Replacing impellers? When based on age?

Was wondering about impellers in my water pumps ... I repalced all impellers in teh pumps when we launched the boat in July 2006 and we have now put only about 100 hours on the boat since then.

Considering our boating is in crystal clear and clean fresh water only. No sand mud or muck whatsoever. I was wondering:

- Do impellers need to also be changed based on their age even when hours are low? Mine are two eyars old now.

- How often should they be changed when age becomes more of a factor than hours?

Merc dealer will tell you every 3 years or 300 hours. being that this is the heart of your motor and that running cool is important to long engine life. it's all up to you.

my philosophy is pay now or pay later either way your going to pay. I would rather pay a little know than a lot later.

here is FL I do my own every season weather it needs it or not, but we do have very shallow silty and sandy bottoms.

Three seasons. They can lose elasticity and start to take a shape after that. Could lead to broken vanes and occlusion somewhere down the pike. Don't overlook them. Not that hard a job if you're handy but expect to pay about $350/engine if you hire a pro. If you do it yourself, I suggest pre-medicating with at LEAST 400mg of Ibuprofen 1 hour before you pull the first hoseclamp off.

WE have replaced ours every third season and seems to have worked for years.