Have a 30 year old 3016 with 1200 hours on the B&S Vanguard -original engine. Thought I had a problem with the fuel shut off selonoid, but after replacing it, still does not open after turning the key. Also headlights and electric clutch will not function when the key is in the "on" position. I recently replaced the ignition switch with a new one which got the tractor running again- for awhile. Can anybody point me in the right direction as to what my problem might be. Thanking you in advance for your assistance.