In my experience, and I'm certainly no expert on the stuff, but propane engines are in my opinion the most finicky for the mixture to be "perfect", that includes both starting and running. Most vaporizers/regulators now days don't really have mixture adjustments to "dial it in", like all carburetors EPA laws have really restricted what you can "tweak" on them. With that said, my advice, don't try to "wing it" with a "might fit will fit", pay the extra bucks for the OEM replacement regulator, whether Cat, JLG, Clark, whatever. And don't bother with rebuild, I've wasted too much time with that, just replace. And that includes the vacuum lock off if it has one. Older regulators had a primer button for starting or a solenoid to operate the button from remote locations, like an operators seat or aerial platform, those days are gone, again, thank you EPA. Probably the best for starting is the Beam regulators, they have an adjustment screw they call "idle", which it's really not, it actually assists in starting if it's adjusted properly. But again, my advice, if it's aged, replace it. And replace with OEM parts. Propane is picky, and "will fit" don't always fit.
