the regulator did have a leak that allowed a smell and a light hiss in the intake.
rebuild kit ordered.

thanks

I have observed that 8F models with 4Y engine develop a "long crank time" issue as the LP regulator ages. We have determined this to be caused by the secondary valve becoming leaky which will permit the primary fuel chamber to empty through the secondary valve while the engine is shut off. This effectively "floods" the engine and makes it necessary to crank the engine for a long time while holding the accelerator to the floor, or wait long enough for the engine to just clear itself (could be hours) after the primary chamber is fully depleted and the engine has vented the excessively rich mixture.
Sometimes you will be able to detect the smell of LP odorant at the intake air grille on the right side rear overhead guard pillar when the secondary valve is not seating.

Will the unit start on either?

yep, does sound like it may be a gummed up regulator
try cleaning it first? before replacing that pricy component?

just a thought ;o)

I did check for spark and fuel.
I will probably change the regulator.

Sound like an ignition coil. I;ve had the same symptom on my Clarks. Check for spark from coil. I picked up this nifty spark checker that you don't have to disconnect the wire. You just lay it on the side of the wire while cranking the engine and it picks up the voltage.

crank not start.
LPG
4Y engine

What are the symptoms when it won't start- won't crank, cranks but won't catch, etc? What engine's installed- what fuel is used?