I too had an MVVS 160 that gave me fits trying to get it to run. What I found was the wires from the Hall Effect sensor had been burned. Put new ignition on it and it ran fine, so I very carefully reworked the wires on the old ignition and now it runs like a wild monkey. BTW those wires are not just single wires, they are shielded cables so you have to be very careful if you have to repair them.