Yanmar 2qm20h overheating warning light keeps coming on

[Mike Buckley]

I have a problem with my yanmar 2qm20h engine. It appears to be overheating and the warning light comes on after about 30 mins run time. I've replaced the thermostat, checked the impeller and most of the hoses for blockage. In the past I've regularly replaced two of the three anti corrosion anodes but can't change the one nearest the water pump as the nut is stuck solid. Wondering if the overheating problem is in this area?

 

[SeasickPete]

Is the engine actually overheating or may it just be a faulty temperature switch?

Is plenty of water coming out of the exhaust? Check for inlet strainer and try to back flush with a hose from the dock to clear a possible blockage on the inlet side. Maybe even take a long stiff metal wire and poke that down the strainer inlet to the seacock.

 

[Mike Buckley]

Is the engine actually overheating or may it just be a faulty temperature switch?

Is plenty of water coming out of the exhaust? Check for inlet strainer and try to back flush with a hose from the dock to clear a possible blockage on the inlet side. Maybe even take a long stiff metal wire and poke that down the strainer inlet to the seacock.

Thanks Pete, yes the engine does appear to overheat. You take onboard your sound advice and try to backflush and have a poke down the strainer. Thanks for your advice.