My starboard engine is running 30 degree's warmer than port--have replaced thermostat and sender, cleaned heat exchanger, oil coolers etc etc

At point of questioning the circulating pump. Is there an easy way to verify that it's working or not without removing from engine???

Poorsche

www.boatmat.com

have you put your hand on the riser or other to verify it's not just the sender/gauge. Circ pumps don't really stop working unless the seal goes then it will run out the bottom of the pump. It's one piece from the pulley to the impeller.

Probably should have stated that engines have Closed Cooling system--water thru risers would be raw (sea water). THe coolant in engines is 50/50 antifreeze water mix.

Poorsche

Still,feel a hose that recircs,, and it can't really stop working unless the seal blows or the belt is off,,then you'd know it.

Tempest,just because the guy didn't find the problem yet doesn't mean he's a IDIOT!What if his boat does'nt have a strainer or a thermostat,mine doesn't,Please tell us what then TEMPEST of knowledge!

For the record -- when engines were out of boat we did clean out the strainers, coolers, flushed cooling system. Thermostat and sender was replace when proble kicked in before engines came out. Also rerouted plumbing, re-did the pickups from transom to thru-hull and took the heat exchanger off and flushed it and de-scaled.

Would a defective radiator cap contribute to problem?

Today I'm going to check wiring at gauge for voltage, switch guages from eninge to engine and see if problem follows wiring or is constant, check for good ground, check sender, and see what the RINDA engine analyzer says.

Damn I don't wnat to try and replace circulating pump with enigne in boat and I don't want to pull engine again.

Any tips to solve this mess sure would be helpful--

thanks--

Tempest, the grown ups are talking - now go outside and play with yourself.

I know a guy who had a similar problem with t575s. One motor ram hotter than the other. He took the water pump off the suspect enging and pulled the cover off the back. I don't remember exactly what he said was wrong with it, but the impeller was messed up. New water pump cured the problem.

Tempest, what I meant was feel a hose or jacket at the same place on both motors to verify the 40 deg diff. the gauge is showing.Real simple test . I'm not familiar with new closed cooling systems ,and they may have an elec pump, but if it's the standard circ pump as in every American V8 for the last 50 yrs,,,The impeller and shaft are basically one piece and don't go bad,only the bearing and seals, then it blows antifreeze out the bottom.
Tempest,what's a termostate anyway?
Tempest,I do feel like bit of an idiot for arguing with you , but it's so easy

Cooltoys,

Being an auto mech, I have seen the impeller go bad on cars before. Car water pumps, the impeller is steel, and boat are bronze I think because of river/lake and salt water in fresh water systems. I have seen steel car impellers eaten away with corrosion before where there were no blades left. With a closed cooling system, could he have a water pump with a steel impeller that has corroded away?

I'm having similar issues with my motor but don't want to pull the pump. Pain in the azz, back seat has to come out.