My 12.5 hp 40 in cut murray won't start worked fine last winter when i put it up i've replaced the battery n plug an still won't make a sound

SOURCE: Murray Lawn Tractor won't go up hill

Your drive belt is worn/slipping

SOURCE: Need a belt. 12 hp 40 in. deck lawn tractor.

Hey...my name is Keith...im not sure which belt you are asking for...but the drive belt is a 37X61 and the deck belt is a 37X62..i hope this helps

SOURCE: can't find model number

there should be a data plate somewhere on the tractor with model and ser #. Usually it is under the seat. The motor numbers are usually stamped on the engine cover with model type and code.

SOURCE: deck trouble with a murray 40: cut mower

A hanger may have come loose from the deck that needs to be reattached.
Plus check your tire pressure, one tire with less air than the other will make it cut lop sided.

SOURCE: I have a Sears GT

I'm going to throw this quick one at you but there are several problems that can stop the spark reaching the plug. Check the connection at the seat switch. The "connector" has a built in switch in addition to the switch that it plugs into. This is designed to prevent people from unplugging the connector and installing a jumper wire to bypass the seat switch. If this is not making proper connection it will kill the spark. You may also check the pluger switch for the seat as well. Hope this gets you in the right direction.