The Mercury 3.5 4 stroke outboard was my second outboard purchase. Back in 2010 when I was just getting started in boat fishing I wanted a lightweight outboard to power my inflatable boat and get me a mile or so out to the fishing grounds off Skinningrove, where I was living at the time. I recall paying £580 at the time for the engine. I already had a Mercury 9.9 2 stroke but wanted something lighter and easier to manage as I would be setting up the boat solo.
The running in process was as follows:
First hour: Run engine at various speeds up to 2000rpm or half throttle.
Second hour: Run engine at various speeds up to 3000rpm or three quarter throttle then go full throttle for one minute in every 10.
Next 8 hours: Run engine at various speeds as required but avoid continuous full throttle for more than five minutes at a time.
I made a video of my first outing using this engine.
It did the job but was a bit under powered for a boat of this size, the 13ft Humber, so I decided to keep it as an auxiliary engine instead and use the 9.9 Mercury as the main engine.
Mercury Outboards: https://www.mercurymarine.com/en-gb/europe/
Humber Inflatables: http://www.humberinflatables.co.uk/
Other videos from Skinningrove: https://stufishing.com/tag/skinningrove/