Over heating D2 55 sero

[Mervnjudy]

I’m experiencing engine over heating when the revs go over 2000 We’ve cleaned the heat exchanger but it’s still doing it. We’ve also replaced the thermostat and the impeller and the raw water filter is in good condition and kept clean. Also no blockages in the sail drive. The exhaust elbow has been cleaned. Any suggested?

[IslandAlchemy]

Exhaust elbow?

[sy_Anniina]

Do you get enough water from saildrive leg - barnacle growth?

Have you inspected impeller?

Is the raw water strainer leaking air into water flow - (I had this issue once)

BR,

Tommi
s/y Anniina

[IslandAlchemy]

Yes, I forgot about the saildrive leg blocking. Very common problem.

[MagicalArmchair]

The previous owner of Mirage had overheating problems due to growth in the sail leg. The cooling water now comes from two seacocks, with a y piece joining them up before heading to the strainer.

[allendick]

If there are any air leaks on the intake to the raw water pump, volume will be reduced.  If the leak is above the waterline, no water will show to indicate the location, but air will get in and it does not take much air to reduce the flow.
I once had a raw water pump that leaked air on the suction side.  That leak was not obvious and gave little in the way of clues as we normally look for water tracks or drips.  Loose clamps on the intake hose can let air in without leaking water.  A tricky one I had once was dirt on the lid gasket on the strainer.  Careful cleaning and a little Vaseline fixed that.