</font><font color="blue" class="small">( Thanks for the follow-up responses... I started my tractor yesterday for the first time in about 6 weeks. It was in the mid 30s when I got it going. It took many minutes of cranking to get going, but it eventually did. The only way I could get it running was full throttle open-- This was on the fourth attempt, cranking for about a minute each time. -arthr31)</font>
Something's not right. I suspect you have bad fuel. That made similar problems for me last winter. Fresh diesel plus Power Service solved my problem.
After reading this thread I got curious and tested my YM240 (YM2000) to see what would happen, since I seldom start it in our coldest weather. It hasn't been started for weeks. Overnight low was 34, temperature in the barn now 48. I tried it without the Thermostart. (Ordinarily I would use the Thermostart and expect an easy start).
I always spin it first with the compression released (and zero throttle) to get oil pressure, then start spinning it a second time with the compression released to ease the initial strain on the starter.
Results:
With throttle at 1/3 (= about 1500 warm idle) it fired the instant I let go of the compression release, so I let go of the key too. It fired evenly but lost rpm during about 5 strokes. No smoke.
Throttle set 2/3 (= about 2200 rpm warm idle) it fired immediately as I let go of the compresion release. I held the key engaged for another second. It started without a fuss. Slight smoke for the first second until it reached 1500 rpm then I throttled it back.
Comment - This wasn't cold enough to be a problem. And obviously the colder it is the more initial throtle is needed.
I wanted to harvest the lone persimmon tree down in the back of the apple orchard so I tied my harvest buckets and ladder onto the loader bucket and drove on down - see attached. Yeah our winters are pretty mild.