Cat GC40KS forklift won't start.

[Brian Bobb]

Hi, for couple of months we've been having some issues starting at LP forklift. We left it for a while and it managed to start a few months back and it worked until now it won't start again. What are the common issues that can cause that? We are having spark and the propane is reaching the regulator.

 

[BigWrench55]

Make sure that there isn’t a hole in the line from the regulator to the carburetor. You could be over fueling there is a 1/8” npt thread plug on the regulator. You can plum in a gauge there. Anything over 3.5 - 5 lbs is to much fuel. Another way to check for over fueling is to remove the line from the regulator to carburetor and hold it a little way back and try to start it. If you get it running that way. You are over fueling. Check the diaphragm on the mixer. Check your spark plugs to. If they are worn it won’t run. LP engines are real fickle and hard to figure out. Good luck. Ask me anything and I will try to help.

 

[Brian Bobb]

We have changed the spark plugs on it. Where is that plug located on the regulator?

 

[BigWrench55]

Not sure if this is the one that you have but most LP forklifts have this set up.

 

[Brian Bobb]

It is a different one but it does has that at the bottom. I will see to check that tomorrow.

 

[Brian Bobb]

Not sure if this is the one that you have but most LP forklifts have this set up.

So they bought a new regulator and it still won't start.

 

[BigWrench55]

Can you take a picture of the fuel system and intake. I can be more helpful if I know what you have.

 

[Brian Bobb]

Can you take a picture of the fuel system and intake. I can be more helpful if I know what you have.

 

[BigWrench55]

 

[BigWrench55]

Inside there is a diaphragm. Open it up carefully because there’s a spring inside that you don’t want to lose. Remove the diaphragm and look for holes. Also you have a 4.3 GM motor. They are notorious for getting moisture inside the distributor cap and won’t run. You can still get spark but it won’t run. Check out those and if I can think of anything else I will reply with more.

 

[Brian Bobb]

Hey, we've checked the diaphragm and the distributor cap, everything seem to be ok but it still won't start. We've tried switching the high tension leads for 1, 3 and 5 and it started to back fire. How is that possible?

 

[BigWrench55]

I’m not sure what you mean by high tension leads. But if you are back firing then your engine should run. Next would be compression test on each cylinder.

 

[Brian Bobb]

The leads that connects to the spark plugs. With them in the correct firing order, nothing happens. Switch them around, they make that back firing sound.

 

[Brian Bobb]

What is the purpose for those three wires on the distributor?

 

[BigWrench55]

That’s your ignition module. If you are getting spark then it is working. I’m willing to bet that you have a bad cap and rotor. That ignition system is real finicky and I have waisted a lot of time troubleshooting no starts when it was the cap and rotor the whole time. And yes you can still get spark with a bad cap. It’s just erratic inside and doesn’t fire good.

 

[Brian Bobb]

Thank you. Do you know the parts number for that and where I can get it?

 

[BigWrench55]

I don’t know what the part number is That is a 4.3 liter GM engine. You can get from your local auto parts store.

 

[4x4ford]

1996 and up s10 is it a 4.3 should get you the right parts

 

[Brian Bobb]

Hey, sorry about the late reply to this. You were right it was the cap that is having the issue.