"James Gemmill" gemmilljim@hotmail,com wrote in message
...
Is it necessary to replace the water intake impellor every year?

Necessary? No.

A good idea? Maybe.

A lot depends on the type of engine you have, where you boat, and other
habits. For example, if you have a trailered boat and you routinely start
the engine while the boat is on the trailer then your impeller will need to
be replaced often. If you have an inboard and the boat is always in the
water (and therefore the pump rarely loses its prime) then the impeller can
last many years.

A real deciding factor can be the ramifications of it failing. If you are
twenty miles off shore in a boat with a single engine and the impeller is in
the outboard/outdrive lower unit having the impeller fail can be a serious
problem. On the other hand, my tournament ski boat has a center mounted
inboard and I can change the impeller in about 10 minutes using nothing but
a screwdriver. I carry a spare impeller with me so having one fail is no
big deal.

If you have a large boat that has to be hauled out of the water to change
the impeller then I wouldn't pass up any opportunity to do so. For a
typical runabout I would go two or three years before I changed it just
because.

Rod