Problem started with chewed up impeller. Replaced impeller, still no water flow through the outdrive. Figured I had some blockage, maybe chewed up impeller rubber pumped through heat exchanger and/or manifolds/risers. Took heat exchanger apart, all clear. Replaced manifolds and risers. Still no water flow through the outdrive. Disconnected inlet hose at water pump and ran water back through the outdrive water intake via garden hose, no blockage there. Reconnected inlet hose at pump and disconnected other end of inlet hose and ran water through the pump, heat exchanger, manifolds/risers, and out the outdrive, no blockage there. Have ordered a new water pump. After that I'm out of ideas. Doesn't seem that much can go wrong with water pump other than impeller, but only thing left to replace so I thought I'd give that a try. It was at least 12 years old, don't know how long they should last. Am I on the right track? Where else should I be looking at? I believe I've covered the whole raw water cooling system. As far as I know, The thermostat doesn't have any effect on the raw water cooling system. Am I right about that? I do also have a closed fresh water system where I believe the thermostat comes into play. That system is working okay as far as I know. Desperate for advice, and as you can see I haven't spared any expense with new parts. Even if the parts I replaced weren't the problem, they were due to be replaced. Manifolds and risers didn't look too good so I'm glad I changed them. They also were at least 12 years old. How long should they last? I hope I've provided enough info for someone help me out with this problem. Missing the spring fishing season and desperate to get back out on the water. Of note, this all occurred after previous winterized condition when firing it up the first time to get ready for the season.
