I am now convinced it was gelled fuel that made sterting difficult. Once I added some Kero to the fuel and ran it through , the tractor started like it used to , down to the teens(deg F) without block heater. I did one gal Kero per 5 Diesel. I always use an addidtive , i quess I may have missed a fuel can or not added enough to cover very low temps. .....hope this helps someone else...bob /forums/images/graemlins/wink.gif