Yes you need to look at the sensor and how it is mounted, it is normally fitted on two long bolts and mine was able to slide up and down freely when I first got it, so I made some spacers to keep it in one position.

note added
We must have been posting at the same time, good you got it sorted, never thought to mention that, the starter and glow wires should always be on the oposite side of the fuselage than the rpm wires.