hello, i have a wards gilson lawn tractor, its a twin, 16 horse power, model 33470A, serial # 9284a1801. i think the coils have gone out, is the any way i could test them to see it they are good? will any other gilson coils interchange with this model? also i would like to find a wiring diagram and would like to know the year this model was made. Thank You roger.singletary2011@yahoo.com