Impco is a manufacturer of fuel system components for alternative fuels like LPG/propane gas. You’ll find Impco in a variety of forklift brands like Hyster, Clark, Yale, Cat, and many others.
The most popular Impco regulator is a model J. Here’s a picture of it below.

We offer a few different versions of the model J
Model JB The B stands for blue spring. This is by far the most common model J regulator. The blue spring offers negative 0.37 kPa (1.5 inches w.c.) The Impco model JB diaphragm is made of hydrin and is suitable for most applications.
Model JB-2 is similiar to the JB–only difference is that the diaphragm is made of silicone and is suitable for cold climates.
We offer a generic model JB which has a primer button. Some old models of forklifts still have a primer button on the LP regulator and we’re one of the few online that offer this version.
REBUILDING MODEL J REGULATORS:
You can repair and rebuild model J regulators using repair kits made of hydrin or silicone. There’s no limit to how many times you can rebuild a model J regulator.
COBRA
Impco developed the next version of regulator after the model J and called it the model K. Impco but quickly changed the name to COBRA after learning that the US trademark office would not trademark an alphabetic letter. The COBRA will work perfectly in place of a model J. COBRA will work for a model J application but model J should not be used for a COBRA application.
We offer COBRA repair kits and yes you can rebuild COBRA units as many times as you wish.
COMMON QUESTION: My forklift came with a model JO. Can I use a model JB or JB-2? Yes–as long as you understand the difference between hydrin and silicone there’s no problem.