Johnson Evinrude 40 48 50 HP two cylinder outboards should only be run on a hose sparingly for a very scary reason. These motors can at times " run off " by themselves , by this I mean with out back pressure the engine may start to rev all by itself to the point of running at WOT, I have seen this twice in person and let me tell you that is the scariest thing you will ever see, key off, kill switch pulled and motor running 5 grand on a hose. The only way to stop it is turn the key back on and push in the choke which with the primer system it basically floods out the motor. In all my years of working on these motors, mid 80's on I only run them on the hose as needed, every thing else is done in the water at the ramp