I have a cherokee 140 with 160hp through Art's STC. I have Bendix Mags. Seems like lately the engine doesn't want to start until I relax the key to the "both" position. What could this be? I have a sky tech starter and it really spins the prop. I can hold the key over in the start position and it doesn't ever seem to fire until I begin to relax it. The mags check out good every where else. I have a jpi 730 installed and the mag checks on the ground and in the air are good.