how deep is the water under your boat? when you put it in the water you might be in shallow water and sucking up sand or when you pull the boat off and start moving it may be shallow check it out Greg

No sand anywhere near his slip. Rocks...........and BIGGER rocks!

I pulled the starboard impeller. It's fine. The hoses were full of water. I now suspect the thermostat.

I checked the water level. The seawater pumps are defintely below the water level. However, the water does not "rush" in when I disconnect the inlet hoses.

I may have more than one problem.

I'm still working in it...

? for ya. Before you had this problem what were the water temps and psi at that point compared to now?

The engine temps run steady at 150. The PSI varies depending on the engine RPMS.

I have the "original" thermostats that came with the boat in 2006, so I don't know how old they are. I think that the starboard thermostat was stickng and caused the engine to get hot. I shut it down at 180.

This has not been a major problem, just an annoyance.

I would compare the flow of water from each side of the sea water intake hose. While on the trailer & the boat submerged pull each hose off individually & take note of the differerance. More than likely the side that is normal will fire hose psi just as if you had a hole in the boat. And/or remove the hose fitting at the the gimbal (boat out of the water) and compare the differerance. If that hose retainer is not perfectly round you have found your problem. If they both are the same try backwashing the problem side. You may have a clog from the drive pickup to the gimbal. Or a clog in the oil cooler. Its a process of elimination.

well... I backflushed everything I could find, reconnected all the lines, and took the boat for a run.

Everything is working perfectly now.

Thanks for all your input!

Clay if you want to try a set of Run Dry impellers let me know I have 2 w/ less than 10hrs on them.

Michael