Winterisation Advice Sought

[A_Sails_Pace]

I’m preparing for a few months in the yard to do a few jobs and am potentially planning for an early launch next year (famous last words, I know).

I’ll have electric hook up, and based on a wide variety of advice I’m also planning to leave a low power tube heater on board whilst I regularly come back and forth.

I was wondering though, whether or not it’s best to just service my Bukh 20 and allow the heater to keep any freezing at bay, or whether a full winterisation is best? As it stands I’m already planning on keeping the batteries connected as I have a 100w solar panel and I’m thinking that keeping it topped up this way (albeit with less sunlight) may be a satisfactory idea.

Thoughts appreciated? I’m just not totally sure. I was just thinking that I’d crack on with a decent service and prevent freezing or harsh temperatures for the few months we’re out?

 

[Tranona]

If your engine is freshwater cooled then it will be full of antifreeze, Just drain the seawater side. If you are running a tube heater all the time (or even on a timer) highly unlikely the temperature inside the boat will ever get down to zero, even if the outside does.

 

[dunedin]

If your engine is freshwater cooled then it will be full of antifreeze, Just drain the seawater side. If you are running a tube heater all the time (or even on a timer) highly unlikely the temperature inside the boat will ever get down to zero, even if the outside does.

I tend to keep the boat afloat, so rarely do this, but I had always thought you should run fresh water plus antifreeze into the ”seawater side” to prevent corrosion as a well as prevent freezing.
Would simply draining the sea water side lead to corrosion ? And what is the easiest way to drain fully?

 

[Tranona]

Close the inlet with the engine still running to expel as much water from the exhaust. Shut the engine down and remove the impeller. Corrosion is not an issue with a freshwater cooled engine as the seawater is only in the pipes (mostly rubber) and the exhaust water trap, which usually can be drained if you don't manage to expel the water as described. with a seawater cooled engine there is a case for filling with antifreeze, but corrosion is not really a big issue compared to the effects of running hot seawater through the cooling passages in normal use.

 

[vyv_cox]

I assume your Bukh is raw water cooled? To flush with fresh water is difficult as the thermostat needs to be open. One possible is to remove the thermostat and pinch the bypass hose with a mole wrench, run the engine while taking the pump feed from a bucket in the cockpit topped up with a hose. Then drain the block via the drain valves and remove the impeller. You could finish off the flush with a can of antifreeze, or even circulate by catching the water plus antifreeze emerging from the exhaust, but water in a warm block will evaporate quickly.

 

[A_Sails_Pace]

Thanks for the advice above. Yes, we’re raw water cooled. We’re already out of the water and I’ve drained what I can just by simply opening the outlet. Issue being, as mentioned in some comments above, is that there’s likely an amount of raw water still in the system.

 

[Spirit (of Glenans)]

Thanks for the advice above. Yes, we’re raw water cooled. We’re already out of the water and I’ve drained what I can just by simply opening the outlet. Issue being, as mentioned in some comments above, is that there’s likely an amount of raw water still in the system.
There should be a drain outlet on the block to drain the galleries within. I don't know the particular engine, my experience being confined to a Beta and a Volvo Penta, but I should think that simply opening the outlet might not allow all the water to escape. Your manual might reveal this.

 

[Spirit (of Glenans)]

Thanks for the advice above. Yes, we’re raw water cooled. We’re already out of the water and I’ve drained what I can just by simply opening the outlet. Issue being, as mentioned in some comments above, is that there’s likely an amount of raw water still in the system..

There should be a drain outlet on the block to drain the galleries within. I don't know thelayout of the Bukh engine, my experience being confined to a Beta and a Volvo Penta, but I should think that simply opening the outlet might not allow all the water to escape. If you have a manual it might be shown in an exploded diagram.

 

[neil_s]

On the DV20, the drain plug is next to the oil filter, towards the gearbox.