Honda BF225 Electrical Problems

Well after changing out the ECU i got about 40 hours on the motor before running in to more problems. After sitting for about a week I went to start it one day, but when I turned the key it seemed as if the batteries were dead. The next morning I hooked up the charger and found both were above 90%. I put the motor back in the water and tried cranking again but this time got nothing; not even a click from the relay. When I went to trim the motor back up, the trim motor didn't run; although the control relay did activate. At this point I also noticed the tachometer was very dim, and would flicker and die when trying to trim the motor.

The first thing I tried was to swap back to my old ECU, and got the same response; trim worked initially, but after trying to crank there was nothing. This is the way things stand now.

I've done a fair amount of trouble shooting but am at a loss; below is a list of what I've found.

• Batteries are both good; swapped them made no difference but they had plenty of power (not falling off under load). I have pot puller with a 3/4 hp motor that they both ran no problem. I also cleaned all the contacts and terminals, although they weren't very corroded.
• The Perko battery switch is good, I had steady power at all terminals.
• The starter solenoid has power on the main terminal but none on the S terminal when the key is turned. When I try to jump the solenoid directly i can sporadically get it to click, but not nearly as consistently as I expected. I suspect that the solenoid needs to be replaced at this point.
• When trying to run the trim motor or turning the ignition on (to accessory) there is a sharp voltage drop, from 12.5 volts down to 2.6 when running the trim motor, and approximately 4.5 with the ignition on. I measured the drop at the starter, ACG fuse, fuse box, and relay input.
• The ACG fuse is good, good continuity across all terminals.
• The fusebox connections are all good, continuity checked out as per the shop manual.
• The main relay was good according to the continuity tests in the shop manual. However, I never found power to the S terminal on the solenoid.
• The trim control relay is good.
• The trim motor is good.
• Voltage drop still occured when both trim switches, the ignition switch, and the emergency kill switch was disconnected.
• The neutral safety switch had continuity as per the shop manual.
• The power wire (white/black) going in to the ignition switch had a continuous 12 volts; this was the only place I didn't see a voltage drop.
• Jumping the ignition switch from the white/black to the black/yellow wires still saw no power to the s terminal, although I could hear a relay clicking.

Hopefully I haven't missed anything in the description, I've tried several things over the past few days. I am not positive but I am fairly certain that there is solid power to the relay on the white and white/black wires; I am not sure about the black/yellow switched wire (definitely need to check this). It seems like the relay must be bad but I have tried two different ones with the same result (although neither were brand new). Perhaps it is in between the gauges and the relay. I also worry that the ECU is fried, along with the starter solenoid. Is there anything else I should check?

I have the DR H diagnostic but it is unable to establish communication with the motor (this is what makes me think the ECU is done for). I'd greatly appreciate any advice or suggestions on what else to check.

Most likely you have a bad connection or bad battery cable between the battery and the engine.

Connect you meter to the big positive terminal on the starter and a good ground on the engine. Operate the trim switch on the engine and see if there is a big voltage drop....there probably is.

The trim works independently of the main wiring harness or key switch assembly....so it is good to use it as a test load.

If the voltage drops way off, then move your ground test lead, to the battery negative terminal on the battery. Test again. If the voltage drops again, then you have a continuity issue in the ground/negative side. If not....

Then put the negative test lead back on the engine ground and move the positive test lead to the battery positive terminal on the battery. If it drops, then you have a continuity issue on the positive battery lead somewhere between the battery and the motor.

Then you just have to narrow it down.

Mike