Clark C-20:
1973 C20 B running problems LP

My lift sat for 2 months. Since then it hasn't run rite or at all. Ive replaced plugs,wires, distributor cap. "Point and plugs gapped" Replaced regulator, and solenoid. Took off and cleaned carb. Just recently I finally got it running but its rough. I gotta play with the idle screw and gas pedal. It wont idle or run for long. Now this is my first forklift and propane as a fuel. My questions are, what could be wrong? Is there a governor to adjust? Timing cant be off rite? It ran great till it sat. Do these models have a fuel filter? What other adjustments can be done other then the idle air screw on the carb? Bought this machine to build my garage and it hasn't run since day one.
  • Posted 19 Sep 2023 09:15
  • Discussion started by Nick_Mencucci
  • Rhode Island, United States
Nicholas mencucci
Showing items 1 - 7 of 7 results.
I finally got her running! After replacing the spark plugs and wires i figured let me replace the distributor parts. And thats what fixed it. Runs amazing now. Makes sense after the fact. The plugs were fouled up from dumping fuel and not having a good spark. Took me 2 months to figure that out. Literally the last part i was going to buy before i gave up. $30 bucks. Lol thanks for the help. Hope this helps people in the future.
  • Posted 28 Sep 2023 13:46
  • Reply by Nick_Mencucci
  • Rhode Island, United States
Nicholas mencucci
If you smell LP and you can get it to run at all, turn off the LP at the tank while it's running. If it eventually smooths out and runs fine for a short while before running out of fuel, you know you're getting too much fuel from the regulator. If you've got a Model J or K regulator, I'd replace it with a Cobra.

If you're planning on keeping the truck I'd replace the distributor with an electronic one. Maybe that's just me though. I adjusted so many C500 points back in the day that I still sometimes dream about doing the job. The complete distributor went for $100-150 when I last looked. (years back)
  • Posted 26 Sep 2023 04:35
  • Reply by lumberjack
  • Maryland, United States
After trying to start for a min or two I do start to smell propane. Is there a way to adjust the fuel? Over the weekend i took off all the lines, regulator ect. I removed the fuel solenoid as well. All parts were completely fine. Reinstalled all lines, and pressure tested everything. I replaced spark plugs with new ones. All gapped to.025. Still will not run rite... kinda worse then before. I cant get it to idle. Im going to buy a new points set for the distributor. Is there any way to check if a distributor is working rite? Other then taking out plugs and looking for spark? I did notice that 2 plugs were dirty. 1 was clean and had a blue color on the steel. The last plug was clean but no discoloration. I also did a pressure test on the engine and all 4 cylinders were over 100psi. So its not a bad head gasket.
  • Posted 26 Sep 2023 00:13
  • Reply by Nick_Mencucci
  • Rhode Island, United States
Nicholas mencucci
I'm sure it's not recommended but I crack the inlet hose to the regulator just very briefly and look for a small squirt of liquid LPG. If that's ok I test the primary pressure, the 1/8 brass pipe plug on the front of the regulator. If I remember right you're looking for 1 to 3 psi. Automotive vacuum gauges often have a pressure side that will read that low. I'm surprised you found a regulator with a button. All the replacements I've seen for the last decade have been the Cobra model. (which is recommended)

Also make sure all your vacuum lines are connected. Another thing, running too rich will give you the same symptoms, only difference is you'll probably smell the LP. I wouldn't mess with the distributor because it runs well on sprayed fuel.
  • Posted 24 Sep 2023 08:49
  • Reply by lumberjack
  • Maryland, United States
Thanks fornthe reply. So the Tank is half full, I filled it myself a couple months ago. Fuel filter was clean. I even tried to start without it in and no difference. So propane is good. The carb or "final regulator" was a little dirty. But not horrible. There was a plastic diaphragm that looked fine, wasn't stuck open or shut. I replaced the two gaskets when I reinstalled. But didn't help at all. Im going to take off the regulator again. Its brand new but idk im out of options. Take a look it and see if clogged or something. Ive taken the hose that feeds the carb and pressed the primer button and it sends propane out. Do you think a bad distributor could be causing this? I replaced the cap and plugs and wires. But not the distributor. I dont know how to set timing and its not a cheap part. What gets me is it run mint on a shot of starting fluid. For 5seconds lol. That is what has me stuck on it running lean..
  • Posted 24 Sep 2023 07:20
  • Modified 24 Sep 2023 07:30 by poster
  • Reply by Nick_Mencucci
  • Rhode Island, United States
Nicholas mencucci
There's a plate and diaphragm on the top of what you're calling a carb, I think Clark calls it a final regulator. A bad diaphragm here will give you problems. But also check that you're getting good LP from the tank and that there is only one black gasket at the Rego fitting. There is also usually a fuel filter at the fitting where the LP hose from the tank attaches to the back of the truck. Good luck with it.
  • Posted 24 Sep 2023 04:17
  • Reply by lumberjack
  • Maryland, United States
Update: I can get her to "run" but its for a few mins tops. Has to be full throttle and the whole time she is sputtering and choking. Sounds like she is starving for fuel. So i turned off the tank and sprayed starting fluid in the intake. Starts up and purrs like a kitten. So its a fuel problem! But I've already replaced everything except the carb. Which i cleaned and looks great. I plan to remove all the lines tonight. See if theres and obstruction. Then ill inspect the new parts. Maybe i put a line in the wrong place. Doubt it but never know. Not getting much help from here. But maybe this will help someone else in the future. Like the next guy i sell this POS too. Lol
  • Posted 21 Sep 2023 09:40
  • Reply by Nick_Mencucci
  • Rhode Island, United States
Nicholas mencucci

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

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

Upcoming in the editorial calendar
DIGITISED STOCK CONTROL AND FORKLIFTS
May 2024
PRODUCTION OF MATERIALS HANDLING EQUIPMENT IN NORTH AMERICA
Aug 2024
Oshkosh to acquire Spain’s Ausa Oshkosh, WI, United States
Upcoming industry events …
May 30-31, 2024 - Singapore, Singapore
June 11 - 13, 2024 - Rotterdam, Netherlands
October 23-25, 2024 - Ningbo, China
Fact of the week
In a room of just 23 people, there is a 50/50 chance that at least two people have the same birthday. In a room of 75 people, there's a 99.9% chance of at least two people matching.
Hangcha CBD15
China
Used - Sale
USD1,600
Toyota 7FBEU20
Flesherton, Ontario, Canada
Used - Sale

PREMIUM business

Zhejiang UN Forklift Co., Ltd
Manufacturer of IC forklifts, electric forklifts and warehouse equipment.