Quad not starting or starting and then knocking off.

This might sound like a big problem but can quite often be the engine stop switch getting worn, damaged or weathered. Theres 2 philips screws on the bottom of it, when you unscrew them it comes apart in two pieces, behind the red switch theres a spring, as a temporary measure i pushed tinfoil in behind it with a needle to push the contact point out more, but long term this will have to be replaced.