Total newbie sled question

[emtorn]

I see people talking about sleds overheating because there is no snow cover on the ice. Not understanding this at all. Have been thinking about getting some kind of transportation for next season and was initially leaning toward a wheeler cause I could use it hunting too but after seeing all the wheelers getting swallowed up by the pressure cracks on my local lake and the sleds able to hop over them pretty well I am starting to lean the other way

[Clear_Ice]

By no means am I an expert, and someone correct me if I'm wrong. On a liquid cooled snowmobile, your coolant runs above your track and is cooled by kicked up snow and ice, and then recirculates to your motor and cools that. No snow equals warmer coolant. This is why liquid cooled sleds aren't as good with little snow, but that's something that can be solved with  ice scratchers. Hope this helps!

CI

[jethro]

That is correct. On liquid cooled sleds, there are heat exchangers (think the same as the radiator in your car) that generally run under the seat (inside the tunnel) that get's cooled down by snow constantly being sprayed from the track. The snow flap on the back is critical to keeping some snow inside the tunnel and cool. Some sleds cool much more difficultly than others like high horsepower sleds and ones with a lot of suspension. That's why sometimes you might see people on sleds getting into the deep snow and pinning the throttle. It's called trenching and it's not because the guy is just looking to make noise or look cool, he's probably overheating.

The ideal ice fishing sled would definitely be a fan cooled motor. Obviously they do not have heat exchangers. They can also sit and idle for any length of time whereas a liquid cooled needs to be shut down if you are sitting still. However, there is another reason sleds need snow to work- lubricating the track. The track actually sits on two pieces of very hard plastic called "sliders" or "hyfax" and runs on that. The wheels you see are more to keep the track centered on the skid more than anything. The track has metal clips that ride on the sliders. If there is no snow, there is no lubrication for the track, the metal clips begin to get real hot from friction and in the worst case you will melt the sliders and the track will seize to the slider/skid. In the old days we used to carry around a bottle of dishwashing soap and squirt the sliders every so often if we had no snow.

The ice scratchers that Clear-Ice mentioned can help a bit, but if it's glare ice, they won't keep a high horsepower liquid cooled sled cool. They are actually more beneficial for lubricating the track than cooling the sled.

[jethro]

Then of course there are real vintage sleds that are all bogie wheels, no sliders. You can run these sleds on glare ice all day long. Actually you could ride these all summer long, which we did, when we were kids.

[Fishin_Chip]

If you are considering a newer sled, some of the Ski-doo utility model 4-strokes have an auxiliary rad and fan.  My Expedition Sport ACE has never come close to overheating. 

You would still need the scratchers to keep your hyfax lubed, but engine temp shouldn't be an issue.

Cheers!

[bart]

I'm still a newb, as far as snowmobiles and I asked the same questions not to long ago, here are a couple of responses...


"Liquid cooled sleds have aluminum coolers (Heat Exchangers) mounted in the tunnel or running boards to cool the engine by contact with the snow thrown up by the track, they do the same thing as the radiator in your car. Fan cooled sleds like yours just use a fan driven off the crank shaft and shroud to cool the engine, much simpler and keeps the weight down."


"Yes, for the most part, fan cooled sleds are better as ice fishing machines, especially in low snow situations. About the only time it's better to have a liquid cooled machine is when there's lots of deep snow and slush, and the temperatures are well above zero. A liquid cooled machine will remain cool, using the loose snow/slush being thrown around inside the tunnel for cooling, but a fan cooled sled can over heat due to the higher air temps and large load on the engine from trying to power through the slush."

On the flip side, on a cold day with little to no loose snow on the lake, the fan cooled sled will run like a champ, but the liquid cooled sled will start to overheat. I've run my studded, fan cooled Tundra on almost glare ice last season several times, and the only issue was the lack of snow to lubricate the sliders. Any of my old liquid cooled machines would have overheated before I got to my fishing spot.




I have a thread on my sled journey, a lot of members were very helpful, sharing their experiences and knowledge on this subject... 

http://www.iceshanty.com/ice_fishing/index.php?topic=154533.0


hope this helps, bart