Outboard motor lifetime fuel usage and emissions

[Jammer]

Mainly what I'm getting from the comments is that use cases vary widely, WOT vs. lower speeds, many hours vs. few hours per year, etc.


On engine life. Last week I just finished winter maintenance on a 1964 Johnson 3hp and a 2022 Suzuki DF2.5. They both run great, no reason an outboard that has been cared for can't last 60 years, especially in fresh water, as long as parts remain available.


Locally here it is common to find older 3 HP and 5.5 HP motors in good condition because they are/were widely used on canoes and duck boats where the usage is highly seasonal. These motors might only see 10 hours of use a year. The larger 9.9/10/18/25 HP motors that are/were more often used for fishing are much less common to find on the used market because they are typically run out and scrapped rather than overhauled. I think 50 hours a year is fairly typical for these and so most of the motors from earlier than around 1990 are usually run out, unless you can find one that sat in a barn for half its life.


As one data point, look at the Hunter H26 I used to have. It was manufactured in 1996 and the original outboard, a 2-stroke Nissan, was still working when I sold it after I moved it to another boat in 2019. 25 years on the back of a sailboat that was rarely sailed and often motored, probably at least 25 and not more than 50 hours a year, so between 600 and 1200 hours when I sold it, at which point it was still doing fine.