Is it slow to crank with ignition off or only when you throw the fire to it? My 15-1 b-1 motor would get a little hard to crank whe you put the ignition to it and at 25 degrees of start retard it would back fire badly I ended up with 10 degrees start retard seemed to be perfect. Mine has 350lbs on the seat and about 900 open so it has big springs as well. probaobly not as big as predator but close.