Yamaha ox66 Question

[One More Time]

I'm currently looking at a used boat with a 1997 Yamaha 250 EFI motor that I believe is an ox66 model. From what I've seen on a few forums, people seem to have issues with these motors and I'm looking for input on what quirks these engines are known for so that I can ask the current owner important questions to learn the history of this particular used engine. I know that all the manufacturer's motors are known for having some sort of weak link and I just want to know what to focus on with him in regards to maintenance and replacement of parts in any areas that are known to wear out. The current owner estimates that the motor has about 400 hours on it.

Rodbolt - I'd greatly appreciate it if you can provide me with any information, seeing that you have a great deal of knowledge on these motors.

Thank you for everyone's replies.

 

[jwbergeron]

Re: Yamaha ox66 Question

Its a great motor if its properly maintained. If the compression checks out, I think you're probably fine.

In addition to regular maintenance (i.e. thermostats, water pump, plugs), there's a few items to tend to, largerly due to the ethanol in the fuel: the vst filter needs to be cleaned annually, the 3 low pressure fuel pumps should be replaced every couple years (they're pretty cheap), and the the O2 sensor should be cleaned annually. Make sure you have a decent fuel filter (10u racor or similar) installed upstream.

 

[One More Time]

Re: Yamaha ox66 Question

From what the dealer told me about the engine, the owner has had the water pump replaced every two years and I did see under the one hatch that it had one of those external large blue Yamaha fuel filters (but I don't like that you can't see or drain the filter at the bottom like the Racor filters). I just want to really know what questions I need to ask him pertaining to the fuel injection system to gain a better understanding of if this engine has had prior issues and that's why he's selling it, and has the parts that frequently wear been replaced as often as they should. I just know that most people just don't maintain their engines like they should, and I don't want to take on their problems. Thank you for your input. I greatly appreciate it as I'm not that familiar with this kind of EFI system, coming from a 2005 Evinrude Ficht that didn't require much attention other than basic maintenance.

 

[rodbolt]

Re: Yamaha ox66 Question

fict was a blow up, about the same as my 07 175 ETEC.
not really many issues other than dirty fuel system components or dirty O2 sensor issues on that 250.
sweet running engines for the most part.
if you have a QUALIFIED tech check it out and you buy it, post back.