Ran Engine Without Cooling

[openseas]

Hi all,
I have a 30" sailboat with a Yanmar 15hp. Today I ran the inboard motor for almost 6-10 minutes before I realized that I did't turn on the intake valve to cool off the engine.
As soon as I realized what happened, I turned off the engine immediately, then I turned on the intake valve, and I started the engine again, but this time I didn't see any water coming out from the side of the boat.
I am wondering if I ruined the water pump, and if so, is it a complicated job or not, and last, if the water pump needs to be replaced, does the boat have to be out of the water or not?

By the way, the engine didn't have any burning smell, and did't seize, and to me it sounds normal.
I dod't know much about mechanics, and I am happy that it happened in the marina and not in the open water.

I appreciate any advise from any of you out there.

Thanks

[Delancey]

I have to run my engine for 10 minutes from a cold start before the thermostat opens up, my guess is you are fine as far as not having overheated you engine goes. If you are not pumping water then maybe you trashed your impeller. Changing your impeller is not a big deal, you should have spares on hand for just such an occasion.

[S/V Illusion]

You will also need to find all the pieces of the blades you burned up to make sure they didn't get washed into the exchanger when you finally turned on the water.

[GILow]

And, depending on your setup, check that none of the exhaust system got too hot. I understand that some exhaust systems have plastic components that melt without the benefit of the cooling water flow.

[RaymondR]

If you trashed your impeller you may have been lucky it was so if your engine is raw water cooled.

One of the things you don't do with an overheated, raw water cooled engine is re-introduce cold sea water to the engine whilst it is still hot as this can cause extreme enough thermal shocks as to crack the block or head. This is not a problem if the engine has a heat exchanger as their are two water circuits and the cold sea water does not come into contact with hot engine parts. With a raw water cooled engine you should let the engine cool down before turning the sea water on and restarting the engine.

Check your exhaust system to make sure you have not melted a hole anywhere in it. After the cooling water is passed through the engine cooling system it is introduced into the exhaust system to cool the exhaust gasses. (Assumes you do not have a dry exhaust.)

[Neo]

Which yanmar engine do you have? I have the shop manual for the 2GM20F and 2GMF if you need it.

[roverhi]

Don't know if it's the same on the 2GM as the 3GM, but on the 3GM it's way easier to take off the pump to change the impellor than trying to do it with it in place on the engine. 10 minutes or less really shouldn't have burned the vanes on the pump impeller but I suppose it could have if you are not getting any water in the exhaust.

[kentobin]

2GM20(F)(C) Manual - downloadable pdf
http://www.yanmarmarine.co.uk/pdfs/s...al/EPB5494.pdf

[Cheechako]

replace your rubber impeller in the pump, make sure you get all the pieces. Everyone has done this once it seems! Early im sailing career I quit shutting the engine seacock. Heck the cockpit drain seacocks dont get shut.....

[Wrong]

You didn't say how long you ran the engine after opening the sea cock. If not long enough for your strainer, hoses and internal passage ways to fill, you wouldn't see water. I'd give it a try again, but check the strainer first to make sure it is full.

[GregSteimel]

I have a 2GM and replacing the impeller is a sinch: just pop off the cover and pull it out. Since you've never done this it's actually a good thing this happened. When you buy a Yanmar, the first thing you should do is replace the impeller. They're cheap and easy to swap out.

And you should definitely buy a couple of spares.

Also: I've made the same seacock mistake (more than once) with no ill effects. That engine is a rock.

[zeehag]

2 gm an d 3 gm use same shop manual as the 2 qm do--i have that manual on my ericson, which has a 2q series engine

[Wrong]

Originally Posted by GregSteimel

I have a 2GM and replacing the impeller is a sinch: just pop off the cover and pull it out. Since you've never done this it's actually a good thing this happened. When you buy a Yanmar, the first thing you should do is replace the impeller. They're cheap and easy to swap out.

And you should definitely buy a couple of spares.

Also: I've made the same seacock mistake (more than once) with no ill effects. That engine is a rock.

The engine may be a 2YM15, since the OP said it is a 15 horsepower. Still a rock. I've had the pump belt deteriorate quickly, leaving the engine with no raw water assist in cooling the engine - twice. Engine even heated up enough to cause the radiator cap to release ALL of the coolant from the exchanger. Shut down immediately when I saw the steam and probably before all the coolant had escaped.

Many hours later there is no apparent damage to the engine. Changing a belt is a PITA and they wear quickly. Alleged solution is to leave the belt 'loose'... Carry 3 or four spare belts. Available from Goodyear or Browning cheap. Belts | V-Belt, Light Duty 2L,3L,4L,5L | Light Duty V-Belts, 3L Series - GlobalIndustrial.com Don't remember the circumference of the belt, but if it's 12" you'll want a 3L120

[FSMike]

If you wish to continue closing your engine water intake tie the ignition key to the seacock when you do so. That will prevent any repeats.

[Wrong]

Originally Posted by FSMike

If you wish to continue closing your engine water intake tie the ignition key to the seacock when you do so. That will prevent any repeats.

Good idea, unless your old and forgetful.