2015 Tohatsu/Honda Bf225

[rockb]

I have a relatively new to me 2015 Honda/Tohatsu BF225.

Ran great first 2 trips then 3rd trip alarmed shortly after I fired it up at the ramp.

Thought it was an overheat issue and did all the stuff to remediate heat but alarm persisted. Ended up getting the Dr. H and ran it and it diagnosed bad O2 sensor. I replaced that and everything seemed good.

Next trip it fired right up and ran great for 30 minutes or so and I slowed down to trolling speed and it ran great for another 45 min to an hour then as I went to throttle up it acted like it had water in the fuel. As I would try to throttle up it would start to die. Bring the throttle back to idle and it would be fine. I was limping it back and of course just as I got to the pass the alarm started going off. Kept it limping until I could get in the pass and to a safe shallow place where I could drop the anchor. I shut it off then just for the heck of it I fired it back up. It fired up throttled up to normal cruise RPM and acted like nothing was wrong at all except the check engine light stayed on.

Got it back to the house and hooked it back up to Dr. H and it is showing the same code it did before. Clearing the code with Dr. H does not extinguish the Check engine light.

Where would you smart folks say I should go next?

 

[jgmo]

I'm surely not the guru that you're probably hoping will answer but I have a question and a couple of thoughts about the problem.

The question:
Did you buy and then install the outboard on a boat you own or was this a boat and outboard package deal?

The question relates to my first thought about if the outboard is compatible with and is installed correctly on the hull. Improper outboard height can impact performance and could contribute to "swamping" of the moter when backing or quickly reducing power.

The first line on the Dr.H screen concerning the O2 code is about "possible failure" and speaks to the connection. It is often the case that the connectors for sensors can have hard to detect problems like:

Corrosion in the connector sockets that is hard to see or clean.

Poor fit of male pins to female sockets. This can be caused by wear from vibrations or bad handling and the use of oversized/incorrect probes

Terminal "push back" within the connector body that results in the terminals not achieving full plug-in contact because of the increased distance. Often caused by plugging in carelessly but also because the plastic body gets mis-shapened for some reason. Exposure to heat or stress from strain caused by short or poorly routed wires will cause this too.


Broken wires or bad crimps at the socket terminals resulting in poor and intermittent contact. Very hard to see without disassembly.

Broken wiring elsewhere in the sensor harness has to be considered for poor connectivity too. If that is suspected, load testing the wires individually combined with "wiggle testing" is the recommended method for accurate diagnosis. Ohm testing for broken wiring is often misleading because the amperage of the ohmmeter is so very low.

I see that fuel pressure is on that list too and I would always be interested in being able to test for that. Especially on a "new to me" outboard.

The O2 terminals in the ECM connector can suffer from the same reasons listed above for connectors at the sensor and might need to be examined if no other cause can be identified.

Good luck and hope you find the problem.