Here is some useful information describing model C magneto installations on earlier Wisconsin engines followed by the later XH series to keep yours alive and well by kind permission from Wico. Most service parts are still available from Standard magneto of Chicago. Always check any old style plastic condensers. We hardly ever see a good one. They develop electrical leakage over time and will cause a weak spark and pitting at the points. Before installing, be sure to fill both oil wicks. That is what the two pipe plugs are for on opposite sides that never seem to get oiled. Fill to overflowing. Oil cannot get on the points. This mag has two sleeve bearings that support the armature that usually got no respect.
Alway check the plastic condenser part # X1413. Many bad ones out there.
Sorry to say that your magneto is probably out of warranty.
Here is some Wisconsin Engine application information for the later Wico model XH series magnetos. There are enough different magneto configurations (right hand,left hand, base mount,flange mount, special flange mount, gear drive,which gear anyway?,1,2,4 cylinder, etc... ad nauseum) to drive one looney. Some magnetos simply have a Wisconsin part number regardless of the magneto manufacturer. As Will Rogers spake, "Life gits tedious don't it?" and very annoying at times. Here is some dealer application information to help find the right magneto for your Wisconsin engine.
Here is some info for the later Engines