2005 Yamaha OX66 200HP Fuel Injected

"This problem started last wee

"This problem started last weekend since purchase of outboard in '05. At WOT (5400 RPM), it ran fine for a few minutes then it slowed down without throttle movement. I placed it in neutral then WOT...the max RPM was @ 3700. It lost its power. It idles normal in neutral.

The motor currently has 175 hrs, never been professionaly serviced except in its 20th hr. I ran the boat at least once a month, use Yam. Ring Free additive @ almost every fueling & have replaced Yam. water/fuel separator filter three times(third one this morning). I also replaced the sparkplugs, replaced fuel filter element and lower unit oil.

I used the boat this afternoon and the problem happened again. Is there another fuel filter in this engine? Or do I have a major problem?

Please advise. Thanks."

"Ed,

I believe you can atta

"Ed,

I believe you can attatch a flash harness to the warning circuit. The dealer could tell you if this model has this feature. It will flash service codes that tell you what is malfunctioning while the engine is running.

Tony"

yep i would plug it in to YDS

yep i would plug it in to YDS software and go from there

any alarms?

Thanks for the reponses but th

Thanks for the reponses but this problem sounds like the O/B needs to go to a Yamaha professional.

No alarms just no power.

I mean no power like I previou

I mean no power like I previously mentioned.

"i know whats wrong. a few thi

"i know whats wrong. a few things do need to be verified at first compression? fuel pressure when problem exists.if those to check out then most likely the o2 sensor is bad, dirty ect. can be tested. plugged shuttle or bad o2 sensor gaskets. it is very important to reguarly re sink throttle plates and tp sensor this is done with an ohm meter and a test adaptor. plugged high pressure pump screen or o2 sensor problems. sounds very likely. keep using ring free. you would have had problems well before this without it. 02 sensor must stay clean"

you should also replace fuel p

you should also replace fuel pump diaphrams every couple of years in that engine. they are cheap and easy.

"Thanks guys for the responses

"Thanks guys for the responses. Shawn, I went to a local marine dealer the other day & spoke & described my problem to their svc mgr who specializes with Yamaha OB. He actually mentioned & showed me the picture in the computer & location of the screen you talked about.

I'll post once I get the OB repaired."

Does anyone know where I can p

Does anyone know where I can purchase an o2 sensor for way less than $370?

"Shawn, you're right! The

"Shawn, you're right! The sensor was bad. It's been replaced & I'm back in business. Thanks guys for your responses."