What year model Mercury outboard has this serial number 09584425

Question edited for a lot more clarity.

They are normally listed by HP.

https://www.google.com/search?q=mercury+outboard+serial+number+lookup

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Product Line Year H.P. Model Number Model Description MERCURY 1978 115 1115628 MERC 115

Hello,

Mariner 4hp are identical to Yamaha engines.
You should find a sticker on the port bracket with serial and model number.
If that sticker has disappeard, an aluminum piece is stamped in the side of the cilinder. The numbervstamped in that round pieceis the serial number. I can convert that serial number in a year/model number...

Go to boats.net - Mercury parts - search under hp/serial range - select 20hp 2 cylinder - it will be under the first selection 0A730007 and up.

call mercury outboard they can tell you the answer to your question

Quiksilver marine dealers !

pinched rom another website:
Every Mercury outboard has a serial number label located on the transom bracket area of the engine. The latest serial number labels display a 2-digit number in a box at the lower right portion of the label. These digits coincide with the last two digits of the year in which the outboard was manufactured. For example, if an outboard was manufactured in 2010, the number "10" would appear in the box at the lower right portion of the label.