New problem with older propane Clark forklift

[walnut_guy]

This forklift has a continental engine. It misses very badly until it has run for about 15 minutes. Then it straightens out and runs about right. I have not dove in yet, hoping someone can steer me first. The spark plugs seem to look ok, timing is right, points are right, oil is clean. I don"t know much about propane systems, but could it be fuel related?

 

[bc]

First, I'm going to guess at something like a manifold gasket leaking maybe from a loose or broken bolt. When it gets hot, it expands and seals itself.

Second, possibly a sticky valve and when it gets lubed up, it is ok. Propane is a hot and clean burning fuel but can be hard on valves.

 

[CAROGATOR]

For some strange reason, they sometimes don't run very well if low on water. Not always, but some of them.

 

[Vern113]

I would do a compression test while cold and then when hot. Also pull the spark plug wires one at a time when cold and determine which cylinder is bad, it could still be a spark plug or plug wire that is bad.

 

[Kruse]

The coolant runs through the propane regulator/vaporizer to keep it from freezing.

 

[ScottP]

Make sure you are using an ashless oil. The ash will build up on top of the valves and make them sticky. Delo 400 is a good ashless oil. You also need to allow the engine to warm up before putting it under a load to make sure the vaporizer is working right.
Scott

 

[Kentb of SWMO]

Your vaporizer is freezing up. Look to see if there is frost on the vaporizer when the engine is missing. If there is freezing is the problem. You need to warm the engine up before you use it.

Kent