Yamaha outboard

I need some help with my moto

I need some help with my motor. I want to replace the impellor but i dont have info about the building year! The nr on the motor is L307071. The motor has 55HP. Further I can't open the lowest part of the motor because it's thigtened very much. Does someone know how I can solve this problem so I can replace the impellor. I also need to know the buildingyear for a owners manual

" That number is part of a ser

" That number is part of a serial number. The "L" means that it is a 20" motor, the following six digits are the serial number. There should be a three digit prefix in front of the "L" and there should be a model number very near the number that you found. It probably looks like "C55XXXX". You either need the model number or with the three digit prefix in front of the "L", most dealers can figure out what you have. If it is a "C55", it was probably built between 1989 & 1993. The gearcase should drop after you have removed all of the fasteners. They have a splined, rotating shift-rod like Mercury. There may be a hidden fastener under the trim tab. "

" Thank you for responding, th

" Thank you for responding, there is indeed a number for the L.... That number is 663.
Is it possible that the model is 55AE? "