Morning i have a 1975 campion boat with a ford 289 and it overheats when under load. The thermostat is not in the block it is iine from the heat exchanger to the hoses. One going to water pump.i dont think this is right.
I havent seen thos configuration anywere. I dont beleive it is normal. I havent changed impeller yet i just got the boat. I have changed water pump, replaced end gaskets on heat exchanger, manifold elbow gaskets
It appears that you have a Mercruiser , if not post a picture of the drive. I recognized the Holley distributor. I only have seen them on Ford/Mercruiser 302 models.
I am getting air in the system and can't figure out why..I've changed hoses..clamps...water pump...impeller..ect..my fluid fills overflow and leaks it out top...however it isn't really hot....it will not drain back into heat exchanger...help
With the overflow filling I wonder if you have a blown head gasket
Post some pics of the motor hose routing to help me understand how its connected. I'm looking at manual 2 and want to compare
It is possible that a blown or leaky HG is putting hot exhaust gas into the cooling water. You could get one of those carbon monoxide test kits to see if that’s the case; easier to determine with the closed system. We had a similar problem on a 98 Subaru EJ2.5 flat 4, these are known for blowing HGs. Symptoms were episodic overheating and bubbles/black residue in the recovery tank.
The HE doesn't look like the typical Merc design. The older design used 2 hoses coming in from the Thermostat housing to the front of the mans and 2 others coming back from the rear of the mans. I'm seeing what appears to be 3 hoses (maybe more) connecting to the top tank
Thermostat has 2 coming out wich run to the bottom and back of exhaust manifold..that odd connection with 3 has 2 going to front of exhaust manifold and onesmaller one to water pump..and the main water.pump hose goes to bottom of heat.
The one coming from (flow toward) the water pump should go to the thermostat. If it did go to the water pump this would help flow into the block. With it going toward the mans reduces the flow into the block.