Question regarding below freezing operation

[woody1]

Is there anything I need to do differently when running my outboard at below freezing temps? Any difference if running 2 or 4 stroke? I have both but have never operated them in really cold weather. Thanks and regards, Woody

 

[1960 yellowboat]

I had a 7.5 merc that was out in the cold and the water in the impeller housing froze unbeknown to me. when I next started the motor, the impellor disintergrated and steam came out the pee whole.

 

[lckstckn2smknbrls]

I was a duck hunter and used my boat in freezing weather all the time. Make sure the lower unit doesn't have any water in it. When on the water leave the motor down. When loading your boat onto the trailer leave the motor down to drain all the water before heading home.

 

[DaleH]

I was a duck hunter and used my boat in freezing weather all the time. Make sure the lower unit doesn't have any water in it. When on the water leave the motor down. When loading your boat onto the trailer leave the motor down to drain all the water before heading home.

Ditto, everything I was going to say! Also FILE a float plan, as there's no 2nd chance in those temps! Came back in once and my right arm of the jacket (hand on the throttle on the starboard funnel) was entirely encased in ice! Ran in against spray over the starboard funnel. I could my fingers OK, but could not move the arm at all ...

Be SAFE!

 

[woody1]

Thanks for the insights. I've always made sure the lower unit was drained prior to storage as the motors are always stored outside and I live where the winter temps are a little chilly. So need to do same when pulling out of the water in freezing temps I get that. Just wondered if there was anything else. Regards, Woody

 

[onthewater102]

I think he meant not to tilt the motor up while you're out on the water - not just once you get the boat back on the trailer. Even while you're bobbing along on the water if you've got the motor tilted up you could get icing around the impeller if you have the lower unit tilted up out of the water.

When I'm out in the cold in fresh water I'm fishing deep structures so scraping the skeg isn't an issue and I don't ever tilt the motor up.

 

[lckstckn2smknbrls]

I think he meant not to tilt the motor up while you're out on the water - not just once you get the boat back on the trailer. Even while you're bobbing along on the water if you've got the motor tilted up you could get icing around the impeller if you have the lower unit tilted up out of the water.

When I'm out in the cold in fresh water I'm fishing deep structures so scraping the skeg isn't an issue and I don't ever tilt the motor up.

You are correct,
The water is warmer than the air, if you tilt the motor up the water that is trapped in the motor will freeze.

 

[MrGiggles]

I know first hand that a motor will freeze if you do not trim it fully down after pulling it out of the water. Froze mine up solid last year when I forgot to pull the transom saver and let it down when I got home. It's especially true if you have a low trailer and the transom saver has the motor sitting pretty high like mine.

If you leave it in the water, leave it trimmed down, do not pick the motor up as it will not likely drain all the way. If you pull the boat out, raise the motor all the way up first, and then leave it down so it drains fully.

As for the motor itself, I have not had any issues. Most have thermostats to regulate operating temperature. Make sure your fuel filters are clean and free of water, for obvious reasons.

 

[turbotodd]

Might be a little off-topic, but many moons ago I studied physics before I got sick. In class we observed the freezing and boiling points of water that particular day and the [odd] behavior of water while at atmospheric pressure, as well as at different pressures (from +100 psi to 400 micron vacuum). One of the oddities was that water effervesces under a vacuum, in other words it will change directly from a solid to a gas. That was weird to see. A block of ice that just gets smaller unless you shine a really bright light into the chamber then you could see some of the vapor "boiling" off. The other thing that struck out at me was how much pressure water can exert when it's near solidification. We had a pressure vessel that was made by the school's machine shop which had distilled water in it and a gauge that read to 100,000 psi. Stuck it in a freezer with a camera, and watched the gauge begin to rise at about 38°F. I forget what the temp was, seems like it was down around 34°, the gauge actually PEGGED (100,000 psi), then the STEEL vessel burst not long after.

Amazing what water can do.

The duck hunters have it down to an art; as do those who fish freezing and subfreezing waters. I get a few every year that have the prop shaft/gearcase housings broken out due to water sitting in the exhaust system and/or the lower unit (leaky seal(s)), usually around January through about March here. Then it begins to warm some and it becomes a non-issue. I don't fish when it's that cold. My hands are real sensitive to temperature, mostly cold temperatures, they'll quit working at which point they are useless. Can't turn the throttle grip, can't push the start button, can't run the trolling motor, and certainly can't turn the key in the truck to warm up. I once sat at the ramp for about 45 minutes because I'd been out fishing, hopped in the truck, got it started (5 speed manual), backed it down & loaded the boat, but my fingers couldn't grip the parking brake or turn the key a second time. Sat there for a while sitting on my hands until they were warm enough to "work". Only one other boater on the water; glad he was patient.

 

[jethro]

The best thing about freezing temps is no boat needed to fish!