Here is the real truth on this issue, and not "common knowledge" or decade old experience.
1. You rarely need "parts" for outboards.
2. Parts can be obtained for any engine anywhere in the world by simply flying them in with a commercial shipping
service. The cost is usually the same as charged locally, if they even have the part.
3. If you think you can get "parts" for a particular brand simply because you see dealers for that brand in your area, think again. Very few places stock parts anymore. The local dealer will simply order the part and you will wait for it and pay a premium. Yes, they may have oil
filters and zincs (you should carry those yourself), but not carburetors and pistons and exhaust
manifolds, etc. For example, you cannot get a carburetor jet in Panama
for the Enduro 15, even though those are the most widely sold
engine there and there are several large dealerships. You can either place an order for one and wait for an unspecified time, or get it yourself cheaper from the US in 3 days.
Go ahead and test my thesis on this in your cruising grounds. I have in the areas we have been cruising, and found out that dealers find it too expensive to actually stock parts and now simply order them in as/when needed. If you are staying around St. Martin or the like, then you will have better luck with this than if you go further afield.
4. Yamaha 2-strokes are not all the same. Many of the parts for Caribbean Enduro's do not fit the other 2-stroke models sold elsewhere. Tohatsu is better, and their parts also interchange with Mercury
2-strokes. But you will still have to order them.
5. Mechanics everywhere have seen lots of 4-stroke engines, and have been working on them for years. In the San Blas Islands, the Kuna indians regularly strip down and rebuild
4-strokes right on the beach. If you are reliant on some shade tree mechanic
in the edges of nowhere that only understands one particular 2-stroke engine, then you should spend 30 minutes with a manual and gain his knowledge for yourself.
6. Buy a service manual for any engine you choose and any mechanic
anywhere in the world will be able to work on your particular engine and even order parts.
7. 4-stroke engine weights have come down dramatically over the past 15 years. The much vaunted 2-stroke Yamaha 15hp Enduro weighs 87lbs. The 4-stroke Suzuki 20hp weighs 97lbs (and has 5 more HP).
8. The remaining weight difference between the 2 and 4-stroke engine will be wiped out and surpassed by the extra 3 gallons of fuel you need to carry with the 2-stroke.
9. In 5 years of cruising the entire Caribbean, we have seen equal problems with 2 and 4-stroke engines. Neither appear to be "more robust" than the other. 95% of all problems were water
in fuel. All of those problems could be solved
if owners simply installed an external fuel filter/water separator.
10. The only shining moment for 2-strokes over 4-strokes is when you drop them overboard
. The 2-stroke will be running like new within 15 minutes of retrieval, while the 4-stroke may be permanently damaged if it was running when it takes a swim. If it isn't damaged, you have a day's work to get it running well again.