I have a clark fork lift that sometime works fine and other times not. When you sometime try lifting the main ram it is very jerky and you have to race the engine for it to lift even with no load. Once it is up it doeas not hold. Other times when you start it it will lift the load with no trouble and hold it. It varys from time to time. PLease any suggestions.

go to Clark fork lift service shop and ask for a parts break down for that engine combination
The pressure plate should be the standard plate to fit that flywheel but the clutch plate may have a bigger hub section for the transmission input shaft. Either way they will be able to advise of the clutch kit part number

Don't worry I'm sure you will get the solution of your problem, just check the link I attached CLARK FORKLIFT NPR 17 NPR 20 SERVICE REPAIR MANUAL

clark forklifts have a safety device on the brake pedal hydraulics that prevents movement when lifting the forks
check the operation of that safety device as it may be jammed in the neutral position

too much oil will cause froth of the oil and that will expand out of the breather
it will cause excessive heat in the transmission oil

Frequently Asked Questions about Products Manufactured and Sold by the Clark Material Handling Company

Where can I get operator's manuals, parts and service literature, and parts for my Clark lift truck or other Clark Material Handling Company product?


Operator's manuals, parts and service literature, and genuine Clark service parts for your Clark lift truck are available from your Clark dealer. Please be prepared to provide the complete Clark serial number to your Clark dealer when ordering service literature and parts.

How can I locate my nearest Clark dealer?


For the Clark dealer nearest you, please go to our web site at
http://www.clarkmhc.com
and click on "The Dealers," and then click "Look-up Dealer " Then enter your zip code and hit "Find DLR." The Clark dealer servicing
your area will be displayed.

How old is my Clark lift truck or other Clark Material Handling Company product?


Date of shipment information is available by sending an e-mail request to [email protected]. Please provide the complete serial number of the Clark lift truck or other Clark Material Handling Company product.

Where can I find the Clark serial number on my Clark lift truck or other Clark Material Handling Company product?

The Clark serial number is stamped into the serial number plate, which is usually located in the operator's compartment. If the serial number plate is missing or illegible, you can find the serial number stamped into the frame. On a Clark lift truck, this will usually be beneath the step into the operator's compartment and may be either on the left or right side of the lift truck. Note:Rubbing the flat side of a piece of school chalk over the stamping may make the serial number more legible.

Can I still get an operator's, parts, or service manual for my old Clark lift truck or other Clark Material Handling Company product?


Photo copies of Clark operator's, parts, and service manuals are
available for many old Clark lift trucks and other Clark Material Handling Company products. Please send an e-mail request to
[email protected] for manual numbers and availability. Please provide the complete Clark serial number. Please know, however, that all Clark operator's, parts, and service manuals must be ordered from your Clark dealer

If you need further help, I’m available over the phone at https://www.6ya.com/expert/chad_70dccdc9090b1a75

I havent done of these for many a year but their is or was only a few wires for a forklift when i used to repair them ,both diesel and gas types so what exactly is the problem here that you need help with the wiring ?

It sounds like the ignition switch is bad or the wire to the run terminal on the switch is broke.

The ignition switch is hot on both the Start and Run terminals. Sounds like the Run side is dead.

check the fuseable links arround the starter
somtimes they seperate when they over heat and the ruber contracts when they cool down
if they are cooked they will pull apart fairly easily when hot

Other hydraulic functions work so it won't be a lack of pressure - likely to be a control issue though not necessarily a lack of supply through the valve.
If the tilt ram is a single double-action type of ram one side must be exhausted in order to move when pressure is applied to the other end.
If the oil can't be exhausted from the lazy end it won't matter how much pressure is applied to the other end.