What you have described in regards it throwing the prop is exactly what my mate is having it’s also a pig to start ive got a number of OS motors and that 70 I was telling you about was a nightmare it to back fired at full revs detonated in the crank I tried every thing I knew and this 200 my mate has is doing the same thing might be time for that asp rich
pr lean its a nightmare to keep at a steady rev in between throwing the prop