The Lifan 152F-3Q is a 79.5 cc OHV 2.5hp motor. Rated @ 3600rpm. It's a keen little motor. I'm under no illusions of having a 2.5hp mud motor, but rather a shallow water, air cooled form of mobility that doesn't involve paddling.
I build layout/marsh boats trying to maximize the efficiency of the hull thru shape and weight reduction. Hence not wanting to put anymore weight on the transom then absolutely necessary. The 5x5 I tried first surprised me by requiring such deep water to hook up. I didn't gps the 5.5x5 but it will put the boat on step..... Barely.
Mark, I agree, gear reduction would help, and very well may happen after sunday when our season closes. I really want to get this prop thing figured out tho first, as I doubt I"ll build a longtail for use with these motors. A shortail @ 50lbs would be good tho. I guess my thought is if I can get it to run how I want it to as a longtail then tweaking the same motor into a shortail should be fine as the gear reduction will only help. And if I can't, then the addition of 20 lbs. for a 6.5hp motor isn't optional.