Outboard Engines And Cold Weather Operation

[desmobob]

In the late fall here in upstate NY, we routinely deal with sub-freezing temperatures.  When I pull the boat out from a day of fishing this time of year, I tilt the outboard all the way down and let it drain while I'm putting away my gear, attaching the transom straps, etc.  When I'm ready to leave the launch, I tilt it back up and attach my transom saver.  The boat is parked at home in this condition.

 

Yesterday, I got to the launch after a 20* night.  I launched the boat and fired her up.  While I was arranging gear and letting the motor warm up, I started thinking something just didn't sound quite right.  It took a moment before I noticed what it was: there was no water squirting from the outboard's tell-tale hole!  I shut it down and tilted it up.  There were no weeds plugging the intakes and plenty of water drained out.

 

The motor is in its second year and has been faultless (Mercury 40HP Four-stroke EFI).  I lowered it back down and let it sit for a while, thinking the cold temperatures might have had something to do with it.  After a couple of minutes, I fired it up again.  There was a nice, strong stream of water this time.  Phew!  Apparently, the impeller wasn't damaged.  I think something up higher was plugged by ice, but the impeller was spinning in water, as normal.

 

I went fishing and enjoyed the day, but watched the motor carefully, worried I might have done some damage.  It was fine.  When I got back to the launch, I did the same lower-the-motor-and-let-it-drain thing, then tilted it up and attached the transom saver.  When I got home, I was curious about water still in the motor so I took off the transom saver and lowered it.  About a cup or more of water came out!

 

I consider myself lucky that the little freeze up I had didn't do any damage.   I'll be sure to keep the motor in the down position when I get home from late fall fishing trips!  Do you guys in the North do anything special or take any special precautions to deal with potential freeze-up between trips?

 

Tight lines,

Bob

 

 

[Ski213]

I'm not really very far north but it does get cold here. I usually tilt mine all the way down, then up, then back down letting it sit for a few in each position. When I get it home I'll do it again and park it all the way down.

[WIGuide]

When you started it up and water didn't come out, it's possible the engine was not warm enough for that to happen. Not due to residual water, but because of the thermostat. In water that's very cold and a cold motor, it'll have to run longer to open up. With bigger motors I haven't noticed much difference regardless of water temp, but with something as small as a 40 it might not open up as quickly. There is also the possibility that somehow some water froze in your tell-tale. When something like that happens, or it gets plugged, it does not mean that no water is circulating in your engine, but rather the little that comes out just can't escape there. 

 

As far as doing anything different when it's cold, I'll let it warm up longer before I take off. When I pull it out, I'll leave the motor tilted up when I pull it out of the water, and let it drain that way. When it's done, I'll trim it down and let it sit that way for a bit, and then trim it back up to put the transom saver on. 

[desmobob]

I'm not really very far north but it does get cold here. I usually tilt mine all the way down, then up, then back down letting it sit for a few in each position. When I get it home I'll do it again and park it all the way down.

 

I think I will adopt this procedure in the future!  Better safe than sorry!  I think the important part is to leave it down, long-term.

 

When you started it up and water didn't come out, it's possible the engine was not warm enough for that to happen. Not due to residual water, but because of the thermostat. In water that's very cold and a cold motor, it'll have to run longer to open up. With bigger motors I haven't noticed much difference regardless of water temp, but with something as small as a 40 it might not open up as quickly. There is also the possibility that somehow some water froze in your tell-tale. When something like that happens, or it gets plugged, it does not mean that no water is circulating in your engine, but rather the little that comes out just can't escape there. 

 

As far as doing anything different when it's cold, I'll let it warm up longer before I take off. When I pull it out, I'll leave the motor tilted up when I pull it out of the water, and let it drain that way. When it's done, I'll trim it down and let it sit that way for a bit, and then trim it back up to put the transom saver on. 

 

If the water pump is working, water squirts from the tell-tale at all times, whether or not the thermostat is open yet.  Think about it... if it didn't, you'd never see any water coming from it until your engine was warmed up enough for the thermostat to open.  

 

But, it seems that it might not be unusual for the tell-tale circuit to freeze up...  From the Alaska Native Knowledge Network:

 

On the side of most motors there is a small hole that emits a stream of water. This is only an indicator that the water pump is working. Most of the water that comes from the cylinders is exhausted through the lower unit. During cold weather, the indicator might freeze even though the pump is working well.

 

Tight lines,

Bob

[Nick B]

I always trim my outboard all the way down when I park it year round. This allows for draining not only of water, but also of any petroleum products that could get into the impeller. I had an outboard that I didn't trim all the way down and some oil and gas got into the impeller and destroyed it prematurely.

[WIGuide]

If the water pump is working, water squirts from the tell-tale at all times, whether or not the thermostat is open yet.  Think about it... if it didn't, you'd never see any water coming from it until your engine was warmed up enough for the thermostat to open.  

Not the case on all motors. My friend has a 50 hp Mercury who had a small piece of debris that got wedged in the spring on his thermostat which prevented it from opening and no water was coming from his tell tale. Once the piece was removed, everything worked properly again. 

[desmobob]

Not the case on all motors. My friend has a 50 hp Mercury who had a small piece of debris that got wedged in the spring on his thermostat which prevented it from opening and no water was coming from his tell tale. Once the piece was removed, everything worked properly again. 

 

You're right.  I did a bunch of reading on the subject and it seems there are a few engines that have the tell-tale circuit downstream of the thermostat.  Mine is upstream and has always shown water immediately on starting.

 

Tight lines,

Bob

[Smokinal]

I do the exact same procedure as you Desmobob, but I store my boat with it down in the garage and, you are right, I do get a little more out of it when I lower it again at home.

[tander]

I always store my motor down reguardless of time of year. I also lower it on  4x4 piece of wood black so no strain is on the tilt. I not saying that this is the correct procedure but this is just what I do. When I lower it at home, water always runs of of it.

[Robeng]

I have a 1991 Mercury 40 HP - 2stroke - 4 cylinder that is oil injected. I live in Michigan. At end of season i leave it down parked in garage. I do lower unit oil change and pump glycol propylene antifreeze thru engine. Fog cylinders. Done. Always tilt it down for storage. Also good idea to come home and flush engine with water after each trip in warm weather season.

[BaitMonkey1984]

I just keep the motor tilted all the way down. Also, my driveway has a slight incline so if it is really cold I would pull in truck first letting the motor sit a decline, to make sure every drop is out of that outward. I usually keep the transom saver on the boat all summer. So remember to do a walk around and put the motor up before taking off for a day on the water. I got about 20 feet down my driveway before I realized that strange noise was my keg scraping the driveway. 

[Catch 22]

I have a Yammie 115 with the pee tube that comes from the upper port side.  It had a small saddle that allowed water to remain and thus would not evacuate totally even with engine down.I shortened it enough to have a sweeping bend to completely drain . No more freezing probs.

 

Heres a thought. For those able to drain more water at home as mentioned,  could that be condensation that formed on the way home.=warm engine ===cold air?

 

C22

[Skunked again]

I do the same as ski213. Never had a problem. Leave engine in down position at home also.

If your not going to use the boat through the winter, drain lower unit fluid, and replace. This will also let you know if you have a leak, and if you do, you have all winter to fix it. One less thing to do in the spring.

[Team9nine]

The one thing I haven't seen mentioned that I always do. After trimming the engine all the way down and letting the water drain out (after coming off the water), I always flip/pull the kill switch and then try and turn the engine over a few short times to allow the lines to completely be expelled of water. It's likely where the "extra" water is coming from that doesn't drain off quickly on its own. Just be sure to remember and hook the kill switch back up after doing this.

 

-T9

[WRB]

You can start the engine out of the water with it tilted down for 10 seconds or so to purge out the water, will not damage anything, it runs dry every time you start it until it warms up.

The pee stream only indicates the water pump is working, look at the exhaust to determine power head thermostat is open allowing water flow or get a water pressure gauge for the power head; 10-15 psi is normal idling pressure.

Tom