Suddenly, It's really hard to shift into Reverse on my 1998 Yamaha C115 2 Cycle

[Soundear]

Thanks for the responses ........ I attached a photo of the area where my trim tab mounts. It's this location that the values of the casing offset to gear placement of a lower unit can be found. It's stamped at the factory and is unique to every LU. This is how you calculate shims for each of the three gears (Forward, Reverse, Pinion) using the + or - values stamped in this location. By using the stamped value with a formula, you can determine the shim thickness needed so the gears mesh correctly. My photo clearly shows R + 2, and the P - 4 values to use; it's my Forward Gear stamp that appears to read F + 9 2x If no one else has an idea, I'll have to go to my local dealer to see if they have a clue. Leave it to me to find the "odd casing" for a weird calculation......my luck, it's probably 1 in 5000 LU casings made!

[Soundear]

Hi all!
It's been several months since my last post in December 2020 when I asked several questions about doing my own LU rebuild on my 1998 C115 motor. Just recently, I refocused on rebuilding my motor and in the process, learned a lot. I realized there's a lot more to learn and have an enormous respect for marine mechanics. Since then, I managed to buy the Yamaha specialty tools at reasonable prices which are needed for calculating the shim sizes for the Forward, Pinion, and Reverse gears off of Ebay. I replaced everything and carefully have it all installed and ready to measure backlash before I re-install my LU except...... I have a problem:

After I tighten the upper driveshaft bearing housing down, the driveshaft will not turn; it's locked! I can't turn the driveshaft by hand even if it's in neutral. I re-measured everything at least 2x and can find nothing wrong. At first, I thought the pinion was over shimmed making it too tight, - but even with no shims, it will not turn freely. I did notice that with no gears in the gearbox at all with only the driveshaft sitting in the lower needle bearing, it turns easier in the clockwise direction vs. the counterclockwise direction. Is this typical behavior of the lower needle bearing because it is designed for a CW motor rotation? - or should that not matter and I could have possibly purchased a defective needle bearing from my local Yamaha dealer? I checked placement of the lower bearing in the driveshaft column and it is installed exactly where it should be according to the Yamaha service manual. Does anybody have any suggestions that may help me understand why I have this problem??

[panasonic]

No it's not typical for a bearing to be like that....should turn either way. If you can turn the drive shaft without any gears installed in the case and can't after putting the gears in then the pinion is to low and binding everything up. Something is not right...you may have damaged the needle bearing installing it..not hard to do.

I dont know what to tell you but to start over again.

[Soundear]

Thanks for the suggestion Panasonic. I did move the bearing a few times looking for the exact measurement as indicated in the service manual. There was also a contradiction between Clymer and Seloc on which direction the "Japan" stamp face. It's driven (pulled up) from the bottom, so I placed the stamp facing the driver (upside down) I put 90 weight LU oil on it each time, the service manual indicates grease points instead.I think I'll just buy a new lower bearing and carefully install it again. Being the LU will eventually be submerged in 90w Hypoid oil when complete, I guess it's ok to mix Yamalube Grease and Hypoid Oil. Thanks again for the advice!