My 4150 sometimes starts when the key is turned but sometimes I have to hold it in the start position or switch it off then on repeatedly and it starts. This morning I started it, -20c, with a boost, blew 1/2 my driveway and it lost power and quit. I started it again twice with a boost. Btw the battery was fully charged when I first started it with boost assist. Does anyone have any ideas as to why it quits and why the starter switch doesn't always start it. Also dash lights go on when I turn the key even if it doesn't engage the starter.