"Thanks, Graham, for your disc
"Thanks, Graham, for your discussion about how the different parts of the cooling system work together. That stuff is like gold to a newbie like me! Based on your discussion, I'm going to go on and rebuild the water pump in my 150 XR6. I've already replaced both thermostats, but haven't run the boat to see if that helped. It has a water pressure gauge, and it never gets above about 10 PSI, all the way to WOT. And sometimes it oscillates very rapidly between about 3 and 10 PSI at around 4000 RPM. So I'm thinking I need to go on to the pump rebuild. Thanks again, Graham"