottom is the line inside the tank? Maybe this is designed to prevent water and gunk in the line. Is this a standard thing? Do you have to siphon it, or would it have eventually started? Another thing, this new fuel filter, has a big bubble in it. So I thought it might be a good idea to try and get that out of there. I removed the top line from this see through filter, and let it fill completely with gas. Then with my thumb on it, put the line back on, and the bubble came back. But it runs fine. So, should I get that bubble out, is this a problem? If it's a problem, how do you get that bubble out? Anyway, these are bonus questions, I'd really like to get it running good on both fuels. Thanks.
Crap, I've already asked this, I'm reviewing the older thread now. Sorry. I wouldn't mind know about the gas tank stuff though. Thanks.
I can't address the 40HA specifically, but most JLG of that vintage with the steel fuel tank did have the pick up tube going into the top of the tank, tube extended down into the tank to a few inches off bottom. Drawing fuel from tank is not so much a siphon effect, it's just the typical suction of the fuel pump that draws fuel. Don't worry about the bubble in the fuel filter, it will cause no adverse affect. Not sure of your engine, possible a Ford VSG411. If it has manual fuel pump on the side of the block then it should have an in-line electric solenoid operated fuel shut off that blocks fuel flow when you're operating on propane. If it has electric fuel pump, electric pump should be non-operating when operating on propane. Lastly, the Zenith carburetor should have an "anti-dieseling" solenoid on it. When operating on propane, this solenoid should be preventing gasoline from entering main jet of carb. The alcohol gas we use nowdays is murder on the spool of that anti-dieseling solenoid, makes the spool stick. It's very important, no, critical that you use some form of fuel additive in the gasoline to deal with the effects of the alcohol, that crap is terrible for carburetors.
Alright, I'll check the things you mentioned here. It seems reasonable to assume that it's trying to run on both gas and propane, when propane is selected. I want to check the gasoline shutoff first. I'm not sure where it is located. Today, I could see the gasoline fuel line coming across from tank. On mine there was a filter as it went vertical, up to another component, that I didn't really look at too closely. Is this probably the fuel shutoff item #51 from the diagram? How would you go about checking this, take off the top side and see if gas is coming out when propane is selected? I guess it still could be wiring, if you have flow. So I guess I could check the wire at this component. Is it normally closed and powered open or what? Thanks very much. It does have the ford engine, I think it's the vsg411. It has some sort of solid state plug wire system, it's a 1996 It didn't seem to be drawing fuel on it's own, before I did my siphon thing. But once fuel was at my clear filter, you could see it suck right on up, the first time I switched to gas. I usually start the thing on propane, it just seems to work better. Maybe I'll somehow try to check out the fuel pump. See if it's working up to par.
I checked the parts diagram for the engine, man, what a crappy diagram, which doesn't surprise me from JLG, diagram is a mess. Then looked at the electrical diagrams, from what I see it has the DIS ignition system with a manual fuel pump, fuel pump mounted on the side of the block, old school fuel pump operated by a lever on the camshaft, at least that's what it looks like to me. But electrical diagrams do show both things I described above, a fuel (gasoline) lock off valve and an anti-dieseling solenoid on the carb. That lock off valve should be in the fuel line between fuel tank and fuel pump (unless someone has removed it). The anti-dieseling solenoid is mounted to the base of the carb, round thingy with a single wire going to it, not to be confused with the choke which is another round thingy at the top of the carb.
If you do, in fact, have a fuel (gasoline) lock off valve, when you have propane selected at fuel selector switch it should have no power on the red wire going to lock off when engine is running. If someone has removed the lock off valve, with a manual fuel pump, you're going to have the problem you describe, you need to install a lock off valve if that's the case.
Alright, good stuff. I'll get on it tomorrow and report back. I may take a picture too. I print out your notes and I take them with me. It's very helpful, thank you.
I thought I'd throw up a picture while I'm waiting for the oil to drain . This is what I think is the gas shutoff, it looks like a solenoid valve to me. And you can see a red wire behind the crimp splice. I hate to take anything apart, because something usually breaks. And this must be a mechanical fuel pump. I don't see how this thing can shut off when the machine is running on propane. When running on propane, is this mechanical pump sucking a closed off line above the gas shutoff? That doesn't seem too sound of a design. It's either going to wear out the pump or the valve, or the hose. I must be missing something. Anyway, I'm going in...
Fuel shut off works, OK. It does not run on propane with gasoline in the tank I'm a little mystified now, okay, got running on gas, then pulled off the gas line, and switched to propane, and it wouldn't run right as described, so, switched back to gas, fuel line still unconnected and ran the gas out until it began to die, then switched to propane and it ran fine. So, gas shut off works, the residual gas is interfering with propane mode. Is this the dieseling valve described above? Or something in the gas carb? thanks in advance.
Here is my gas carb, is that the anti-dieseling solenoid on the lower left? What does this do? Does it open a valve or something? Do you take it off and put power on it to see if it actuates? Or how do you test it? Do you think this is causing the problem described above? edit I just google anti-dieseling valve and found your, willie, discussion with 40F guy who couldn't shut down using the E stop switch. I don't see how the anti-dieseling switch could be my problem. I think it just might be my gas carburetor is leaking or something is worn out or stuck. anyway, thanks Now that I think about it again, maybe this is it. Does the fuel selector switch activate this thing? It shuts off the main jet right? When it powered is it being held open? Remove power, and the jet is shut off, correct? I'll check this tomorrow.
I'm still latched on to this. Is this the anti-dieseling solenoid? They call this the Engine Fuel Shutoff with wire $218 yikes! For this kind of money, I think I can live with my problem.
You're making progress Stone7. I've been in Virginia today, just now checking in. So far you have identified the components involved; 1st pic is gasoline shut off solenoid valve, 2nd pic is diaphram type fuel pump, 3rd and 4th pic is anti-diesel solenoid on carb. The other part in all this is the propane shut off solenoid valve in the propane supply line as it enters the propane regulator. Here's the short story of how your system works; the anti-diesel solenoid has power whenever ignition is on, whether on propane of gasoline, because the same wire that powers solenoid goes to electric choke bi-metal spring heater coil. The choke has to open/close whether it's running on gas or propane. The fuel select switch sends power to either the gasoline shut off valve or the propane shut off valve depending on what fuel you have selected. Now, let's say you're going to use gasoline. You turn on ignition, anti-diesel solenoid and choke get power, gas shut off valve gets power. You begin cranking. Once the engine gets oil presure, the oil pressure switch on the engine makes contact and sends power to the ignition control module to provide spark and make engine run. When you turn off ignition, gas shut off solenoid closes, anti-dieseling solenoid closes, blocks flow of fuel through carb main jet, engine runs momentarily, then dies. Oil pressure goes down, oil pressure switch takes power from ignition control module after engine dies. When running on propane, pretty much the same process, it's just the gas shut off solenoid remains off preventing gas flow to carb, and propane solenoid valve opens/closes depending on ignition on/off. So...yes, if you have engine running on gasoline, you should switch the fuel select switch to the center position (now neither gas or propane solenoid has power) and allow engine to keep running. Anti-diesel solenoid is still open. Run engine until it dies. This purges gasoline that's in the carb float bowl. Once engine dies, switch to propane, start and run engine with no effect of gas in carb. Lastly, it's no harm for diaphram fuel pump when running on propane, diaphram is sucked flat because gas shut off solenoid is blocking gas flow. Cam lever continues to operate, but it does no harm to the diaphram.
Okay, so it's operator error. It's me, it's alway me dammit! Thanks very much. So there's a procedure when switching from gas to propane, I never would have guessed this! Well, anyway, I learned a little and a lot about my machine. Have a good weekend and thanks. Stay tuned for proportional control issues, I'm going to dig into that next. And I'll tell the story of the little bird that built a nest in my basket control box.