I have a 84 mercury 150 blackmax. When you turn the key the starter ingages but the motor won't turn over. I have followed power to the switchBox (both) but there is not any power coming out of them. I just replaced them yesterday and it still does the same thing

I highly suggest you get a FACTORY service manual as parts changing can get real expensive. No spark can be as simple as kill switch lanyard is tripped to stator or trigger failure. You stated you followed power to switchboxes but there is not any power to be applied to them, any voltage on the blk/yel wire will damage switchboxes as this grounds out boxes when key is turned off. The stator and trigger from under flywheel supply the remaining voltages needed to operate.

I hot a clymers manul and had a frined help I bumded the key while he test and it show power to it but going out. So we ohm tested the switchbow and they showed to be bad. That's y I replaced them, I tried to pull the wires of the kill swith and they where not fastened by normal terminal some had wrap the wire around the connection so when I tried to pull it off the switc basically exploded can if I leave them disconnected it should start right. Thank you for your help.