This article is all about forklift propane fuel system troubleshooting.
So if your propane forklift won’t start, you’re in the right place.
You'll learn the most common fuel system problems that can cause a no-start situation.
And you'll get a step-by-step guide to fixing them.
Let's dive in!
WARNING: Forklift Repair Can Be Dangerous Work. Always Put Safety First.
Only trained, qualified, and authorized individuals should perform maintenance on propane fuel systems.
Propane can be as cold as -44° F and will cause serious injury if it comes in contact with your skin.
Additionally, propane can leak from the fuel system and accumulate on the floor, presenting a fire or explosion hazard.
Always put safety first and call a professional before attempting to do any work yourself.
That said, if you’re not a trained technician, we’ll list the actions you can safely perform in the “Action Items” list after each section.
There’s a lot of confusion about how exactly a forklift propane fuel system works.
Let’s get on the same page by going through just that.
The Propane Fuel Tank
First off, it all starts with the propane fuel tank.
Liquid propane boils and turns into a vapor at -44° F.
So to keep it in liquid form, it needs to be cooled or compressed.
And that’s exactly what happens in the propane tank.
Additionally, the propane tank acts as a fuel pump.
The pressure inside the tank forces the fuel through the fuel line and into the next stop: The regulator.
The Regulator
From the tank, liquid propane flows into the forklift's fuel regulator, first reaching the fuel filter.
There, it’s stripped of any contaminants.
After that, the fuel goes into the regulator.
But it can’t just be allowed to flow freely - it needs a “gatekeeper.”
And that’s the job of the fuel solenoid.
The fuel solenoid is opened only when the key is turned in the ignition and the starter is engaged.
At that point, the engine’s electronic control unit (ECU) supplies current to the fuel solenoid.
Then, the solenoid allows the liquid fuel to enter the regulator.
Once inside the regulator, two things happen:
- The liquid fuel decompresses and turns into a vapor
- The vaporized propane's pressure is adjusted to between 3.5 and 5 PSI (in the case of Toyota’s). This is necessary since the fuel injector requires a precise pressure for combustion to take place
The Mixer
From the regulator, the vapor propane travels into the mixer.
That’s the component that mixes air from the air intake with fuel.
The Throttle Body
Once mixed, the air/fuel mixture goes into the electronic throttle body.
And that controls the amount of air/fuel that makes it into the fuel injector.
The Fuel Injector
After that, the mixture flows to the injector.
Inside the injector, the ECU adjusts the fuel flow and air/fuel ratio based on inputs it receives from sensors.
The Engine
The fuel injector then passes the air/fuel mixture into the engine's intake manifold.
Once that happens, a spark from the spark plug ignites the fuel, pushes the pistons down, and drives the crankshaft.
The crankshaft transmits power through the transmission and to the wheels.
And that’s ultimately what allows the forklift to move.
Additionally, the hydraulic pump is driven by the engine, allowing the mast to lift and tilt, as well as powering any attachments.
Now that you know how a propane forklift fuel system works, it’ll be easier to understand what can go wrong.
Here are some of the likely fuel system-related root causes of a no-start situation:
- Low fuel
- Fuel valve turned to the "off" position
- Improperly-fitted fuel coupler
- Clogged air filter
- Clogged fuel filter
- Bad fuel solenoid
- Leaking fuel regulator
- Frozen regulator
We’ll cover these issues in more detail in the next section.
Every manufacturer makes a different propane fuel system for their forklifts.
So when troubleshooting fuel system issues, the process will vary depending on the manufacturer, the year of manufacture, and the forklift model.
For that reason, we'll stick to Toyota propane forklift troubleshooting in this article, focusing on the Toyota 8-Series fork trucks with 4Y engines built prior to 2020.
The Propane Tank
As you now know, everything in the fuel system starts with the propane tank.
So, when encountering a forklift that will not start, the troubleshooting process should start with the tank.
Often, you can find a simple tank-related problem that is preventing the lift truck from starting.
Is There Fuel?
So the first question to ask is: Is the tank full of fuel?
Most tanks have a gauge mounted on the top.
But these gauges have a reputation for being inaccurate.
So the better way to check the fuel level is simply by lifting the tank and feeling the weight.
A steel propane tank weighs around 36 lbs. when empty and 69.5 lbs. when full.
An aluminum propane tank weighs around 23 lbs. when empty and 56.5 lbs. when full.
So if the tank feels unusually light, then it’s likely empty.
In that case, go ahead and swap out the tank with a full one.
Is the Tank Installed Properly?
The next step is to check how the tank is mounted on the forklift.
When you buy a propane tank, it can be either liquid or vapor.
Forklifts with a radiator will use liquid propane, while air-cooled forklifts will use vapor.
But most lift trucks use liquid fuel.
So we’ll focus on that fuel source for this section.
With a liquid propane tank, the pin in the tank bracket must line up with the hole in the tank collar.
That's because the liquid propane has to get sucked up by the fuel intake tube inside the tank.
And that tube must always be on the bottom of the tank to draw the fuel.
But if the tank is placed upside down, the intake tube cannot draw the fuel and the forklift likely won’t start.
It’s like turning a sealed drinking cup upside down and trying to drink it through a straw - you’ll just be gulping air!
So you’ll need to make sure the tank is positioned correctly, with the forklift’s mounting bracket pin inserted in the tank’s collar.
Action Items:
- Does the propane tank have enough fuel?
- Is the tank position properly, with the tank bracket bolt inserted into the hole in the tank collar?
Once you’ve checked the fuel level and the tank installation, it’s time to move on to the coupler.
How to Start an LPG Forklift in Cold Weather
Cold weather presents some problems for propane-powered forklifts.
As we’ve noted, liquid propane is kept under pressure in the propane tank to maintain its liquid state.
The problem is that the colder it is outside, the more the tank will lose pressure.
And proper pressure is essential for the propane tank to do its job: Acting as a fuel pump to force the fuel into the rest fuel system.
So when there’s too low of pressure, the fuel cannot move as easily into the fuel system, and the truck will be harder to start.
Additionally, cold temperatures can cause the regulator itself to freeze, which further prevents the fuel from flowing and ultimately the forklift from starting.
So the key with a no-start situation in cold weather is getting the fuel tank and the forklift warmed up.
If you do that, chances are it'll start right up.
The Fuel Coupler
Is the Tank Coupler Connected Properly?
A common issue we see with forklifts that won’t start are improperly installed fuel couplers.
These are the components that connect the fuel tank to the forklift’s fuel line.
Inside the tank-side coupler, there are two rubber components.
One is an o-ring and another is a quad ring.
What happens sometimes is that the quad ring can pop out of place.
It's easy to tell when that happens just by looking at the space between the couplers when they’re connected.
You want to see a small space between each.
But if you see a much larger space, that's an indication that the quad ring has popped out.
And if that happens, several things won’t happen:
- There won’t be a proper seal
- The forklift-side coupler pin won’t engage with the tank-side valve
- The fuel won’t be released properly
- And your forklift won't start
Fortunately, reseating these rings is easy.
Simply press the rings with your fingers back into place on the tank-side coupler and reconnect both couplers.
Additionally, it’s a good idea to keep a supply of these rings near where you store your tanks.
That way, you can quickly and easily replace them and save yourself a lot of hassle.
Is the Valve Turned On?
Once you’ve done that, the next step is to ensure the tank valve is turned to the "on" position.
Turning clockwise will close the valve, stopping the fuel flowage from the tank.
Turning counterclockwise will open the tank.
Action Items:
- Are the o-ring and quad ring seated correctly in the tank-side coupler?
- Are the couplers connected properly?
- Is the tank valve turned to the “on” position?
Now that we have the basics covered, let’s go over some important information about propane itself that you should know.
Ethyl Mercaptan: The “Secret” Culprit of Many Propane Fuel System Problems
Propane as a fuel source for lift trucks has a well-deserved reputation as a clean-burning, efficient energy source.
That said, propane itself is often full of dirt and other contaminants.
Those contaminants can be rust from inside of steel tanks, powder from the aluminum tank manufacturing process, paint chips, or any number of other particles.
Additionally, there’s another substance that’s added to propane during production: Ethyl mercaptan.
This is an oily substance used to give the normally odorless propane fuel it’s distinctive “rotten egg” smell for detection.
Normally, this substance will travel with the fuel and end up in the combustion chamber, where it will simply burn up.
But if the fuel isn’t at the proper temperature when it reaches the regulator, the mercaptan oil can separate.
We call this “cracking out.”
And when it happens, the oil can accumulate anywhere in the fuel system, including the regulator, the throttle body, the mixer, and the injector.
The result is that these components can become clogged and can result in a no-start situation.
It’s important to be aware of the existence of this oil and the problems it can cause.
Understanding that will help make the rest of the propane fuel system troubleshooting process easier to understand.
The Fuel Filter
Now that you’re aware of some of the issues with propane fuel itself, it’ll be easier to understand the role and importance of the fuel filter in a propane fuel system.
Sending dirty fuel into the engine is not a good thing.
So it must be cleaned first.
And that’s done through a fuel filter, which is mounted on the forklift’s regulator.
The fuel filter is a simple tube made of brass, copper, stone, or composite material that attracts contaminants from the liquid fuel that passes through it.
The problem is that over time, those contaminants can clog the fuel filter.
In that sense, it’s just like a coffee filter: At some point, the filter must be changed.
Otherwise, the flow of fuel will be inhibited and the forklift won’t start.
At a minimum, propane fuel filters should be changed every 2,000 hours.
Changing your forklift’s fuel filter is one of the most important maintenance items for fuel system integrity.
If you find that you’re replacing fuel filters often, that’s a good sign you have issues with dirty fuel tanks.
Consider swapping out your tanks for new ones and see if the problem persists.
But if your propane tanks are especially rusty, or the forklift is under high-use, it should be done more often.
Action Item:
- If you suspect that your fuel filter needs to be replaced, it’s best to call a qualified forklift technician. Because a forklift’s fuel line may contain pressurized liquid propane, changing the fuel filter can result in a release of that fuel. And if that happens, serious injury can result.
The Fuel Solenoid
A bad fuel shut-off solenoid could be the reason why your propane forklift is not getting fuel.
As we noted in the How Does a Propane Forklift Fuel System Work? section, the fuel solenoid acts as a “gatekeeper,” preventing or allowing fuel to flow from the fuel line into the regulator and beyond.
If there’s an issue with the solenoid, the fuel will not be able to flow and the forklift won’t start.
Some common reasons that a fuel solenoid won’t work include:
- Broken wires
- Debris from a plugged fuel filter
- Bad sensor or code from the ECU
- Bad fuel solenoid
Action Item:
- Fuel solenoid troubleshooting can get very complicated very quickly. So in these cases, it’s best to contact a qualified forklift technician to troubleshoot the root cause(s).
The Regulator
Are All Hoses Secure and Damage-Free?
If you’re experiencing a no-start situation with your forklift, and you’ve traced it to the regulator, you should first check the various hoses and tubes going to and from the regulator.
After all, propane fuel systems are very sensitive.
And something as simple as a loose hose can disrupt their function.
In a forklift regulator, you’ll find several hoses:
- Slow path hose
- Balance line
- Injector line
- Vacuum line
- PCV hose
- Coolant lines (in and out)
You can reference the image below for the location of each hose:
Check that these hoses are free of any damage or wear.
Then, check that they’re connected properly and snug.
(Just make sure that the forklift is turned off and is cool before doing so!)
Identifying hoses that are loose or need to be replaced is an easy way to solve no-start problems originating from the regulator.
Is the Regulator Clogged?
Remember the ethyl mercaptan we discussed just a few sections ago?
One of the top fuel system problems that’ll prevent a forklift from starting is when this oily substance gums up the regulator.
So when it comes to forklift propane regulator troubleshooting, the key is often eliminating the accumulation of that oil.
When the oil builds up, it will prevent the regulator diaphragm from moving properly.
Additionally, the oil can “pan fry” the diaphragm, which can cause it to fail.
And when the diaphragm is damaged or otherwise interfered with, the correct fuel pressure cannot be maintained and the forklift won't start.
So what’s the solution?
Draining the regulator.
This involves:
- Opening a valve on the bottom of the low pressure side of the regulator
- Warming the forklift up
- Allowing the oil to liquefy and evacuate the regulator chamber
This needs to be done regularly - and more often if the truck is used heavily.
REMINDER: Regulator maintenance should only be performed by a qualified forklift technician. Propane is extremely cold and can quickly cause serious injury if proper precautions aren’t taken.
Should You Rebuild Your Regulator?
In years past, it was common to buy a regulator repair kit and rebuild the regulator instead of buying a new one.
But nowadays, it’s more common to simply swap out the regulator for a brand new one.
Why the change?
Well, it's true that a regulator repair kit might cost half as much as a brand new regulator assembly.
But between disassembling, reassembling, and testing, it ends up costing more in labor to rebuild the regulator than to simply swap it out.
The good news is that with proper maintenance, regulators on a Toyota can last 10,000 hours.
But without it, the regulator will likely fail much before 10,000 hours.
Action Items:
- Are all hoses to and from the regulator connected, snug, and free of any damage? (Only check when the forklift is off and the engine is cool. And make sure to follow all safety warnings and decals!)
- If you suspect the regulator needs to be drained, contact a professional forklift technician
Propane Carburetor Troubleshooting
If your forklift was manufactured after 1999, it’ll have a mixer.
But if it was made prior to 1999, it’ll have a carburetor.
As with regulator troubleshooting, propane carburetor troubleshooting is often a matter of how filled with "gunk" it is.
After all, ethyl mercaptan can bypass the regulator and end up in the carburetor, causing it to malfunction.
So the key is to regularly drain the regulator so less of that oil ends up in the carburetor.
And that will reduce the likelihood of the carburetor failing.
The Air Filter
In addition to fuel, engines require air for combustion.
So anything that interferes with proper airflow can cause the forklift not to start.
On a Toyota forklift, the air intake is located on the rear right-hand side pillar of the overhead guard.
Air is drawn through this vent, through a series of hoses, and then through the air filter.
Like a fuel filter, the air filter cleans the air and removes any contaminants that might mix with the fuel and interfere with the combustion cycle.
In this system, we often see three problems:
- The air intake is obstructed
- The air filter is excessively dirty
- The air filter is missing
And in any of those cases, the result can be that the lift truck won't start.
So, if that’s the case, it's a good idea to inspect the air system for any issues.
Then, try starting the fork truck again.
Action Items:
- Make sure the air intake isn't obstructed
- Check the hoses and air filter housing for holes or damage
- Inspect the air filter itself and replace it if it's missing or excessively dirt
The Radiator
Many folks don’t realize how important it is to maintain their lift truck’s radiator to prevent fuel system issues.
The reason is that the regulator depends on the coolant from the radiator to prevent it from freezing as super-cooled liquid propane flows through it.
So if the radiator and rest of the cooling system isn’t maintained, the radiator can literally turn into a block of ice.
And if that happens, fuel won’t flow and you’ll have a no-start situation.
So the overall key is to keep the coolant system in the truck running at the proper temperature, and filled with an adequate amount of coolant.
If you do so, you can do a lot to expand the longevity of your forklift’s fuel system components.
Action Items:
- Is there enough coolant in the radiator? (Only check the radiator coolant level when the engine is cold!)
- Is the radiator free of dirt and debris?
There’s a lot that can go wrong with a forklift propane fuel system.
That’s why proper and regular forklift maintenance is absolutely key to making your forklift function well and last a long time.
If you’re having trouble maintaining your forklift or your fleet, it’s best to reach out to an authorized service center for help.
Conclusion
There you have it: the complete step-by-step guide to troubleshooting a Toyota propane forklift's fuel system.
But now we'd like to hear from you.
Were you able to use this guide to fix your propane forklift?
Do you have more questions?
Let us know in the comments below!
Thanks for the tips, I’ve recently just started working on Lp forklifts . Making the transition while I get my automotive shop built. But unfortunately I’m working with a company that wants to do every possible cause before possibly purchasing any repairs. But I guessing that is do to the age of the equipment…. I’m 40 yrs old and the equipment is about my age .
You’re welcome Wayne – we’re glad you found the tips useful! And best of luck to you as you navigate your new opportunities!
Thanks, for the very informative, easy steps,,many people can do it ,even people that has no knowledge about propane powered equipment, God bless 👍,
You’re very welcome Stephen – we’re glad you found it helpful!
8FGU60 starts hard in the morning after the tank has been off overnight. Though I never hear a rush of propane like something is bleeding off overnight. I usual crank it for 5 or 6 seconds then stop. Some mornings it takes 6 or 7 times before it stumbles to life. I’m going to check the filter and check on draining the regulator. But if there is any other thoughts please let me know. This happens with new bottle and it always starts but it’s not getting better and we have no backup. Thanks
Hi Patrick, thanks for the comment!
You’re on the right track by checking the filter and draining the regulator first.
If that doesn’t help, it may indicate an issue with the regulator itself.
In that case, we’d recommend you reach out to your local Toyota dealer for help.
Good luck!
It’s mercaptain buildup on the mixer and throttle body.
Yes very helpful in no fuel cases, but if to much fuel is coming out of the breather when you turn the key on ,vaporizer is good lp fuel solenoid is good, and grounds are good .Then what Nissan K25l engine
Hi Vince,
I’m glad you found this post useful!
On your question, the Nissan K25 fuel system is OEM-specific and uses a special injector and regulator.
So unfortunately, the only way to properly troubleshoot it is with an OEM laptop.
That means you’ll need to reach out to your local Nissan dealership for a diagnosis.
I hope this helps!
Cheers,
Alex
1978 Caterpillar 8k Fork Truck, w/ 4-236 Perkins, Century H-1477B LP system. The regulator has been removed cleaned and reinstalled. Prior to removal the engine would not start was suspect trash in the fuel system. The fuel regulator / converter was pretty gummed up. A rebuild kit was not used. After reassembly the engine appliers to be flooding out. If the bottle is turned on momentarily then off long enough to charge the line w/ fuel it will start. Then crack the valve at bottle the engine stumbles and stalls. A fuel smell from the air filter housing. The engine will not restart until all the fuel has dissipated and process repeated. I suspect the installing a rebuild kit in the regulator will correct the problem. What is your recommendation.
R/ Kevin
Hi Kevin, thank you for your question. Here’s our answer: You are correct that there’s too much fuel. By using the LP tank shut off valve, you’re in effect cheating the system to find the correct fuel mixture to start. And once you’re running in a rich condition, you’ll continue to run the engine with high CO. So our recommendation is to install a new regulator. I hope that helps!
For the last 2-3 days we are having to drain the evaporator daily due to the oily sludge. After we drain it runs good for about 4-6 hours then repeat. I.price a new evaporator about $650.00+. Before i buy is there a way to spray cleaner in the drain hole and clean it out without taking off the forklift
Hi Al – thank you for the question.
The regulator should be at coolant operating temperature. That way, when you remove the drain plug, all the oil should be liquid and totally drain out. On your question about spraying cleaner, you could spray Sea Foam in that plug and let it drain out. To get to the root of this problem, you may want to check with your LP supplier about the quality of the fuel. It’s also possible that you have a bad LP tank.
I hope this helps!
Yale forklift will not start cold. Changed regulator,didnot solve problem. Spray either in throttle body & it starts. After it warms up, it starts good. All hoses are good, got gas going in regulator. Ther are no problems after start up?
Hi Sammie,
It sounds like the problem may be that the propane tank is getting too cold outside and losing pressure. If it’s possible, try to bring the propane tank and the forklift itself inside to warm up and see if that helps.
Excellent forum,Very informative,Love it!!
Hi Todd,
Thank you for the compliment – I’m glad you found the article useful!
Hi Alex,
My Toyota is 7FGCU25. It keeps stalling when the temperature is below 50F and It is doing fine in room temperature. Just wondering where I should be looking at? Is the regulator and vaporizer the same thing? Also, how do I check fuel filter? The forklift is unused overnight. Is it safe to open the fuel filter?
Hi Ryan,
The regulator and vaporizer would be the same thing. We wouldn’t recommend checking the fuel filter yourself because of the potential dangers of the cold propane gas. It’s best to have a qualified forklift technician do that for you. I hope that helps.
Above comment states: “Spray either in throttle body & it starts.” I am researching the problem on my LP Onan Generator, 2500 Watts, which does not start, although it has a strong starter sound. Do you find the use of ether to be acceptable to determine if the fuel supply may be the problem? I will definitely follow your other points to check on the causes of the non-start issue. Thank you very much for your insight in the operation of a LP engine. If you agree, do you have a source for the ether spray bottle?
Hi Henk,
As far as using ether goes, I found this great article from Amsoil on the topic: https://blog.amsoil.com/is-starting-fluid-bad-for-gas-engines/. Thanks for reaching out!
My Yale forklift will run for about 45 mins to an hour and then keep shutting down. We have replaced both the regulator and the throttle body.
What is your suggestion.
Hi Jason,
Here’s what our technical team suggests regarding your Yale forklift that keeps shutting down:
Without all the specific details of the forklift (age, fuel system, electrical and control system) it will be impossible to give a specific answer. But we do use a training and diagnostic tool that should help get you headed in the right direction. The acronym “FACTS” are the basic requirements for an IC engine to run, and stands for Fuel, Air, Compression, Timing, and Spark. If you can determine which one or ones of these items is missing when the engine will not run, you will be able to zero in on what the cause is.
I hope that helps.
Cheers!
Good Day and thank you for the great info. We have a TCM lift that cranks and starts great but after warming up seems to just die after idling very low. Any ideas where to start?
Hi James,
Here’s what our technical team suggests regarding your TCM forklift that keeps shutting down:
This sounds like it is likely a tuning issue. You will need to confirm the proper condition of all ignition parts. Confirm there are no restrictions in the air intake of fuel system. Then you will want to tune the carburetor/ mixer for proper engine RPM and fuel mixture. If this does not resolve the issue, the problem may be more complex and will require the expertise of a trained technician.
I hope that helps. Cheers!
What is the electronic unit that “Slow path hose” is connected to on the throttle body?
So I just learned that it is “air fuel ratio controller”
Brilliant site, thanks for all the trouble you have taken.
I have a Toyota Tonerro HST 1.5 5 years old which is used about 30minutes a month. Annual service by Toyota.
Using a 38kg gross 18kg of gas net I get about half a cylinder of gas used then the truck just stops. Change the cylinder and it starts easily. Tried to get some input from Calor Gas, but no help. I would like to get some idea whats wrong to reduce the time the Toyota engineer is here as the cost can be breath taking!
Hi Eddie,
Thanks for the compliment! Here’s what our technical team suggests: The first thing that will need to be done is to confirm there are no restrictions in the fuel system. LP tank coupler is functioning properly, fuel filter is clean and all fuel lines are with out restriction. Once these things are confirmed you will then need to start diagnosing the fuel system itself which will likely require the expertise of a qualified Toyota technician. I hope that helps and thanks for reaching out!
water from radiator is getting into the carbie it presurises the radiator could this be the regulater
Are you able to provide the make, model, and engine type of your lift truck? Also, by “carbie” I’m assuming you mean the carburetor?
Toyota forklift will only start with pressing pedal halfway to the floor and it will stay running as long as i dont take the foot off the pedal. It will then sputter and stall. Fuel filter looked clean and lines looked good. Any idea?
Hi Gene, here’s what our technical team recommends: Depending on the model and the fuel system some adjustment may be able to be made to get the proper fuel mixture. You will want to rule out other items including…proper operation of ignition system, correct compression and timing, no restrictions in the air intake and filter. Thanks for reaching out!
Im working on a old nissan that Use to start and run and then quit, new vaporizer installed and now wont run at all, have propane at test port but nothing coming out of vaporizer, can blow through old vaporizer from inlet to outlet but can not blow through new vaporizer at all from inlet to outlet, should I be able to blow through ? im starting to think the new vaporizer may have a blocked passage.
Hi Ethan, here’s what our technical team says: You should not be able to blow through the vaporizer (regulator) as you described. Make sure there are no leaks or restrictions in the secondary fuel lines going from the vaporizer to the mixer assembly. Thanks for reaching out!
Wow, that is the comprehensive and understandable illustration I have ever seen. Great Job Been a mechanic for 40 years and did know propane systems had a fuel filter. Thanks for the advice.
Hi Dan, thanks for the kind feedback — I’m glad you found this article helpful!
What would cause the regulators to freeze up on a Nissan lift? Cranked up first thing this morning and ran for a few minutes, lift started sputtering like it was out of fuel. Lifted seat and regulators had frost on them.
Hi Jason,
Normally, the coolant hoses (which carry coolant heated by the engine) run through the regulator and the heat helps prevent the regulator from frosting up. So, if you’re seeing frost on the regulator, it could indicate an issue with the radiator and/or coolant lines. You might want to first try blowing out the radiator, as debris clogged within the fins can interfere with the whole system. Then, see if the frosting problem improves. I hope that helps and thanks for reaching out!
From Australia…. I have a Crown CG25E LPG forklift. (purchased new in 2014.)We have had issues on startup where the engine runs roughly for a few minutes, then runs OK til next startup. It is used approx ten times a day, sometimes no missing after second or third startup. I have had a Crown technician on-site twice and both times he has removed air filter and cleaned with compressed air. Have spent $500.00, but problem still persists. I checked oil yesterday and level was not far off full, but decided to top up. When i removed oil filler cap there was a significant deposit of yellow sludge on the inside of cap? Any thoughts please?
Hi Stuart,
Here’s what our technical team says:
There are two separate issues. The running issue sounds like it could be a fuel system issue. Possibly from deposits and sludge build up in either the regulator or throttle body or both. The fuel system will need to be serviced. Disassembled and cleaned or even replacement of parts.
The yellow sludge is an indicator that there is moisture mixing with the oil in the crankcase. This can come from condensation which is typical from a unit that is regularly ran for short periods of time. It will be very important that they continue to have this unit serviced and replace the engine oil regularly, even if the hours do not indicate that it is due for service.
1) Hyster H120XM stuck in an icy rut
2) ran out of propane, engine shut down and would not turn over again. Battery power is strong. Towed inside.
3) found ignition and starter fuses blown. Replaced and started fine
4) running outside next day and after 5 minutes, engine shut down again and now won’t restart. Battery is good. Haven’t checked fuses again but something isn’t right. Could it be the fuel solenoid? Starter solenoid?
Hi Brian,
Here’s what our technical team suggests: If the starter and ignition fuses blew there is almost certainly a shot circuit in the system somewhere. The fact that it is intermittent and related to operation out side would lead me to believe there is likely a bare wire or component that shorts out when it is jostled around. Inspect all wiring and circuitry related to the blown fuses. I hope that helps and thanks for reaching out!
Thanks guys. There was indeed a broken wire in the fuel solenoid. We replaced it but in doing so broke the 90 degree elbow which was threaded into the regulator. Then we had to drill and break the broken piece to extract out because it could not be turned out. We chased the thread with a good tap to clean it, and put a new elbow in. Upon starting it we are now blowing liquid gas past the regulator into the air breather assembly – it is filling right up. It seems to me the regulator isn’t functioning properly now. We may have damaged it trying to drill the broken fitting out. Do you concur? A new regulator and we should be in business??
Hi Brian,
Our technical team concurs: It sounds like the regulator is not functioning properly. Thanks for reaching out and good luck!
i have still forklift
start well.after 30 sec it cuts off
any suggestion
Hi Charlie,
Here’s what our technical team says: This sounds like it is likely a fuel-related issue. Verify there are no restrictions in the fuel system, including proper operation of the shut off system and LP filter. I hope that helps and thanks for reaching out!
thank you this has been grate in assuring my diagnose dough mi FL is an older model w/ carburator fuel gets to the first diaphragm an not to the second
Hi Fernando, I’m glad you were able to use this article to help diagnose your forklift! That was our goal, so I’m glad you shared with us!
Hyster H50XM won’t start reliably in cold weather. I had the whole engine serviced by dealer and they replaced the diaphram. Still having the same issue. it is considerably colder at my place than at the dealer.
Hi Mark,
Here’s a response from our technical team: There are many factors that contribute to the engine running properly. IE…Fuel, air, compression, timing, spark. Depending on the age and the particular fuel system on your Hyster, it may be necessary and possible to adjust the fuel system so the unit will run and start properly.
I hope that gives you some direction and thanks for reaching out!
Like other people have commented. Great page and very useful. Here is what I have going on. My Hyster forklift is running lean, slower to respond when the throttle is pushed, rough idle, and as others noted, it is hard to start upon the first start. Room air temp set to 55* F
Here is my question, what do the three different fuel lines do? Balanced, slow, and injector? I removed the balanced line from the air intake side and immediately it was working. Very responsive, good idle, etc.. But if any pressure was put into that end or any pressure was pulled from that tube it would immediately stutter and die. So I just left it disconnected and no problem (temporarily). Between the air intake connector end and where it connects to the regulator, there is a black box 2x2x4 inches that feels and sounds hollow. I believe it is a vapor fuel box of some form. I have tried to check everything else you recommend on here with no luck. It seems that disconnecting this hose has been the only thing that has worked so far. I really appreciate your help.
Hi Josh,
What is referred to as the “slow path” line is the low pressure line that runs from the regulator to the fuel injector. There is a vacuum line that is attached from the air intake to the regulator. The empty box you are referring to is a vacuum accumulator. It sounds like you have done most of what you can and it may be time to reach out for a qualified service technician. Thanks for reaching out!
thank you for the article
You’re welcome!
Hi There…Great troubleshooting information. I have gone through everything several times with no results. The mixer has been changed out, the fuel solenoid has been changed out, the carburetor has been cleaned. Everything appears to check out. Still wont start. As you try to start over a period of time the mixer starts to freeze up. Also if you choke off the air from the air intake, it seems to start to fire..but still no starting.. I’m not sure what would be left to go through. Any ideas? Thanks
its a Hyundai model 4G64
Lorne
Hi Lorne,
If you have not already, you will need to confirm all other systems are working properly. IE…air, compression, timing, spark. Once it is determined it for certain is an issue with the fuel system you will want to confirm proper connection of all hoses lines and fittings. Ensure there is a properly filled LP tank, and fuel coupler and filter are not obstructed. Your next steps will vary greatly depending on the particular fuel system. You stated that the “mixer” was replaced. Typically the carburetor or throttle body assembly can be referred to as the mixer. When you stated mixer are you referring to the regulator?
Is that electronic part called an FCM Step Motor?
Hi , we have a toyota that will not start unless we shut off the propane tank . We did notice that when you turn the key to the on position without turning the engine over , propane is flowing to the throttle body . would this be a bad ecu or I saw something about a crank sensor at the distributor . Any help would be great , Thank you
Hi Lou,
If fuel is flowing through the regulator when the engine is not being turned over there is likely an issue with in the regulator itself. You’ll want to contact your closest authorized service center for help troubleshooting further. Thanks for your question!