How do you replace a solenoid on a lawn tractor - MTD yardman model 604?

Without the entire model number I can't tll you where to find the solenoid. But, if you follow the positive (+) battery cable from the battery it will go directly to the solenoid. Unhook the cable from the battery first. Then mark the cables that go on the solenoid so you can put them back on the new solenoid in the same positon. All you have to do is remove the wires from the solenoid and unbolt it from the mower. Then put the new one in it's place and hook the wires up just as you removed them.