I think there’s two scenarios for dealing with a kicker in sub-freezing temperatures;
1.) You’re going to occasionally be using your kicker when you get to your fishing spot and tilting it up when using the main motor to get to the spots.
In this situation, once you’ve lowered the kicker into the water and started it up, you’ll get cooling water flowing through the motor. For the rest of the trip, I keep the motor down and in the water whenever I’m not up on plane using the main motor. For example, if I’m using a bow mount trolling motor or anchored. Generally the drives to new spots are short enough for me that I don’t think water inside the kicker will have time to freeze up, especially if the kicker is warm. Once I get to the ramp and pull out, I lower and raise both motors a couple of times to help drain out all the water. I’ll also hit the starter to spin them for a second or two. There’s debate whether spinning the motor is needed or even harmful but I’ve not had a problem in 10 years doing this. The impeller is wet.
2.) The second situation is where the kicker is not going to be used but is just along for the ride.
Because the water has been previously drained, there’s no need to worry about it freezing in the motor. The concern will be that the lower unit gets a lot of ice buildup as shown in the photo, and water also enters the hub of the kicker and builds up in there from waves and splashing if it can’t be raised high enough to avoid this. It seems like the hub could fill with water and as that water freezes and expands it could crack the hub. It seems reasonable to think this but I’ve had my Yamaha T8 kicker “along for the ride” for 10 winters now and have never had a problem with this happening. I think perhaps as the water splashes in there, it slowly builds ice on the surfaces so it does not have the expansion forces to cause a crack. As far as using it for a “get home” motor after it has the ice build up, it shouldn’t be a problem. I’d just let it soak in the water for a while before starting it. If ice has completely filled-in the hub, perhaps the exhaust could be blocked and the motor wouldn’t run until the has melted enough to let the exhaust gases exit. I wouldn’t worry about the pisser as it might be frozen but that doesn’t mean you’re not getting good cooling water flow.
I know a lot of guys have kickers on their boats that they don’t use during winter trips and I’ve never heard of a problem. That doesn’t mean it doesn’t happen but I’ve never heard of it.
Boone