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  1. #1

    Default Honda Bf225 02 sensor problem

    I recently purchased a boat with twin Honda 225's. The Boat ran fine until last week when I got a buzzer alarm on the port engine while idling. It apparantly is the 02 sensor. The dealer researched the engine's history and found that both engines had been serviced in 2008 with the exhaust pipe kits according to Honda Service Bulletin #56. This obviously has not resolved the problem. In any case, all I can do is replace the 02 sensor (it's under warranty) and hope for the best.

  2. #2
    Join Date
    Sep 2008
    Hague, Virginia, USA

    Default Re: Honda Bf225 02 sensor problem

    I think it would be important to try to find out why the O2 sensor failed. Sometimes they just do, but normally there is another issue.

    Make sure your exhaust ports are at least 5.9 inches above the water line when the boat is sitting in still water. The higher the better as long as the anti-cavitation plate is under water and properly aligned with the bottom-most point on the hull. If you have a motor extension bracket, then you can raise the anti-cavitation plate one inch for every 12 inches of offset from the transom. When you are running on plane, the anticavitation plate should be riding right on top of the water coming off the bottom of the hull.

    A loose or corroded wire from the ECM to the O2 sensor can also cause it to fail.
    CHawk 25 DLX

  3. #3

    Default Re: Honda Bf225 02 sensor problem

    Thanks Chawk_man. Yes, i would love to know how this happened. A Honda rep came out to the dealer, measured the exhaust ports and said they were just 5.9 inches above the static water line when the engine was in the "verticle postion". He gave the ok to replace the sensor. My previous boat had a Honda 4 stroke and I never had a problem with the 02 sensor in 7 years. I hesitate to even wash down the engines after use for fear of water getting in the ports. I spoke with another World Cat owner who said he replaced the sensors evety 2 years on general principal. If the problem is my operation of the boat I would like to know.


  4. #4
    Join Date
    Sep 2008
    Hague, Virginia, USA

    Default Re: Honda Bf225 02 sensor problem

    I wouldn't worry about washing down the engine, unless you're sticking the hose up the exhaust port. Changing out the O2 sensor every two years is a waste of time and money. When they go, they go.

    If there is any possibility of raising the engine and still maintaining the proper depth for the prop and anti-cavitation plate, I would do that. See my previous post.

    Two other operating items. When you crank the engine, crank it until it starts, or until you figure it's not going to start. When you crank in short bursts, ech time you stop cranking there is a (slim) possibility of water getting sucked in the exhaust ports if the valves and pistons are just in the right spot.

    Secondly, avoid coming off plane very rapidly, the exhaust pressure goes to near zero and a strong backwash can allow water to get into the exhaust tubes.

    Hope this helps.
    CHawk 25 DLX

  5. #5
    Join Date
    Jan 2009
    Venice fla,

    Default Re: Honda Bf225 02 sensor problem

    I had same problems I make it a point when pulling of trailer to tilt engines way up and when loading on I do same thing. I noticed when doing those loading and unloading my motor ports would be submerged if I didn't trim way up. I also make it a point when anchored or coming off plane to ensure motors our trimed way up to the point had a captain ask me a few months back why I always do that.. seems to have helped no more o2 problems as of yet

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