Forklift Troubles

Hey everybody, this is my first post on PM. It pertains to a 1960's vintage clark forklift, model C60, 6000 # lift. The story leads back to machine tools which I'm sure I will be having questions on at a later time.

Story on forklift: Growing up, my dad sold seed corn and beans for Pioneer. He had this green forklift and an even older utilitruck clark (the more art deco lift). I never remember the other one running, it always just sat in the back corner and we would jump on it as kids and pretend like we were lifting heavy stuff. Dad stopped selling for Pioneer in the early part of the 2000's to focus on farming and this forklift got parked at the farm which it sat until a few months ago when I drug it into town. I am trying to get into some welding and machining as a hobby/business and this forklift will be nice to move stuff around, and it is my dad's so it is free in a way.

What I have done. This forklift was always the reliable horse around the shop. It is a LPG model and the smell of it brings back memories when I was a kid. When I got it into town I noticed the key was missing so I went to napa and bought another switch to replace the keyless one. I also bought new points and a condenser and also a new oil and air filter. I set the points to .015-.020. I can't remember off the top of my head. It is getting plenty of spark so I think I set them right. I put a battery in the lift and when I tried to start it, it fired and then just turns over, it won't fire more than once right at the beginning of when I turn the key. That is all it will do. The first time I worked on it, the coil was leaking oil, so I put a different coil on it but I still can't get it to pop off. Does anyone have any ideas? The thing I am curious on is the little fuel safety device. The hose from the tank goes into a fitting that's got wires coming off of it and I think it is a lockout device or some safety apparatus. Does this need to be wired to the switch? The only thing I wired onto the switch was the starter, the battery, and the ignition. There was a myriad of other wires on the old switch, but they all powered gauges and meters that are no longer functional...or so I thought. Would that device let a quick surge of gas in, and then cut it off? The vaporizer has a little push button primer but you can push and push it and nothing happens. Any tricks to try, or am I forgetting something? Thanks in advance for your help.
Andy

Andy,
Welcome to the site. The little solenoid is the fuel shut off and it needs to open when the key is turned to START/RUN. You can test this by toggling the key and holding a hand on the solenoid..you should feel it click. The solenoid may be wired off the key side of the coil too. If the solenoid is not opening then any device down stream won't be getting fuel and the machine will not run.

Stuart

If it is setting for a while between firing it is probably leaking enough to fire up but not enough to run. If it still won't fire with power applied bypass it for a test.

atomarc said:

Welcome to the site. The little solenoid is the fuel shut off and it needs to open when the key is turned to START/RUN. You can test this by toggling the key and holding a hand on the solenoid..you should feel it click. The solenoid may be wired off the key side of the coil too. If the solenoid is not opening then any device down stream won't be getting fuel and the machine will not run.

Click to expand...

I have seen a problem where the engine would start to fire and then stop, and it was the solenoid that is connected somehow with the propane unit. I don't have LPG anymore, my current lift is diesel, but the propane converts need to be cleaned regularly also, they have some diaphragms that can be replaced on most models. That stuff gets gummed up and it causes problems as the LPG is cold. Seems they even run it through the engine block to warm it, on the one I had (Mitsubishi engine in a Caterpillar).

So many things could be the OP's problem, one really needs to just eliminate them one by one. Speaking from experience, calling someone that knows LPG could save you a LOT of time and grief in the long run...the time they will save you in troubleshooting it yourself could be plenty. OTOH, fixing it yourself is golden.

Andy,

I think your problem is the new key switch. There has to be some method to supply the points with power when you are in START as well as RUN. Sometimes this is a relay switch inside the starter solenoid and other times it's the construction of the key switch itself. The easiest thing for you to do is either beg, borrow or steal a 12 volt tester. These have a grounded pitgtail on a wire and a handle with a VERY sharp ice-pick point with a lamp inside the handle. When the pigtail is grounded and the probe is touched to a live point the little lamp inside illuminates and you know you have power. Using this tool you can verify that the key side of the coil has power on START and on RUN. You can also check the fuel solenoid the same way...it should have power whenever the key is switched from OFF.

You can make your own tester using a 12 volt lamp some little wire and some soldering time. I don't think you have a big problem...just a little hiccup. Do some sleuthing and the old beast will be running in no time.

Check the battery polarity on the old girl..typically negative ground but sometimes on old stuff you'll find a positive ground system. The wire from key to coil should go to terminal marked + when a negative ground, to - when positive ground.

Stuart

Hi Andy!
" think your problem is the new key switch. There has to be some method to supply the points with power when you are in START as well as RUN. " I bought a old Clark forklift last week(owner put new key switch in from napa auto) and this is what went wrong..... Stuart.....great call Dean

Thanks

Thanks guys for all of the help. I bought a volt tester after school today before reading all of these posts and I am going to work on the ol girl tomorrow morning and see where I get to. I will fill everyone in tomorrow evening. Thanks again.
Andy

Try to locate a wiring diagram so you can verify everything is correct.

These things are stupid simple until stupid wire in wrong place makes you look in wrong place too.

A quick 'hotwire' from batt pos. to coil pos. will eliminate some questions about switch.

I checked the forklift over and the LP shut off was wired correctly and upon further finding it is not functional I took it apart and it was just filled with gunk and corrosion. I ordered a new one from Clark and I am hoping that will fix my problem. I unhooked the hose coming from the shut off to the vaporizer and there is no LP coming out so that leads me to believe the shut off isn't functioning correctly. I will check in the next couple of days and let everybody know. thanks again for the help

Andy,

Good detective work. Often there is a small filter mounted near the LPG tank that pre-filters the gas before it gets into the sensitive metering apparatus. It has a round cloth filter pad which can get plugged up. Maybe this is part of the problem..or maybe your rig doesn't have one!

Stuart

atomarc said:

Andy,

Good detective work. Often there is a small filter mounted near the LPG tank that pre-filters the gas before it gets into the sensitive metering apparatus. It has a round cloth filter pad which can get plugged up. Maybe this is part of the problem..or maybe your rig doesn't have one!

Stuart

Click to expand...

Stuart,

This is a common problem, but you also mentioned the solenoid above, and I wouldn't rule that out either. The solenoid gets gummed up also, and the pin can't be retracted, as you point out above and they causes the problem also. If the banjo/converter is gummed up bad, that would cause it, but the solenoid is something to check also.

The propane banjo/converter and the solenoid are the 2 most common problems with propane giving the results mentioned in the OP. Make sure the solenoid is clean also, and operating properly. That pin needs to pull out of the fuel line or nothing is going to get any fuel.

Cheers,
Alan (doesn't have LPG anymore)

Okay everybody, I'm still need help on the old forklift. I replaced the electronic fuel shut off and that is definitely working. The old one was not letting gas to the mixer or vaporizer. Now when I turn the gas on it will just leak and leak, it is coming out of the air cleaner. Now I am wondering if the shut off is constantly on or what? The key can be off and if I turn the gas on it will just leak out the air cleaner. Does anyone know what else I could try? I feel like I get one thing figured out and another thing is wrong.

Update** I think I may have an issue with the switch that I bought from Napa. If the key is off there still power going to the shut off. My question is if gas is allowed to get through the shut off shouldn't it stop when it gets somewhere like the carburetor? Thinking about a gasoline powered engine there is a float in the carburetor that will stop the flow into the engine. If the float is messed up it will allow gas to get into the engine and Flood. Does the carburetor have a float similar for LP gas as well? I'm beginning to wonder if I don't have carburetion issues as well

Andy,

The carburetor on a LP rig is actually refereed to as a 'mixer' as its only chore is to mix fuel with incoming air...it has no float. The converter has a needle and seat attached to a large diaphragm that responds to engine vacuum. These are typically gunked up after years of sitting, just like your solenoid was. It's possible the converter has a hole in a diaphragm too. The only component that could leak fuel when the solenoid is opened is the converter, not the carburetor.

Stuart

Stuart, thank you for the help. So you think the problem is with my vaporizer? Some people call that a mixer, just clarifying. I plan on rebuilding the vaporizer, I would like to wait til I get a rebuild kit so I know what to take apart and replace. So if the fuel is leaking out of the air cleaner, you think their is a problem with the vaporizer? There is a carburetor on the engine but their is nothing to leak on that? Thanks again to everybody for their help.

I have had some experience with Propane powered forklifts. For a while it was my responsibility to keep 4 of them running. Quite trouble free until our Purchasing Agent decided it would be a good idea to switch Propane suppliers. All the full and empty tanks were stored outside on our loading dock. When the tank on a lift truck ran out, the operator would take the empty tank off and go get a full tank, put it on, and get back to work. One day, one of the trucks would barely run. I checked everything I could think of and all seemed to be OK. Finally, I just started taking the fuel system apart. I found brown goo everywhere. Nothing was broken, but lots of goo had made a mess of the entire fuel system. I spent most of that day cleaning the goo out of everything and putting it all back together. The machine worked perfectly. It took many weeks and lots of down time for the forklifts before I finally traced the problem to the "new" supplier of our Propane. He had not sold any of his Propane to anyone else to be used in an automotive type application. He claimed he had never heard of that problem before. We switched back to the original supplier.

We had used Propane fueled lift trucks for many years without a problem. I must conclude that the brown goo is not just something that all Propane users have to live with. If your Propane has brown goo in it, find another supplier.

Whenever you are finished using your fork lift, shut the Propane off at the tank. More than half of the Propane powered lift trucks I have worked with had fuel systems that leaked........most leaked very little. How much is required to make a really big boom? I have no idea......never wanted to find out.

Good luck

Roger

ajk2004 said:

Stuart, thank you for the help. So you think the problem is with my vaporizer? Some people call that a mixer, just clarifying. I plan on rebuilding the vaporizer, I would like to wait til I get a rebuild kit so I know what to take apart and replace. So if the fuel is leaking out of the air cleaner, you think their is a problem with the vaporizer? There is a carburetor on the engine but their is nothing to leak on that? Thanks again to everybody for their help.

Click to expand...

I bought a couple rebuild kits off of ebay They are easy to rebuild.

John

ajk2004 said:

Stuart, thank you for the help. So you think the problem is with my vaporizer? Some people call that a mixer, just clarifying. I plan on rebuilding the vaporizer, I would like to wait til I get a rebuild kit so I know what to take apart and replace. So if the fuel is leaking out of the air cleaner, you think their is a problem with the vaporizer? There is a carburetor on the engine but their is nothing to leak on that? Thanks again to everybody for their help.

Click to expand...

Yes, I think the problem is the vaporizer. It has the equivalent of a needle and seat and when the engine is off a spring pushes the seat closed so no fuel makes it to the carburetor. The carburetor only mixes the fuel with air to the correct proportions, it has no ability to shut off the fuel supply. If you open the solenoid valve with the engine off the fuel should go no farther than the closed needle and seat in the vaporizer..it should never get to the carburetor until the engine actually cranks over to create vacuum on the diaphragm in the vaporizer.

Stuart

One quick thing I just realized. This may be a really dumb question but does the coolant system need to be full to allow the vaporizer to function properly? I just realized that there isn't coolant in the machine. It was drained when it was parked. I ordered a new rebuild kit from a clark dealer close to here. A new kit will definitely not hurt anything, just wondering about the coolant level. Thanks.
Andy