Mariner by Yamaha. What year.

[jprisbe1]

Just bought a '89 Bass Tracker Pro 17 with a Mariner outboard.
Can anyone tell me the year of the outboard?

Model: 40ELTO (what does the "O" mean"?)
Serial: 6E9 L 500909.
I believe the 6E9 indicates 1981 - 1983 but can't seem to find a 500909 serial number anywhere on the Internet.

Is there a corresponding Yamaha serial number I can use to purchase parts for this motor?

[Sequoiha]

im coming up with a late 88 or 89 40hp Mariner,, electric start, 20" shaft and power tilt and trim..

[jprisbe1]

Thanks.

Any idea what the "O" stands for?