Winterising raw water cooled engines

[JumbleDuck]

So I got a bucket of water next to engine, ran the engine for 5 minutes on idle, and repeated 4 times. Wouldn't heat up so I aborted!!

Mine takes absolutely ages to warm up when idling ... there just isn't that much heat around. The ten minute trip from my mooring to the lift-out place in the marina next door is just about enough, so I normally winterise there immediately before the crane does its stuff.

 

[roblpm]

Mine takes absolutely ages to warm up when idling ... there just isn't that much heat around. The ten minute trip from my mooring to the lift-out place in the marina next door is just about enough, so I normally winterise there immediately before the crane does its stuff.

Too late. Mine is out!!

 

[ripvan1]

It's basically pointless and potentially harmful. Running engines from cold under low load is bad for them for all sorts of reasons, including bore glazing, high wear rates and acidic corrosion. The latter may be less of a problem now that sulphur in fuel is so much reduced but the combustion process still produces plenty of other organic acids that accumulate in the bores and oil. Best advice is to leave the engine alone until spring time. It will come to no harm whatsoever.

Thanks for that v-c, I'm in process of installing replacement engine, am out to the boat regularly and tend to start engine and put in gear at low throttle. As I intend to go out over winter months (if the sun ever shines again) I feel that sarting up every now and then can't do much harm and would help keep the rust at bay.

As Vic S said - "The trouble with draining the engine is that you probably cannot drain it completely. You leave it wet, salty if not well flushed, and full of air anyway which is a bad combination from the corrosion point of view."

Comments welcome

 

[Scotty_Tradewind]

As I intend to go out over winter months (if the sun ever shines again) I feel that sarting up every now and then can't do much harm and would help keep the rust at bay.

[/I]."

Comments welcome

imho.....
That's a good idea if you put it in gear and give it a little work to do it will warm and dry the boat etc... and put back some battery charge.

S.

 

[roblpm]

Mine takes absolutely ages to warm up when idling ... there just isn't that much heat around. The ten minute trip from my mooring to the lift-out place in the marina next door is just about enough, so I normally winterise there immediately before the crane does its stuff.

............. and this would have been so easy! As I have to move my boat to a waiting pontoon for the crane. Warmed up engine, bucket ready with water antifreeze mix. Whip the inlet hose off, run the bucket w/antifreeze through. Lift out. Drain engine. Bingo!

 

[eddystone]

I don't blame you. I guess the most economical/elegant way to do the necessary won't always be the same for everyone*.

The water pump change, is this because it is leaking or lacks suction? A good reason to do it/get it done at the same time as the winterisation, which could otherwise be a bit trickier...

because, if it is dodgy suction-wise, it won't be self-priming, and probably won't suck up the water/coolant mix from the strainer box.

BTW, if you do siphon, make sure the siphon hose is full of water, then put one end into the bucket and your thumb over the other end to stop it draining out until it's in the place you want it, which must be below the water level in the bucket.

*My own preferred technique (a bucket outside the boat with a hose from it jammed into the engine inlet skin fitting) involves the least (ie nil) dismantling of engine/cooling system bits, and no clearing up inside the boat either. But I do this when ashore.

I know the raw water pump needs replacing or at least needs new seals because there is a steady, now quite fast drip from the slot in the section between the pump and the impeller housing.
Winterising while waiting for lift out - wow I wish I had that much mechanical confidence - all my attention will be devoted to getting lines sorted to effect a rotation into the required position.

As I have to get someone to sort out the water pump they can do the winterisation at the same time - not very PBO I know!

(However if I had to do it myself I would go for the hose in a bucket method but would need tap on end of hose to control flow; sticking a hose up through the engine seacock not a good idea I guess)

 

[vyv_cox]

sticking a hose up through the engine seacock not a good idea I guess)

Definitely to be avoided. A hose with decent pressure will easily push water past the blades of an impeller. When the engine is not running this water will be filling first the trap, then the manifold, then perhaps the engine via an open exhaust valve. Starting the engine will try to compress the incompressible, with catastrophic results.

 

[eddystone]

Definitely to be avoided. A hose with decent pressure will easily push water past the blades of an impeller. When the engine is not running this water will be filling first the trap, then the manifold, then perhaps the engine via an open exhaust valve. Starting the engine will try to compress the incompressible, with catastrophic results.

Cripes!

 

[roblpm]

Well just finally did mine today after I managed to sort the problem with the marina hose (user error, I was trying to open the stopcock anticlockwise!). Anyway ran the engine for about an hour! Still not convinced it was warm though! Maybe the exhaust water never gets hot?! It was definitely warmer than the cold water i was putting in so i will hope for the best. Ran the prop as well as it has a deep sea water stern gland so I think its ok to run it out of the water, was plenty of water coming out of there.

Next year I will do it with one bucket of fresh water amd antifreeze just before haul out!!

 

[wombat88]

I don't know if anyone has mentioned it but I was taught that it is good practice to remove the fan belt and lightly grease the pulleys so that they do not rust. Clean them when re-commissioning and you will prevent a build up of rust abrading the belts and reducing their lifespan.

 

[eddystone]

Interestingly, the engineer who removed my water pump for inspection winterised it first by simply closing the sea cock, taking the top off the strainer, started the engine and then poured anti-freeze into the strainer, turned it off after judged sufficient gone through the system. The boat was in the cradle maybe an hour after lift out but still warm.

 

[lw395]

I don't know if anyone has mentioned it but I was taught that it is good practice to remove the fan belt and lightly grease the pulleys so that they do not rust. Clean them when re-commissioning and you will prevent a build up of rust abrading the belts and reducing their lifespan.

Or wrap the pulleys with insulting tape.

 

[eddystone]

Or wrap the pulleys with insulting tape.

You might regret that later

 

[vyv_cox]

Interestingly, the engineer who removed my water pump for inspection winterised it first by simply closing the sea cock, taking the top off the strainer, started the engine and then poured anti-freeze into the strainer, turned it off after judged sufficient gone through the system. The boat was in the cradle maybe an hour after lift out but still warm.

Well, that's the bypass corrosion and freeze protected then!

 

[bluerm166]

Well as the thread is still running here's a gash Yanmar thermostat held open so as to flush the galleries with antifreeze rather than simply the bypass.Useful if its difficult to get to temperature.
https://picasaweb.google.com/lh/photo/shfZI59BTCjhoZajYKtdia0M1PHVJRBuP6yjbOngLFQ?feat=directlink

 

[Scotty_Tradewind]

Well, that's the bypass corrosion and freeze protected then!

My understanding of all this is still 'wishy washy'.

Yes on land difficult to get to temperature to do more.

Would it help to syphon header tanks of old antifreeze and then refill or would this still not get to all parts?

S.

 

[vyv_cox]

My understanding of all this is still 'wishy washy'.

Yes on land difficult to get to temperature to do more.

Would it help to syphon header tanks of old antifreeze and then refill or would this still not get to all parts?

S.

Are you confusing raw water and indirectly cooled engines? Raw water cooled ones don't have header tanks, seawater passes through the bypass until the thermostat opens, when it is directed through the engine. A 'warm' engine will not have an open thermostat, it opens at around 60+ degrees.

In an indirectly cooled engine the water plus antifreeze only needs to circulate for a minute or so to be completely mixed. It is possible to do this on land with no additional cooling but there is a risk that plastic parts in the exhaust system might suffer. Best way is to take a length of plastic tube from the seawater pump inlet to a bucket in the cockpit, fill the bucket with fresh water, leave the fresh water hose running and flush the seawater side. What I do is use my Vetus strainer as the bucket, simply keep it filled while the engine is running with a pistol tap on the hose. Or even have about five gallons of water in a plastic container, pour it in with the engine running until all gone, then shut down. That is in Greece where it doesn't freeze in winter. In northern Europe I would drain the pump and exhaust trap.

 

[Scotty_Tradewind]

Are you confusing raw water and indirectly cooled engines? Raw water cooled ones don't have header tanks, seawater passes through the bypass until the thermostat opens, when it is directed through the engine. A 'warm' engine will not have an open thermostat, it opens at around 60+ degrees.

In an indirectly cooled engine the water plus antifreeze only needs to circulate for a minute or so to be completely mixed. It is possible to do this on land with no additional cooling but there is a risk that plastic parts in the exhaust system might suffer. Best way is to take a length of plastic tube from the seawater pump inlet to a bucket in the cockpit, fill the bucket with fresh water, leave the fresh water hose running and flush the seawater side. What I do is use my Vetus strainer as the bucket, simply keep it filled while the engine is running with a pistol tap on the hose. Or even have about five gallons of water in a plastic container, pour it in with the engine running until all gone, then shut down. That is in Greece where it doesn't freeze in winter. In northern Europe I would drain the pump and exhaust trap.

thanks Vyv.... is it therefore o.k. to run the engine for an indirectly cooled engine, flushing the raw side of things with antifreeze then empty header tank of water/antifreeze then refill with fresh antifreeze to level?

S.

 

[eddystone]

Well, that's the bypass corrosion and freeze protected then!

Suppose I could take the thermostat out and repeat the process.

 

[vyv_cox]

V

thanks Vyv.... is it therefore o.k. to run the engine for an indirectly cooled engine, flushing the raw side of things with antifreeze then empty header tank of water/antifreeze then refill with fresh antifreeze to level?

S.

Not quite sure what you are trying to achieve here, Scotty. I would treat the coolant side first, change antifreeze, top it up, whatever, then do the seawater side. In most cases I see little benefit in putting antifreeze into the seawater side, I would prefer to drain it. If there is a significant ferrous content to the heat exchanger it might benefit from the corrosion inhibitor but in most modern engines there is nothing in there to corrode. IIRC you have a Bukh? In which case it could be useful but for my Yanmar there is only rubber, plastic and stainless steel in the seawater system, so no advantages.