1.7 Merc diesel overheating

[big_si]

The surveyor picked up the fact that our engine overheats when on FOT.

Now I think I remember hearing somewhere that occasionally petrol thermostats end up being fitted so the engine always looks hot on the gauge.

Has anyone else had overheating issues on their 1.7 Merc?

Also I have heard that a flush through with acid (!?!) could clear any nasties?

Thanks heaps.

 

[tinkicker0]

When was the last time you changed the impeller and cleaned out the heat exchanger?

 

[big_si]

not sure about the heat exchanger, but the impeller was changed a few months ago.

Yesterday was the first time it has been in the water since the service!!

 

[PetiteFleur]

Check the heat exchanger - I had overheating problems if run at more than 2500rpm this summer so last week had the end caps off the heat exchanger and about half the tubes were blocked with deposits and bits of impellor rubber! Cleaned it all up and today went for a run up river. No overheating, flatout(3200rpm) for ½ hour, gauge just stayed on 75/80ºC. Problem solved. Engine was a Beta 25HP, 4 years old.