ORIGINAL: rolland
If your HSN is screwed out 2 1/2 turns from flush you are running way to rich. You will need to screw your HSN in all the way untill it slightly bottoms out and then screw it out 2 1/2 turns.
The LSN you might want to screw in 1 to 1 1/2 turns from flush. These settings might be a little to lean for you weather conditions but the truck should run on them. I would also put in a new OS A5 glow plug.
There is also a possibility that it is time for a rebuild.
rolland
Yeah, make sure it's 2.5 turns OUT from all the way in. I am in Alberta, about 50 kms from the sask border (similar weather and altitude) and I have my LSN around 1.25 to 1.5 turns in depending on the season.
Other than that, check your linkage like PJ says!