Changing the impeller I found it to be missing pieces, and after what I thought was a thourough search of the forums i haven't found my answer. I've removed the thermostat housing, replaced the stat, and found no pieces of impeller there and all openings are clear. I've cleared all hoses and no pieces there. I've read the overheat guide Don has posted, but I'm confused about what it says about backflushing. It seems the guide only back flushes from the intake side of the raw water pump to the intake of the outdrive. Can you backflush from the thermostat opening throught the block, back through the water circulation pump to insure no pieces are floating around in the block? Would you have to remove the circulation pump to do this? If pieces made it to the water circulation pump, would the be chewed up smaller and hopefully passed through the risers and exhauist, or would they pass thru in whatever size they broke off in and potentially be stuck in the block. This is a new boat to me and the owner said he had not changed the impeller (3 years he owned it) and during the water test everything seemed to be operating fine (within temp) even with the damaged impeller. The exhaust manifolds were not overly warm (could hold my hand on them) indicating water was flowing there. I don't think I have any over heat issues, I just wanted to zero all the items I could so I could start a maintenance program on the boat. Thanks for any help offered.
