Volvo 28hp 2003 non turbo starting problem

[Malcolm]

I have a 2003 3 cylinder. Rebuilt the injectors and pumps and put in new piston rings and honed bores.

Always hard to start when cold ( 40 degrees f). Will start well on No 1 diesel. Needs to be cranked for 1 minute or more on No 2. Cranking speed seems ok.

Anyone know of a preheater kit? or other suggestions.

Thanks.