Draining the cooling system

[Davey]

I was just wondering whether you guys use the hoses beside the engine to drain the cooling water out of the block & exhaust manifold after each use? Our boat is operated in salt water so I flush the motor every time with fresh water as advised in the manual but do not drain the cooling water.

Trouble is when we got home & parked the boat in the garage after our last outing I noticed the exhaust outlet down near the leg has dry rust marks around it like it has been blowing out rusty water & the thermostat appeared to be stuck open, engine was not heating up while we were out on the water. Sounds like the cooling system has rust in it & the thermostat might have seized. The Mercury manual says to only drain the system for extended storage or if freezing temps are expected. It was only about 4 weeks between outings.

Going to book it in to get checked out but just wondering what you guys normally do?

 

[jhild]

Since you are already flushing out all the saltwater, there is no reason to drain the system each time you use the boat.

 

[Davey]

Thanks for responding, the workshop also confirmed no need to drain after each use. Boat is booked in to get the thermostat checked tomorrow.