Clark C500-YS60:
propane fuel system issue

Hi all, new to forum. I'm trying to resurrect an old, neglected clark lift. It starts & runs but the fuel line from the regulator to the carb ices, then thaws when engine warms up. As soon as that lines thaws, it starts running rough and eventually dies. I've determined that the diaphragm in the regulator is bad as fuel seeps through the vent hole in the cover when cold then stops when engine warms. Can anyone help me identify this regulator/fuel system. I'm attempting to find a diaphragm with little luck. Regulator is much different that Impco that I'm familiar with. I have a picture but don't see where to post in the forum??
  • Posted 9 Dec 2022 04:25
  • Discussion started by twalens
  • California, United States
todd wayne
Showing items 1 - 13 of 13 results.
take the gas pipe off the mixer and suck on it, if you cannot suck gas out of the vaporiser there is a problem with it. Does it have the VFF30 lock off or is it an electric solenoid? If its the vff30 when you suck down the vacuum pipe does it hold vacuum or can you constantly keep sucking? If you can constantly keep sucking the VFF30 is bad
  • Posted 5 Dec 2023 06:28
  • Reply by andrew_k
  • England, United Kingdom
OK guys,
Replaced the Mixer and put it back together. I tried starting it, and it ran for a brief second and quit. Now are can't get anything out of it. IDEAS?
  • Posted 5 Dec 2023 06:24
  • Reply by David_Stokes
  • Illinois, United States
David
Hi John,

Thank you for your reply.

I put a new coupler on the line. I think the one on it was the original. I thought, well, maybe the little nub on the end may be worn or the tension on the spring was not strong enough to open the valve all the way. Changing it did not do any good.

I just got a new LP Tank today. Filled it, tried it.. SAME THING!

So, I just got off the phone from ordering a new Mixer /Carb. There isn't anything else to replace.

Keep your fingers crossed!

Or send money LOL.. kidding. I hope this works.

Thank you to everyone who has provided information and help! I'll let you know if the Mixer is/was the cause.
  • Posted 29 Nov 2023 07:48
  • Reply by David_Stokes
  • Illinois, United States
David
Should I just replace it too with a NEW Carb / Mixer?

Does anyone have a part number for the C500YS60 Carb/Mixer?

Is there a big difference between the "Y" and the "YS"?
Thanks for the help!!!!!!

David
  • Posted 29 Nov 2023 07:03
  • Modified 29 Nov 2023 07:11 by poster
  • Reply by David_Stokes
  • Illinois, United States
David
I replaced the coupler with a brand-new coupler. I currently have a NEW LP tank on the way. I truly am running out of components to replace. Prior to replacing the converter and the coupler, there was no smell of gas. Now there is a faint smell of propane. I can't figure out where I am smelling from. The last thing I have to replace is the carburetor.
  • Posted 29 Nov 2023 01:02
  • Reply by David_Stokes
  • Illinois, United States
David
David,

Yes, the carb is referred to as the mixer. Though on this lift as old as it is you probably have an actual carb. They throttle shaft will wear over time allowing a vacuum leak causing a lean condition.
  • Posted 29 Nov 2023 01:01
  • Reply by Fishmech
  • Virginia, United States
The hard to do we do right away. The impossible just takes a little longer.
I replaced the LP converter with a NEW one. When you say the "Mixer" are you referring to the carburetor?
  • Posted 29 Nov 2023 00:53
  • Reply by David_Stokes
  • Illinois, United States
David
Andrew, I just sent you a pic of the convertor.
  • Posted 29 Nov 2023 00:47
  • Reply by David_Stokes
  • Illinois, United States
David
David,

I would suspect the diaphram in the mixer has failed. They will get small cracks in them that will not let the engine run at full throttle. You should be able to take of the top to inspect. Need to be very careful as you can cause additional damage and replacement is the only course. If you find a small rip or tear in the rubber, I have used RTV to seal. Must let it sit for a day to dry. Wil hold up for a short time, still needs replacing.
  • Posted 28 Nov 2023 01:10
  • Reply by Fishmech
  • Virginia, United States
The hard to do we do right away. The impossible just takes a little longer.
Look inside of the l p coupler to tank
should not be a
Seal I've gone on service calls with same
Problem and found when they changed tanks the seal from old tank stayed in coupler
Sounds crazy but with that seal in there it won't open valve enough for fuel
  • Posted 22 Nov 2023 10:34
  • Reply by John_Bradley
  • Texas, United States
Jb69
if gas is freezing you need to do radiator pressure test i suspect you have a leak in the system which airlocks the water circulation through the convertor hence the freezing if no leak you have a bad convertor
  • Posted 21 Nov 2023 18:27
  • Reply by skyreach
  • Victoria, Australia
reach for the sky
Hi, I have the same forklift and what WAS on it was an IMPCO Model K. Why, I am not sure, but this model is VERY hard to find. I replaced it with a Unisourse TSA/800115159. I purchased mine from ALTA Material Handling. 630-966-0450. $126.19

Ok, for my issue. The forklift was running fine until it ran out of fuel. Using the SAME TANK I had the tank refilled and put it back on the forklift. Opened the value and it started right up. Went to give it gas and as soon as you passed ideal, it started coughing - like it's not getting enough fuel. Turned off the tank valve and ran the forklift out of fuel again and disconnected the tank. Then reconnected the tank and just "cracked" the fuel open a little. I was thinking, well maybe the safety value engaged. It started right up, running smoothly, pushed on the gas pedal, and the same thing happened.
I nursed it out of the middle of the driveway trying to figure out what was wrong. Checked the "O-RING in the fuel tank to make sure it was still there. I spent the rest of the day on YouTube and the Internet trying to figure out the problem. I found one video that said, "PUSH THE LITTLE BUTTON ON THE SIDE OF THE VAPORIZER." That the button acted kind of like a choke. So, I did. Will shoot, I had FULL PEDAL AND IT WAS RUNNING GREAT! I released the button, and it went back to the same problem. More reach and I was convinced that somehow the vaporizer had gone bad. So, I replaced it with the one I mentioned above.
Surely, this would fix the problem - RIGHT? Nope, Started the forklift and I have the same problem. Ok, it's an old forklift so I thought, MAYBE the connector to the tank has worn out enough that it is not making good enough contact with the fuel tank to release enough gas when there is a demand. I ordered a new Connector, and O-Rings for the fuel tank. Put them on today, and the problem still exists.
THERE JUST ISN'T THAT MUCH TO A LP SYSTEM TO GO WRONG!
Last summer I put all new points, condenser, cap, rotor, plugs, and wires. Basic tune-up stuff. I checked the cap and rotor to see if they were still in good condition and they are. Again, all this started AFTER I RAN OUT OF FUEL AND PUT A REFILED TANK BACK ONTO IT!
The last thing in the line of possible components is the carburetor. So I am looking for a rebuild kit for that now.

Can anyone tell me what is going on?
I do have a video of the forklift running at idle and when I am trying to give it gas.

Thank you.

P.S Andrew, if I can figure out how to post a pic of the model K and the one I put on I will.
  • Posted 21 Nov 2023 05:54
  • Reply by David_Stokes
  • Illinois, United States
David
Email the pic
  • Posted 9 Dec 2022 06:39
  • Reply by andrew_k
  • England, United Kingdom

Post your Reply

Forkliftaction.com accepts no responsibility for forum content and requires forum participants to adhere to the rules. Click here for more information.

Having trouble using the Discussion Forums? Contact us for help.

Movers & Shakers
Michael Oren Michael Oren
Senior Vice President of Sales for the Americas, Dematic
Director of Membership, Lifting Equipment Engineers Association (LEEA)
Chief Operating Officer, Vecna Robotics
Executive Vice President, Port Solutions, Konecranes
Global Industry News
edition #1187 - 11 July 2024
This week’s news is electric! Continue reading
Toyota 8FGCU25
Flesherton, Ontario, Canada
Used - Sale
Terberg YT223-4X2
Balling, Denmark
Used - Sale
Upcoming industry events …
September 4, 2024 - Blair Athol, South Australia, Australia
October 9-10, 2024 - Houston, United States
October 21-22, 2024 - Riyadh, Saudi Arabia
Fact of the week
As it turned out, Tom Cruise divorced all three ex-wives when they turned 33 and each wife is 11 years younger than the previous one.
Toyota 4FD240
Yokohama, Japan
Used - Sale
Toplift Ferrari TFC36-48
Stoney Creek, Ontario, Canada
Used - Sale
USD1

PREMIUM business

Cascade Corporation (World HQ)
Leading manufacturers of attachments, forks and related technologies for forklifts and AGVs.
Fact of the week
As it turned out, Tom Cruise divorced all three ex-wives when they turned 33 and each wife is 11 years younger than the previous one.