Just purchased a bass boat with a 2001 Yammie OX66 series 225 VMax with only 278 hours on it. Super nice motor,...and one of my purchase criteria was that the boat be powered by a Yamaha. From what little I've been able to ascertain, I think the OX66 refers to the type of fuel injection installed on the engine. I also believe it to be a salt water series motor,...but it has only EVER been used in freshwater. Can anyone clarify more about this particular engine, i.e., compression numbers, what OX66 refers to regarding the fuel injection, and what makes it internally different fro it's 2001 stable mates? Thanks,...I'm a gear head, so my curiosity is driving my need to know !!

It is a fuel injected 2 stroke. The OX 66 is yamaha's way of naming their injection system. The OX 66 is the last of Yamahas' standard 2 stroke they are simple and easy compared to the HPDI. Very dependable outboard. For the record I can't stand Yamaha with the exception of the carbed V MAX along with the OX 66. Everything else they make no thank you.

OX66 is a good motor. It is a simple EFI motor as opposed to the compressor type fuel injection motors. They are not terribly bad on fuel and oil unless you run them hard. When you do, fuel and oil will be consumed much more quickly. They are reliable and will even run reasonably well if not properly maintained. That's good and bad because depending on the owner, they may have just run it and not done much maintenance other than basic change the impeller, LU lube, and spark plugs. If you don't know what previous maintenance has been done, I would recommend going through all the fuel system maintenance for piece of mind. Chances are the injectors have never been touched, so pulling them and sending them off over the winter to be cleaned and calibrated should be on the list to do.

Thanks to both of you. Good intel.

I didn't think that it was possible to get the hours on these motors.. Seems like that's what I was told or read somewhere. They are very good and reliable motors

Two of the panel gauges are multi function Yamaha gauges and one of has a mode for engine hours and it shows 278.

Also, there is a Yamaha section on BBC. Lots of good knowledgeable people there.

my carbd Vmax drinks Gas and oil faster than anything Ive ever seen, but runs like a champ, and has never had an issue