Well, the "good news" is thats not normal, which means it's fixable.
A hot restart should be in the 2 second range for the GM 4.3L.
Where in the US are you located?
My speculation is you have a regulator gummed up with "heavy ends". It's a tar like substance that makes the internals of the regulator act slowly.
If you're willing, I'd like to send you a regulator "repair" kit. Not sure if it's been released by Doosan US yet, but if youre game for it I'll send it to you. Basically you remove the regulator, take it apart, clean the tar out with carb cleaner and put it back together with the new gaskets in the kit.

2550 hours on a GM V6 Vortec. It doesn't matter cold or hot by more than a second or so. More when cold but if you shut it off, wait and try and restart it still takes 4-5 seconds of "crank" time before starting. According to our LP guy, no and I only have this problem with this one lift (one of it's kind in the fleet).

Joe D.
How many hours are on the truck?
Is that a Hyundai 2.0L or a GM 2.4L?
When the truck is "cold" (not started in the past 8 hrs) how long does it take to fire from the time you start cranking?
When the truck is warm, how long does it take to fire?
Are you in a area of the country that has high propylene content in your propane?

F.F.

I understand the prinicipal behind it but on all my other LP lifts the engine actually starts in approx. 2 seconds of "crank" time but on this Vortec it takes more like 4-5 seconds of "crank" time. The entire ignition system is new and no vacuum leaks. I talked to the factory after the discussion here and was told that yes, the added delay in spark from the coil is designed in for the very reason you stated.

hey joe, even modern cars with emission systems, do not get fire to the ignition coils until the ignition computer has seen at least 1 full revolution (#1 cylinder tdc 2 times on the crank shaft sensor). on units with GM HEI, this helps prevent a "roll back" where the ignition spark from the key moving between run and start causes the ignition of any combustible material in what ever cylinder was close to TDC on the compression stroke when the engine stopped last, and because that cylinder has not yet hit TDC, the engine rolls in the wrong direction, just as the the starter bendix hits. this is why some 4.3 GMs (among others) have a starter bracket that mounts to the back of the starter.
But.... that 2 revolutions happen so quick there is no way -that- adds to any cranking time that anyone should be able to notice, unless you were looking for spark from the coil wire.
have you taken vacuum measurements?
have you measured engine crank speed?

I have the same problem with a Clark CGC70 w/ Vortec. I posed the question here awhile back as when you start cranking there is no spark for the first couple of revolutions on the crankshaft meaning seriously extended cranking time before the thing will actually fire up. I was told this was to prevent pre-mature ignition or some such. I seem to remember some horror stories posted about blown valves and such. I told my operators to deal with it but it's **** on battery life.

doesn't this unit have an oil pressure safety switch, and requires engine oil pressure to build up before the ignition gets spark? you might try checking and changing the oil and correct oil filter (not the cheap store brand, but get OEM or better quality filter, as the better quality filters will have check valves that can help hold some oil and maybe even pressure in the filter), using the correct spec oil, getting a battery of the correct cranking amps so that the motor spins fast enough to build oil pressure.