OMC outboard does not start

I recently purchased a 1985 20 foot cuddy with a 115hp OMC outboard. The engine would start only when the throttle is in the partially forward position (would not start in the neutral). I was able to take the boat out once but the engine would continue to stall unless the throttle was in the mostly open position. Then when coming back in, the engine stalled and would not restart. I was able to drift in the rest of the way with the dock insight. I have since changed the plugs, replaced the gas and oil but have had no luck. The starter engages and the prop will turn (if the throttle is not in neutral) but the engine will turn over. I have not changed anything else. I would rather not start replacing the coils and other components without knowing what the real problem is. Any help would be greatly appreciated This is my first boat. Thank you.

The proper start procedure when cold is this....1..pump the bulb til it is hard...2..place the control handle in neutral..3..lift the throttle advance lever ..4..push in the key(to choke or enrich the engine) and turn the key to turn the starter..the engine must turn a minimum of 300 rpm to produce spark to fire the engine..you may have to play with the choke til the engine warms a bit...if it starts to die just push it in until the motor picks back up etc..
the motor should turn over only when the shift lever is in neutral....this is a safety feature that prevents starting in gear....the little lever on top of the controls gives you limited throttle advance to assist starting when cold..if you truly have to put the motor in gear to turn the motor then the neutral switch in the control box is all out of whack..fix this first..