You have a 'Large Frame' Bolens and I believe they all came with the Wisconsin 12 hp engines. Wisconsin parts are still available through their distributor network, go to the following link and find your local dealer:
They can also help you with the engine operation and service manual. For more information on your tractor and attachments come join us in the Bolens Club listed below.
By the way - the 1250 is a very nice tractor, a real beast.