Clark forklift problem

[Kalai]

Hi, I have a 1969 clark forklift, it has a propane set up and there seems to be a problem with it.
I do not know much about propane systems, this has a filter lock, and what looks like a regulator and then what looks like a carburetor.
The filter lock is new but the rest is not, the fork lift will start with no problem but when I push down on the gas pedal it starts to stall, if I let off the gas pedal it will idle again, if I stop the engine and tap on the regulator it will start up and run with no problem and after 1 or 2 min. it will start acting the same, wanting to stall if I press the gas pedal, if I go and tap on the regulator it will work for a min or so.
Is this a regulator problem or is it a carburator problem, or is it something else. Alny help would be great, aloha.

Kalai

 

[willie59]

What I have seen in working on propane engines like these is over time the vaporizer, what you're calling a regulator, gets clogged up with a goo. I have no idea what it is, maybe something they add to propane to lubricate propane pumps, buts it makes a mess of inside of vaporizer. I have tried to rebuild vaporizers with mixed good/bad results, to the point I finally gave up on that, hard to charge a customer for a vaporizer rebuild that don't work, and instead fitted a new vaporizer. One thing you must do if you do that is get the correct vaporizer for the engine as they use different springs inside for different engine applications. Would be best to call Clark for correct unit.

As for the propane carb, if it has something like an Impco model 100, you can remove carb, disassemble, and clean with carb cleaner, then replace diaphram.

 

[Kalai]

Hi Willie59, thanks for the reply, I would have posted sooner but I have beem haveing computer problems.
I changed the vaporizer with a new one and it still does the same thing, there was no change, so would you think that it is the carb that is the problem or could it be the fuel lock, I changed the fuel lock a few months ago with a new one but I live in a very wet area and it has been very wet, let me know what you think, also if it is the carb do you know where I can get a rebuild kit, I live in a part of Hawaii that does not have all the comforts of the mainland. Thanks and aloha.

Kalai

 

[willie59]

What brand/type of propane carb does it have?

 

[Kalai]

Hi Willie59, the carb I have is a impco and it says "mod ca 50" ,there is also th letter A on it and these numbers 3846084.
Let me know if you need any more info or if there is anything else I should look at, thanks and aloha.

Kalai

 

[willie59]

CA50 and CA55 units can be problematic, and even more sensitive to crud inside carb than a model 100 Impco. Air valve must move freely, no sticking or stiffness moving down and back up. Have also seen idle cutoff piston disintegrated affecting operation. Take the air horn off top of unit and check movement of air horn with screwdriver, make sure it moves free. With engine at idle, screw idle mixture screw in until engine rpm starts to drop, then back mixture screw back out 1/2 turn. Then take engine to full governed rpm, tilt mast back until it stops and hold it there overriding relief valve for tilt back. Turn power mixture valve back and forth between R (rich) and L (lean) until engine achieves its highest rpm. And if the unit is terribly dirty inside, you should consider rebuilding or replacing it as they are not terribly expensive.


http://www.usgemini.com/Forms/50_55_series_rk_inst.pdf

 

[Kalai]

Hi Willie59, if I decide to get a new carb, would I be able to get the model 100, would that bolt on or would I need to modify it, thanks for your help, aloha.

Kalai

 

[willie59]

I would think you could convert to a model 100. Try contacting these folks for some information.

http://www.usgemini.com/index.html

 

[Kalai]

Hi Willie59, let me tell you what I have done so far, and I am still having the same problem.
I have a new fuel lock and a new vaporizer and I rebuilt the carb with a new kit I bought. I still have the same problem, it will start sometimes and run for a while, sometimes a few seconds and sometimes a few minuts, most of the time it will run for about 30 seconds and then stop, after it stops, I can start it sometimes and sometimes I can not.
I even bought a rebuild kit for my old vaporizer and I rebuilt that one and replaced the new one and I still got the same problem, could it be the carb even though I rebuilt it, is there some other problem that you think I should look at. Thanks for your help.

Kalai

 

[TD24]

LP Problem

Model number: Like C40-50B or C500-40-50. It is cut in the frame in inch high digits
on the right hand side of the frame below the floor board level typically

Why is the filter lock new?

Is it a simpe filter device(Hose from tank to it on bulkhead-Hose out of it to lock off under hood) or some other configuration?
Have you tried another tank on it?
Truck is starving for fuel -How did it run before this problem and how did it materialize
(Run good-Stumble some-Now consistent)?
.

 

[willie59]

I'm no expert on LP systems for sure Kalai, just have some experience with them. I'm just not fond of CA-50/55 carbs, I'd much rather have a 60 or 100 depending on engine size.

Do you have an LP filter on the system? If so, possible it's clogged and won't allow propane flow.

 

[Kalai]

Hi TD24 and Willie59, after thinking about what you both said and all I have tried and the set up on my fork lift, I went outside and lifted the propane tank up so it is standing upright and not laying on its side, I thought that there might be some dirt or rust that is cloging it, well it works with no problems now, I figured that if there was rust or dirt then the way the tank was it would be easy to go out th ehose and make a clog, so when I stood it up that vrified that, then I layed it back down but turned it so the valve was not facing down it is now facing up and it still wors great, just like it did before.
Thanks very much for your help and aloha from Hawaii.

Kalai