Overheating?
 

92 Fever, 502 mag w/oil cooler

Bought my boat two years ago. Previous owner had it to a motor/repair shop 4 times for overheating during the summer.
Last year it blew up. It's all rebuilt and back running. Still was getting too warm. Changed the recirc pump, seawater pump, and thermostat. Runs 130 at idle, but on long runs it keeps slowly going up until 170 and the alarm sounds. Oil temp never gets above 150, but Water pressure is reading about 2 psi max.

Any idea where to start? People I know are out of ideas so I'm reaching out.

Help!

Sea Strainer leaking sucking air? Fresh water flush kit sucking air?

No Sea strainer or fresh water flush kit.

Hose collapsing? Did you replace all hoses..

I had a '35 Lightning that would overheat the exhaust. On the hose would pump water fine and might go 50 miles sometimes then burn a hole in the rubber hoses on the exhaust. Changed everything - checked heads - checked block - after 1 year and the motor out 3 times, it turned out to be the plastic keeper on the hose that goes from the drive through the gimble. This piece was cracked and at speed it allowed the hose to collapse cutting off most of the water.

Check all of your coolers for pieces of impeller stuck in them and blockeg

I have run into this also with customers boats. When you have checked everything thats what it usually turns out to be. Good Luck

This is another off the wall thing that happend to me similar to your experience. On my engine it would run fine until it reached 3500RPM, anything over that it would over heat. Their was a surface scratch in the housing of the impeller housing that would cause the boat to overheat. It was just big enough to fit the tip of your fingernail in.

if you have the fresh water flush like me, i don't get water pressure in one engine until the speed of the boat forces it up over the valves on the top of the engine compartment. it just won't prime itself. makes me usually idle out of slip on one engine then start the other when out of no wake.

you need 15 lbs of water pressure.If the impeller in the lower unit is good . it will do that.. Have you ever put a new impeller in it. They can fry if you run it dry for 10 seconds... Try it on dry dock. On dry dock mine pulls like 2 pounds of pressure at idle but in the water it's 3 then on plane it's 15.. Very important to have 12-15 on plane ..If you have a good impeller than you should have either water pressure or a major leak. $ .02