Need help with Propane fuel on Tale forklift

[Phil P]

Hello All

My experience is in Gas and Diesel engines mostly much larger than this forklift.

The forklift model is
Yale
M/N G82C-030-HFT-071
S/N P-208510

This is my personal fork lift.

This unit uses Propane fuel it has the Cobra regulator and I am unable to identify the carburetor.

It will start and keep running at well above idle rpm but will not start at idle. I have to choke the air inlet to get it to start with the throttle open. This unit has always been a no start with the throttle open but always did start at idle.

It ran OK a month ago.

Any idea as to what the problem is?

Phil P

[C3H8]

Propane has to be treated just like a gas engine in identifying a problem. Do not assume the propane is the problem at first. The carb on there is an IMPCO CA500M-. The dash is followed by a 1, 2, 3, or 4 depending on the intake hose size. I don't see any signs of a filter on the electric lockoff. There is also a vacuum hose running from the carb to somewhere under the Cobra. The whole system looks pretty old and corroded but that is only on the outside. This is where you need to start.

If you haven't done so already do a complete tune up. New plugs, wires, distributor cap and rotor and if it has points replace them and set them to the proper spec. While the plugs are out do a compression test.

If that doesn't fix the issue now we can check the propane equipment. Start here.
1. Check the 12 volt power to the electric lock off when the engine is cranking. If the system is installed properly with the correct safety devices there will be no power when you just turn the key on. Power to the lock off will be supplied through a vacuum switch. The engine will have to be turning over the activate the switch and send power to the lock off. If there is a fuel filter in line between the tank and lock off it needs to be checked.
2. Inspect the hose going from the Cobra to the carb/mixer. It looks very close to the block and maybe there is a hole worn in it. Remove the hose from the carb and check the interior. While the hose if off cycle the lock off with a jumper wire. No propane should come out of the hose. If propane comes out the primary seat in the Cobra is shot. If no gas comes out momentarily depress the primer button on the cobra if it has one. Propane vapour should come out of the hose right away. let go of the button and it should stop immediately.
3. Take the carb/mixer off and clean it. That particular carb has a small plastic piston between the throttle body and mixer that can get very dirty and it can get stuck. It has an affect on the idle.
4. Lastly the cobra or CA500 may need rebuilding. Personally, I would just replace both based on the corrosion I see. Labour and time rebuilding usually add up to the same cost as just replacing with new. Screws on the Cobra will probably break if you try to rebuild it. The CA500 mixers are more throw away then rebuildable. CA500 mixers tend to wear internally as they have a piston and ring setup inside that wears the body. Neither part is really expensive. Total cost of both is in the $200 to $250 Canadian neighbourhood. You don't say where you are so I can't recommend a supplier. In Canada Proquip Sales Inc. in Calgary carries both items usually.

[Phil P]

Thank you C3H8

Sorry for the late reply this is my personal forklift I use in my garage so when I have consulting to do it stands idle.

You have answered my questions and ask one I was hoping someone here would be able to answered and that is what is that little hose from the carburetor to somewhere under the Cobra.

I had replaced the Cobra several years ago and the unit has run well ever sense.

I understand the ignition system low voltage problem and when it won’t start that is what I check first. I don’t get ignition when the battery is marginal.

I would agree with you about the carburetor the way it started the last time it ran without choking the carburetor with my hand it started at idle and ran for a minute or so then shut down. Makes me thing something happened in the carburetor.

It will start and run at around 1800 to 2000 RPM if I choke the carburetor by hand.

I will let you know how I make out.

Thanks again

Phil P

[C3H8]

I can't be sure, however, on closer inspection that vacuum hose could be going to a primer. I see it is plugged into the throttle body but I can't see the other end. If it is plugged onto a solenoid at the end under the cobra it may be a primer to add additional fuel during cranking.

The second option is it may be attached to a vacuum switch that operates the lockoff. Code requires that propane lockoffs shut off if the engine stalls. A vacuum switch was commonly used for this purpose. Post a picture of where the hose goes to and I can confirm it's function.

[C3H8]

I had another look at the pictures. I'm pretty sure that's a primer. I see a red wire that appears to go to the same location. I expect that red wire goes back to a push button switch on the dash or to the starter solenoid to operate the primer. Pushing the button if it exists will add a little fuel during cranking to hasten starting. Holding the button too long can also cause the engine to flood though. Trial and error to get the correct amount of prime.

[Phil P]

Hi

You have hit the vacuum line on the head. The solenoid it goes to only has power when the engine is cranking. When the switch is in the run position there is no power to that solenoid.

This is a CA55 carburetor I now have the parts manual for it and the regulator.

I have opened the carburetor and found that piston not to be stuck. I use a piece of stainless steel .020 wire and made sure the port was open.

The second solenoid on top the Cobra is on when the switch is in the run position. That is the fuel supply from the tank.

I am now leaning toward the Cobra being the problem. I can still run it above idle if I choke it with my hand while holding the throttle open. I can bring the rpm down to about 1200 without any problem and the engine respond to the throttle without hesitation or any indication there is a fuel problem other than at idle.

Thanks for your help

Phil P
Okeechobee, Florida

[Phil P]

Hi

Went with your recommendation and purchased a new Cobra and carburetor total cost $280.00.

Thanks for your help.

Phil P

[Phil P]

Hi

The Propane regulator and carburetor came a few weeks ago.

However I had removed the alternator that hasn’t worked for years and took it to a re-builder.

His first comment on seeing the old alternator was “What are you bringing that antique in here for I don’t have any parts for that”.

So he rounded up some parts and built me a Delco alternator that was a little larger in diameter. It fit very well except for having to change the water connection for the heating water for the Propane regulator.

Now I am in the process of putting new regulator and Carburetor on the fork lift.

I removed the item in the picture that I thought was just a long pipe coupling. I did not keep track of its orientation and it looks like to be a check valve or temperature regulator of some sort. As it stand it flows water or air in either direction. There was a label on it at some time in the past but is long gone.

My question is what is it and how will I tell which way it is to be installed. It was on the inlet side of the water flow thru the regulator.

My question is can anyone tell me what it is and how to determine which way it should be installed?
.

.
Phil P

[C3H8]

That's a thermostat to control the temperature of the coolant in the regulator. It should maintain a consistent temperature of 135F to 150F. It is installed on the exit side of the water chamber passing through the regulator. That being said, unless your forklift is being operated hours at a time it is really not needed. It's purpose was to prevent heavy ends from dropping out of the propane as it was vapourized. These oily substances collect in the regulator. The critical temperature for this to happen is at temperatures above 180F. A simpler solution is to just install a 160F thermostat in the engine. There were two or three manufacturers of these devices. At least one was a gimmick that did not function correctly and caused more problems then solutions. Yours looks like one of the better ones. The reason it is working both ways right now is because it is cold. It begins to restrict water flow as it gets hot. It works in reverse of an engine thermostat. I repeat. I would bother reinstalling it if the forklift is only used for short periods. Also I expect it might not be working due to age. You could test it by dropping it in hot water and seeing if it closes.

[C3H8]

I should of also mentioned. There should be an arrow engraved on it showing the flow direction.

[Phil P]

Hello C3H8

I took your advice and installed a new regulator and carburetor.

The unit starts and runs very well.

There are no markings of any kind on that part. There is a spot cleaner than the rest of it that looks like there was a stick on label on it.

I guessed at the orientation by the threads one end were cleaner for a longer area than the other so I put it back using the fitting that also had threads cleaned for a longer distance.

I am not sure what thermostat is installed in this unit. The unit is at least 40 years old.

The next time I run it I will use my laser thermometer to see just what temps I am running.

Thanks again for all of your help.

Phil P