Engine was running a tad high (190), so i figured it was time to check the impeller in the RWP. Replaced it, even though the old one looked fine. Pulled and tested the thermostat, seemed to be ok. Problem got much worse, now the engine overheats completly. After replacing risers and manifolds, inspected a perfectly clean heat exchanger. Still have an overheating problem. There is a water circulation problem obviously, but it seems that the raw water pump is simply not working at all now. The risers heat up as soon as the engine turns on which means to me, no water is getting there at all. Any trouble shooting ideas on the rwp, i have also read other posts on cracked tubes and connections where the water comes through the outdrive....but the problem is not getting enough water, the problem is not getting any water to the raw water pump. I have been able to get it primed and running with a garden hose by backwashing the system at the raw water pump, while in the water....but once the boat comes out of the water and back in, it loses a prime at the pump...so it seems that the raw water pump is simply not getting the job done on its own. Any ideas or similar problems???
