Have you checked the fluid resivor,tilt the motor up engage the tilt lock then look for a black plastic cap,should have a slot on top that a flat head screw driver will fit into,the seals on mine were bad and topping off the fluid bought me over a year of use before replacing.
Hate to say it but you sound like your where i was at when i replaced everything.
Ouch! Shop around and you can buy the entire outboard for that much $$.