A friend told me of a trick he used on free-flight gas-powered model
airplanes. If the motor he had was too big and he wanted to reduce the
speed of the model, he would install the prop backward.
Harry Gordon
P14 #234, Manatee
Mountain View, CA
><< One
> concern of mine is the possibility of re-installing the propeller on
> backwards. >>
>
>On MOST outboard motors, it would be extrememly difficult to mount the
>propeller on backwards. Especially the smaller (3.5 and below) engines. The
>prop will usually be smaller on the aft end. Not only that, but most engines
>turn the prop 'right-hand', (or clockwise) if looking at it from behind.
>
><< Obviously the boat will run the opposite of expected, but what
>kind of damage is possible? >>
>
>If you are 'lucky' enough to get the prop to go on backwards, it may go
>opposite of what is expected. You may also immediately catch the prop on the
>skeg (the little fin on the bottom of the O/B) Most smaller engines use a
>composite prop, which would tear a blade off.
>
>If by chance you do get your prop on backwards, and the motor runs without
>err, you can still cause internal damage to your lower unit. All the guts in
>there are designed to have the forces and pressures on certain components.
>Even a motor with a reverse gear, wouldn't last all that long going in
>reverse all the time. Some motors use a 'thrust bearing', which alleviates
>the thrust from the internal parts of the gearcase, and transmits it to the
>stronger parts of the outer housing.
>
>If putting a prop on backwards is an issue, use a scratch awl, 'sharpie pen',
>or even a dab of white-out on both the prop and the lower unit to mark which
>way it goes BEFORE removing the prop....
>
>Cheers,
>Russ de Ment
>Borrowing Grandpa's P-19
>Silverdale, WA