Posted by Sherman in Idaho [72.47.153.28] on Thursday, May 15, 2014 at 11:59:00 :
In Reply to: Re: Not quite the same, but may still be of interest: posted by WayneH [68.32.120.247] on Wednesday, May 14, 2014 at 19:00:01 :
The first time I took my Sno-Cat out it did fine all the way up to Moon Pass, but on the way down it progressively lost power unit it was going as slow downhill in the tracks it had already made as it had gone uphill making the tracks. The temperature was in the 30s and it was a rather damp but not foggy day. When I got back home and looked, the carb throat was iced up to about half the size it should have been. The heat riser was the kind with the quadrant and it had been set to summer position (no carb heat). When I separated the manifolds, the passages under the carb were filled solidly with soot that I had to drill and scrape out.
So, yes, the heat riser serves a purpose. It won't make any difference in starting (it's not a choke), but it will prevent icing in cool, humid conditions. Why anyone would set the heat riser on a sno-cat to "summer" is a mystery, as is how they could put up with it that way. I set that one mid-way between summer and winter and it's been fine ever since.