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Hard to start, rough running LPG forklift

snowman

Diamond
Joined
Jul 31, 2004
Location
Southeast Michigan
Nissan LPG forklift.

Either starts really hard, or doesn't start...then idles really rough.

I've never really worked on anything LPG powered...if it was gas I would have already cleaned the carb and rebuilt it.

LPG I'm clueless.

Is the regulator/carb assembly something that can be disassembled/cleaned safely, or just rebuilt/replaced by a qualified technician with special tools?

One of the times I disconnected the LPG line, it had water in it. Either water, or something that had no petroleum smell/feel to it.

Any advice?
 
Have you changed the tank? I have had one or two that where foul.
I would not re-build the carbs. Just buy new ones>.

Good Luck
 
There are a few different types of propane systems. Most difference is how they turn on/off. All can be rebuilt. Usually they are just gummed up with goo.

Follow the propane hose and write down the model numbers of all the parts then look them up.

troubleshooting is different depending on what system you have.

My Komatsu has a Nissan engine and uses a vacuum signal to start and stop the vaporizer.
 
The carb and regulator/vaporizer are not very complicated. Actually the carb is actually more of a flow sensor that generates a vacuum signal to the regulator to modulate the pressure for proper air fuel mixture.

You never said but is the engine running rich or lean when it is idling. LPG has a particular odor with some sooty smoke when rich and not much of an odor when lean. If the mixture is rich, you might have a sticky or leaking regulator/vaporizer needle valve.

If you are running lean at idle, you might have a bad vacuum hose between the car and the regulator. This is an easy and cheap fix.

The carbs and regulators are relatively cheap, so if you need to repair the carb and/or the regulator/vaporizer a kit might not be the least cost or best approach considering your experience and that you are asking for advice here.
 
I was having hard start/ no start issues with my Daewoo lift earlier in year, problem turned out being an oil pressure switch. When cranking engine, the solenoid valve that allows propane to flow does not get electricity until oil pressure switch is activated. No idea if all lifts are wired this way.
 
I was having hard start/ no start issues with my Daewoo lift earlier in year, problem turned out being an oil pressure switch. When cranking engine, the solenoid valve that allows propane to flow does not get electricity until oil pressure switch is activated. No idea if all lifts are wired this way.

Good point. Some are wired so that the solenoid valve also opens when in start. When in ignition mode, the oil pressure switch will be in series to the solenoid valve. Bad wiring or switch will cause no start/lean start issues.
 
The propane regulator/vaporizer could be gunked up with tar. They usually have a plug that can be removed to clean it out. Do it with the engine hot so the tar is soft.
These devices use radiator coolant to warm up the liquid propane, maybe there is a leak in yours and that is where the water you saw came from?
 
I am pretty sure it's ignition related...I left the seat up on it yesterday after looking at vacuum lines. It poured a bit, and now it won't start at all. And the more I think back, the hardest days have been when it's either humid or just rained...when it's been dry, I don't get a lot of problems.

So, I'll replace the cap and rotor and see how it does.

It's been a while since I've worked on anything with carburetor / manual ignition any bigger than the lawnmower.
 








 
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