After looking at reviews perhaps the propane Lehr motors have some quality control issues. A lot of positive and negative reviews makes it seem like you roll the dice when you buy one. Perhaps a regular 5hp motor would be the way to go.
Of course an electric motor is still an option and perhaps if you go to electric only lakes it is the best option.
Casting Call
5 meter RIB rolls up nice, five air chambers, max load wt. 1900 lbs. Row or electric, your choice. Tony
Golfbum
I have a Sea Eagle Foldcat 375fc with 3 hp outboard, front trolling motor, might work out for you.