Frozen engine - how bad?

[Poly]

I ran my engine (2str 20HP yam) very briefly this morning is a bucket of water, to check I had fixed a problem and that the battery still had enough juice to turn it over.

It was running only for about 30 sec-1 min so as to cause minimal disturbance to the neighbours. I planned to run it for longer to drain out the carbs, and basically winterise it later in the day when I had finished tidying up. So it didn't get hot enough for the thermostat to open.

I left the prob in the bucket during the day. Bad mistake. The water started to freeze by the time I got back to it. Now can't get engine to turnover. On turning the key the starter solenoid engages (click - and physically checked) but the motor doesn't spin. Pull start seemed very stiff so didn't persue this route as their seemed to be a problem. Battery is giving 12.6V at engine so don't think its as simple as that!

With kill cord pulled, and HT leads off - I can just turn the prop in gear by hand (not sure how far - seemed very stiff so stopped). It turns fine in neutral.

So - anyone experienced this sort of issue? Whats best way to go about investigating/fixing? I am guessing that the water in the leg has frozen and is stopping something turning. It was probably -4C today and it was in the shade; by the time I spotted it had frozen the bucket had about 2-3 mm of ice on the surface. Could it be as simple as the water in impellor/pump is frozen and it can't turn - so everything is "locked". Or would you expect the drive shaft to still turn - in which case has the ice bent something serious?

What is the best way to defrost this - very quickly (e.g. hair drier/heat gun), quickly (ie. inside boat shed with a heater close by) quite quickly (ie. just inside the boat shed asap), slowly (ie. leave it outside to warm up with the environment/weather) - bearing in mind that it may get colder before it gets warmer.

Are there any critical tests you would suggest doing before trying to fire her up after defrosting?

[codprawn]

Get it inside the house overnight!!!

Could be anything - could even be water in the gear oil has frozen. To be honest you shouldn't have tried to turn it over. Hope it's all ok.

[JSP]

At a guess it sounds like the gearbox oil has frozen like codders has already said. Not sure at what temp oil freezes though? Get in bed with it tonight and inform the wife there are three people in your relationship

[Chris]

I doubt that the oil in tgearbox has frozen, the impellor may have done however I cant see this causing too much of a problem just warm it up and try again.

I would not worry, these engines are designed to run in cold conditions.

[JSP]

According to the net (which is a source of info never to be questioned!!) Gear oil freezes at 0, 2 stroke at -25.

[Poly]

Originally Posted by Chris

I doubt that the oil in tgearbox has frozen, the impellor may have done however I cant see this causing too much of a problem just warm it up and try again.

I would not worry, these engines are designed to run in cold conditions.

I also doubt the gearbox oil has frozen as (1) the prop turns freely in neutral (2) it goes in and out of gear easily (3) the gearbox was below the level of the ice - so presumably was > 0 C anyway.

Will warm it up, investigate more and try again.

[mdt]

you should have stuck some salt in the bucket.

[Hightower]

My only guess is that as already mentioned it's the Impellor that has frozen, this is higher than the gearbox and possibly would have been pretty close to the frozen water line. This could be worrying because if the water in the water pump has frozen then you could do some damage to the impellor or the housing as some of these are plastic. Resist turning her over untill this has thawed out

My only suggestion is to keep fingers crossed, try and thaw the leg and try again.

[Poly]

Originally Posted by mdt

you should have stuck some salt in the bucket.

aye - bloody typical you normally go to great efforts to flush the engine to get rid of salt and then fresh water causes you the problem - salt would have been wise in the circumstances (or removing the leg from the bucket) - but I really didn't think it would freeze that quickly (and I actually expected it to get warmer throughout the day).

You live and learn - hopefully this will turn out to be a scare rather than an expensive learning curve.

[Poly]

Originally Posted by Hightower

My only guess is that as already mentioned it's the Impellor that has frozen, this is higher than the gearbox and possibly would have been pretty close to the frozen water line. This could be worrying because if the water in the water pump has frozen then you could do some damage to the impellor or the housing as some of these are plastic. Resist turning her over untill this has thawed out

My only suggestion is to keep fingers crossed, try and thaw the leg and try again.

thanks hightower. its due a new impellor at the start of next season anyway. So if there is any sign of a problem I'll drop the leg once its defrosted. hopefully if there is any damage it will be to something simple like the water pump / housing rather than something expensive like the drive shaft

[Nos4r2]

Can you get it indoors with the lower unit in a bucket of cold tap water to help defrost it?

[Poly]

Originally Posted by Nos4r2

Can you get it indoors with the lower unit in a bucket of cold tap water to help defrost it?

unfortunately not tonight. the engine is bolted to the transom, and by the time I de-rig steering, electrics, throttle cable etc the weather will probably be warming up. I will take it back to the boatshed at the marina tomorrow - and can certainly leave it in a bucket there - not sure how cold it will be as its not the most substantial building but it should be above zero. You said cold water - does that suggest doing it gradually is better than using warm water?

I could even leave it in warm salty water outside tonight (salty to stop it refreezing)?

[Nos4r2]

Originally Posted by Polwart

You said cold water - does that suggest doing it gradually is better than using warm water?

Yes-heating it rapidly isn't a good idea. It'll cause a sudden increase in pressure in any air in the gearbox for a start.Just the temp it comes out of the tap will be OK.

Originally Posted by Polwart

I could even leave it in warm salty water outside tonight (salty to stop it refreezing)?

That might be an idea-or add some antifreeze to the water instead would be better.

[jwalker]

It was -4 here today and it's -9 now. You'll likely be at similar temps. Bung some antifreeze into the water and put the engine back in up to it's neck, if you're worried about how to warm it up.

Edit: Ooops, sorry Nos, didn't notice you mentioned that.

[Nos4r2]

Originally Posted by jwalker

It was -4 here today and it's -9 now.

No prob
Jesus! -9!

Salt won't do the business then. Antifreeze is really the only option.

[Poly]

Originally Posted by jwalker

It was -4 here today and it's -9 now. You'll likely be at similar temps. Bung some antifreeze into the water and put the engine back in up to it's neck, if you're worried about how to warm it up.

thanks Jeff, only 0.5L of antifreeze here which is probably not enough to stop my 50L bucket from freezing, if it really is as cold as that. Likewise I would need much more salt than Mrs P keeps in the kitchen to prevent that much water freezing. So I will take it back to port edgar tomorrow and pick up 5L of antifreeze on the way and leave the leg in that all day tomorrow.

[jwalker]

Originally Posted by Polwart

... So I will take it back to port edgar tomorrow and pick up 5L of antifreeze on the way and leave the leg in that all day tomorrow.

If you're going to Port Edgar, can you not just put it back into the sea?

[Poly]

Originally Posted by jwalker

If you're going to Port Edgar, can you not just put it back into the sea?

JW - don't be coming out with common sense simple solutions like that - when clearly there is a distinct lack of intelligence at this end to have frozen it in the first place .

It seems to be a little milder today - the frost is clearing from the boat and I saw a drip come out the cooling water inlets earlier - so its going in the right direction. Hopefully a day in the shed at Port Edgar will be enough - if not it will go for a dip tonight...

[JSP]

Out of interest I searched again on the freezing point of gear oil (although the more knowledgeable here have already stated it wont be that.)
Another source says Hydraulic Oil, Gear Lube & Gear Oil freezes @ -10.
Now imagine you moor your boat up and leave the leg in the water, you bugger off to get the car and trailer and your delayed for a bit. The flowing water will be at a lower temp to standing water (correct me if I'm wrong on that) and your box freezes as bad as a nuns box.
Will have to think on next time to pull the motor out of the water.

[jwalker]

Originally Posted by JSP

...Another source says Hydraulic Oil, Gear Lube & Gear Oil freezes @ -10.

Nah. My Castrol data sheet for my gear oil states the pour point to be -36c. My Fuchs hydraulic oil pour point is -45c and -42c dependent on grade.