Yamaha OX66 or F225

[Parthery]

A properly maintained OX66 will provide years of reliable service. I've owned several....my current one has 1200 hours on it.

Does it start first try? Yes
Does it smoke? Yes
Is it louder and thirstier than a 4 stroke? Yes
Does it require oil changes? No
Does it go when I hit it? Yes

 

[seasick]

Regarding costs to repair the exhaust; Yamaha was offering the parts kit at a steep discount for about $600 but I don't know if that is still offered. Without the special offer, parts run about $1800 if I remember correctly.
If you are going to have the exhaust done, you should also replace the oil pan and the oil pump. A failed oil pan is the main reason that some motors blew up due to water getting into the oil. The oil pans have the same corrosion tendency as the exhaust housings. Changing the oil pump is just a good thing to do since it is easy to do when doing the exhaust.

The last person I know who had the job done spent about $3,000 per motor. Labor is expensive in my area.
I watched the job get done and although I do a lot of my own mechanical work, I don't think I would attempt the job. You need some experience to know what has to be done and in what order. There re a lot of parts that have to be disconnected and more importantly reconnected .You also need a hoist or crane to lift the powerhead.