A forklift LPG regulator (also called a converter or vaporizer) drops high tank pressure to near-atmospheric, then vaporizes liquid propane into gas using heat from the engine coolant so it can feed the carburetor or mixer. ForkliftIQ supplies Impco and Aisan-style single and two-stage converters, matched by engine model and fuel system rather than by forklift model alone.
Replacement LPG regulators and converters for propane forklifts, matched to engines from Toyota, Nissan, Mitsubishi, GM and more. ForkliftIQ ships complete converters, lock-off assemblies and diaphragm repair kits factory-direct, with OEM cross-reference support and a fast parts quote.
What an LPG regulator/converter does
On an LPG forklift, propane leaves the tank as a pressurized liquid. The converter has two jobs. First, a primary and secondary stage reduce that pressure in steps down to roughly atmospheric so the fuel can be metered. Second, it acts as a vaporizer: engine coolant is routed through the body to add heat, boiling the liquid propane into a dry gas before it reaches the mixer or carburetor. Because vaporizing propane absorbs heat, the coolant loop is what stops the unit from freezing solid during operation.
Because the converter sits between the tank lock-off and the fuel mixer, a fault here affects starting, idle and power under load. It is one of the most common LPG driveability parts to service.
Signs of a failing converter
Typical failure symptoms include hard or no starting, hesitation and stumbling under load, rough idle, and black smoke from an over-rich mixture. External icing or frost on the body usually points to a coolant-flow problem, since the unit is no longer getting enough heat to vaporize the fuel. Coolant found inside the converter, or leaking from the diaphragm covers, means a ruptured internal diaphragm and calls for a rebuild kit or a complete replacement.
- Hard starting or no-start on LPG
- Hesitation, stumble or power loss under load
- Black smoke / rich-running condition
- Icing or frost on the converter body
- Coolant leaking internally or from covers
- Rough idle after warm-up
Types: single vs two-stage
Forklift converters generally follow one of two Impco or Aisan-style designs. Single-stage units drop pressure and vaporize in one body and are common on smaller or older engines. Two-stage (primary/secondary) converters split the pressure reduction across two chambers for smoother metering and better cold-start behaviour, and are the norm on many modern IC LPG trucks. Some fuel systems integrate the lock-off solenoid into the converter, while others use a separate lock-off; identifying which layout your truck uses matters for correct fitment.
How to identify the right unit
Match by engine and fuel system, not by the forklift model alone. The same chassis can ship with different engines (for example a Toyota 4Y, Nissan K21/K25 or a GM 4.3L), and each may use a different converter. Read the casting marks or ID tag on the old unit, note whether it is coolant-heated, and record the mounting pattern and hose/port sizes. Send us those details with a photo and we will cross-reference a compatible converter.
We list parts as compatible with named brands and engine families; they are aftermarket replacements, not OEM-branded unless stated. Impco and Aisan are referenced here as generic design styles for fitment, not as supplied trademarks.
Compatibility & sourcing
ForkliftIQ sources LPG converters, lock-offs and repair kits factory-direct from verified suppliers, covering common IC engine families used across Toyota, Nissan, Mitsubishi, Hyster, Yale and Caterpillar propane forklifts. We can quote a diaphragm and gasket kit for a rebuild, or a complete converter assembly.
We dropship worldwide on FOB or CIF terms. For exact port sizes, stage configuration, kit contents and pricing, request a quote — we confirm fitment against your engine and fuel system before shipping rather than publishing specs we can't guarantee.
| Attribute | Detail | Match on |
|---|---|---|
| Function | Pressure drop + vaporize (coolant-heated) | Coolant lines present |
| Single-stage | One-body reduce & vaporize | Smaller / older engines |
| Two-stage | Primary + secondary chambers | Modern IC LPG trucks |
| Engine family | e.g. Toyota 4Y, Nissan K21/K25, GM 4.3L | Engine + fuel system |
Frequently Asked Questions
How do I identify the right LPG regulator for my forklift?
Match by engine model and fuel system rather than by the forklift model alone. Send us your forklift brand, engine (for example Toyota 4Y, Nissan K21/K25 or GM 4.3L) and a photo of the old converter with any casting or tag numbers, and we'll cross-reference a compatible unit.
What are the signs of a failing propane converter?
Common symptoms are hard starting, hesitation or stumbling under load, black smoke, external icing on the unit, and coolant leaking internally or from the diaphragm covers. These usually point to a worn diaphragm, failed valve or a torn primer, and the converter is often serviced with a repair kit or replaced as a unit.
Can you cross-reference an Impco or Aisan-style regulator?
Yes. Many forklift LPG converters follow Impco or Aisan-style single or two-stage designs with shared mounting and hose connections. Give us the OEM number, casting marks or the old unit's dimensions and we'll match an equivalent compatible aftermarket part.
Do you supply repair kits or only complete converters?
Both. For many units we can supply a diaphragm and gasket repair kit, a complete converter, or a lock-off and vaporizer assembly. Tell us whether you want to rebuild or replace and we'll quote the correct kit or complete unit.
Need this part fast?
Send the engine, casting number or a photo — we cross-reference and ship LPG converters worldwide.
Request Parts Quote →← All forklift parts