Maybe someone can send me in the right direction here. we were out in my 25ol. I went to go into a swimming area, I felt the lower snag a bit in the sand. Was going at idle. I backed out. n we left. After a few hundred feet I saw my gauge reading above 180. It always sat right below 180. If I went to go faster the temp would rise very slow but steady. If I went at a fast idle back to the dock it was around 180 + or - a bit. anyway... I pulled the lower off. repaired the nick. I then pulled the seawater pump and the impeller looked fine. I had a new one to put in but I didn't cause the one in there looked the same. I back flushed the hose from the pump to the lower. all seemed fine. water seems to shoot out the pipes about the same. but temp still goes abit above 180 on the hose. The port manifold feels slightly hotter to touch on the top. We read the thermostat housing area with a thermal gun. it showed 140 when the gauge said 180ish...? I don't want to take it out again till I have this resolved. any thoughts?? btw its a 502mpi. before I bought it. It was overheated. has about 30hrs on new longblock and 237 on the rest....thoughts? Thx

You may have plugged up part of the block with sand. Did you pull all of the drain plugs and flush?
Also, did you check the SWP housing? Is it all scratched and scored up? This will cause reduced flow and cooling.

Anytime you pull the SWP off, put a new impeller in there. It's cheap insurance.

I agree with above.....impeller housing if scored or grooved will cause motor to run hot. Had this happen to me last month....impeller was intact but housing was scored up and motor got hot. Replaced both and back-flushed hoses...all good now.

Had the same thing happening to me for the last two seasons. Started last year, would run fine at low speed but as speed would increase temp would also. I changed , manifolds, risers, impeller, temp sensor, gauge,cleaned power steering cooler, flushed hoses and still the same thing. Last week just for ****s and giggles I changed the thermostat. Problem solved. VERY EXPENSIVE THERMOSTAT. Start there.

I must be the luckyest SOB in the world. I kick sand up all the time. I can't even get out the channel without kicking some up. When we go to the beach I kick up sand. I never have a problem with this. Christ I even got myself really stuck the weekend before last, had to have everybody get in the nose of the boat to get out, still no problem.

Lucky man,for some reason always have to change something. BOAT.( BRING OUT ANOTHER THOUSAND )

Does your drive have a low water pickup?

yes mine does.

Those are bad news. With the drive up it puts the water intake right on the bottom where it sucks up sand like a vacuum cleaner when you are in shallow water. Do everything you can to get the sand out of the block or you will cook your engine. You may need to pull the exhaust manifolds and then take the freeze plugs out of the block so you can get all of the sand out. It is a lot of work but it can save your engine. Good luck.

ya it seems odd that the port side riser is warmer. I feel like theres something in there slowing flow to that side. in the driveway at 2k the water shooting out seems equal, but im sure that isn't a good test?? my mechanic told me the thermostat is off, because it was showing 180 and the thermal gun showed 140... thoughts?