This is an LPG powered model with i think a Peugeot petrol engine fitted, on a brand new bottle with the choke out it starts instantly, but once a little pressure has gone from the bottle, it has to be cranked over for maybe 10 or 15 seconds.

On what i can only describe as older looking/heavier style (UK) bottles, it wont run when theres roughly around 1/4 of the bottle left, putting the bottle onto my Nisan forklift and it runs quite happily.

Currently the Caterpillar has a newer bottle on which feels quite empty and it's running quite happily on it.

The Caterpillar sems very heavy on fuel as well, the Nissan is a far heavier truck and seems to run far far longer.

Can anyone suggest what could be causing these issues ?