I haven't had my boat long enough to tell you from experience how long an impeller lasts on a D6. Regardless, it's probably not a bad idea to change them every other year or so or 100 hours. I carry a spare with me at all times and the tools to do the job, not that I'd want to tackle it in the middle of the lake. From my experience with Mercury products, impellers, unless they are just burned up from lack of water due to a blocked intake or drives trimmed out way too much, tend to deteriorate over time, losing bits as opposed to total failure all at once. That's why I switched to the clear strainer tops. You can actually see the impeller with a flashlight and you can also notice if any bits of a vane have broken off because they will be floating in the strainer.
Jetmart, I've never heard of breaking in a water pump impeller. Just start the engine and let it pump. The factory specifies lubing it with glycerin so it doesn't start dry. After running a few seconds, it should be pulling water and that's what keeps it from burning up. Probably a good idea to run at idle for awhile and slowly bring the engine up to operating temperature, but here in Lake Michigan, my engines don't really warm all the way up until I move out of the harbor with at least some load. Again, the clear strainer cover lets you see first hand that it's pumping water. As for going into forward and reverse, that doesn't matter because the impeller is running off the engine and only goes in one direction regardless of which way the props are turning.
Anyone find the torque specs for the rear cover bolts?
Clyde
