2006 BF225 Constant alarm when engine cranks up

I just bought this used 225 Honda with 465 hours showing on the hour meter and installed it and the controls and wiring harness that came with it. It has a continuous alarm from the time the engine cranks up. This was a repower from my 1996 150 Johnson Ocean Runner that I bought new. to the Honda. The reason I mentioned that was to let you know this is my 1st Honda outboard and I'm not familiar with them. But I am mechanically inclined so any tip/checks anyone could give me would be greatly apricated.

Sounds like you have connected something incorrectly , get a manual and use the wiring diagram to double check your installation, there is no quick answer other than perhaps you've earthed a wire that shouldn't be

Do you have the four-light key switch - green oil pressure, red ACG (alternator), red overheat, and red MIL (check engine)? If so, do any of the lights come on or blink while the engine is running? Does the green oil pressure light stay on?

Attached is a wiring diagram for a duel engine set up, but you should be able to figure it out for a single engine set up.

View attachment Electrical Diagram Honda Digital Gauges Dual engines.pdf

Yes I have the 4 light key switch. When the engine cranks the green oil light comes on, I'm assuming that's supposed to light up indicating it has oil pressure.

I noticed my digital trim gauge wasn't working so I started checking the wiring and couldn't find any problems. But in the process of checking I unplugged the T&T sensor and cranked the engine and the alarm was no longer sounding off. I plugged it back in and it started sounding off again. Like I said in the beginning the gauge wasn't working, so I put a new sensor on and as soon as I plugged it in the alarm started sounding off again. The T&T works fine just not showing on the gauge. All wiring seems fine from the best that I can tell. Any suggestions? I hate to buy a new gauge and it not fix the problem.

Do you have the separate t/t gauge, or the one built into the tachometer gauge?

Since the t/t appears to be working well, I suspect that you have a wiring problem to or from the harness. First, I would check the trim angle sensor plug on the front of the engine. It sits below the red service plug connector. I think it is blue. I believe that it is the bottom-most connector among that group of plugs. It has a 3-p connector. Unplug that and check the contacts and the wires going into the plug.

If not there, I would go to my wiring harness at the console and find the trim sensor wire - yellow/blue - and check connections there. See the diagram I posted previously at #3.

Did you happen to figure out the issue? We just ran into this problem yesterday on the way back in. We have twin Honda 225s the port motor would sound an alarm after hitting a wave hard, I would idle Motors back to neutral turn off the port motor and restart and alarm would be gone. Happened about 4-5 times on our 65 mile run back in. Starboard motor did it once as well..