Having problems with the the Victa 2 stroke 160cc. The kill wire set-up allows me to start the mower but not turn it off with the throttle control. The kill wires go into a rubber boot and when the wires (terminals) touch there is no spark. If I jiggle the wires and pull one out slightly then there is a spark but then I can't turn the mower off. When I first started working with the wires I noticed that one of the wires had a perished rubber sleeve but now with all the trying to get this to work the sleeve has fallen to bits. The throttle control has no effect on the situation, if I get a spark with throttle off, moving the throttle switch still results in a spark, if I don't get a spark with throttle off, I still don't get a spark with throttle on. What can I do now?