[MarkSF]

With a used outboard, it's all about provenance. The best engineered outboard can be ruined by careless use - particularly salt water use without flushing afterwards. You're looking for a conscientious owner, rather than particular brand. The good news is that just about anything is better than a Seagull!

 

[MarkSF]

Yamahas are very well engineered. I know because I had to rebuild my 6SF due to extensive interior corrosion due to previous owner neglect. Someone had bolted the engine block to the lower unit with a massive amount of body filler to seal the exhaust!

I had a Tohatsu 3.5 4 stroke (43lb) on my 16ft Wayfarer, great little motor that sips fuel. The Tohatsu is also badged as Nissan and Mercury. (so is the 2.5, which is the same engine but restricted, I think)

All small 4 strokes can be finnicky about keeping the jets clean, but good fuel practices keep this under control (by good practices, I mean only use fresh fuel less than 1 month old, use fuel stabiliser, run the carb dry or drain it after use)

 

[MarkSF]

I'd also avoid ones with no external tank connection. Hanging off the back of the boat trying to pour gasoline into the outboard in the middle of SF bay and it's typical chop, is not something I'd care to repeat.

The Yamaha 6hp 2 strokes are superb, you have a twin cylinder while most small 4 strokes are singles, so smoother and quieter, at least at partial throttle.