Frozen engine - how bad?

[Polwart]

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.

[Polwart]

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.

[Polwart]

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.

[Polwart]

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