Yamaha 15 4stroke vibration fixed.

[River Explorer]

Had a vibration problem earlier. After ruling out a lot of areas on the motor I could only think of one thing. Had to be the shaft going to the lower unit. Sure enough it was. So the question is how can a motor that's never hit anything or had the lower unit off have this happen? Factory defect? It has at least a 1/8" sway to it

 

[boscoe99]

Factory defect? Not hardly. Don't think so. After six years did the metal of its own accord simply decide to get out of round by .125"? I have never heard of metal just up and changing its dimensions by that amount.

The motor might not have ever hit anything but has anything ever hit the propeller or propeller shaft? Without you even being aware of it?

Oh, six years without the lower unit having been removed for service?

 

[River Explorer]

Motor was on a trout boat and used first 2 years and had not been used since. Someone my have used it at the cabin and didn't tell me. It always had a light vibration but didn't know it was that. Just thought it was odd not having damage on the prop. I serviced it before using it again and saw the shaft move when turning the prop by hand.