Yamaha 4 stroke impeller maintenance
 

Basshound wrote:
I have a 2005 Yamaha 9.9 High Thrust outboard. It probably has about
100 hours on it. In looking at the maintenance intervals in the owners
manual, and there is no interval specified for replacing the water
pump impeller. It only says that the "dealer" should "inspect" it at
200 hours. Seems to me that inspecting it would be as much labor as
replacing it. I can buy a replacement kit including the impeller,
housing, etc for about $35. Do I need to change it every year? Every
Two years? Have the impellers improved (Better materials) to the point
where they only get changed every 5 years? I don't want to get
stranded, but I also don't want to change the impeller every year if
it isn't really needed. If the "real" recommendation were something
like 5 years, I'd probably do it at 3 or 4.

Thanks,
Kenny

It depends on your boating conditions. I replace mine every 100 hours,
or so, due to the sand that can be stirred up and ingested by the motor
in the area I boat. It's cheap insurance when you consider the expense
and inconvenience of an overheated motor.

If you are running it in a deep, clean, lake you should be good with 200
hours or more. Shallow waterways, murky rivers, etc. will tear it up a
lot sooner.

Dan