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New 150hp Honda will not start but tries

PaulBF150

Regular Contributor
So new motor never run.
Wired it up (had to buy adapter cable to compensate for old circular connector t the new square one)
Turned on ignition switch heard the 2 beeps oil and water temp LED lit for a bit (however the MIL nor Battery lights can on at any time). Checked wires seem okay.
Heard relays switch and high-pressure pump turn on for a few seconds
Heard starter solenoid click
And nothing more (no cranking)

New battery.
Disconnected starter solenoid enable wire, and jumped the solenoid terminal to +12 and engine cranks

All fuses good
Neutral switch in neutral (closed)
Emergency Kill switch open

Seen that control wire for starter relay heads into the ECU for Air Fuel Mixture line (Measured continuity from relay coil to that line), although the schematic I am using has control of relay solely on ignition switch function.
Not sure where to go from here???

Help is appreciated.
 
Hi,
I don't have a wiring diagram for this one but just a quick thought is that this might be something going on with the neutral start switch or the wiring for it.
Good luck.
 
Sorry, I see that you checked the neutral switch.

The starter magnetic switch clicking indicates it's getting voltage but is it enough?
I mean, high resistance in that "trigger wire" would keep it from fully firing the solenoid.

Good luck.
 
What control are you using? Is your smaller positive battery lead connected to the battery? Also check for a good earth.I had this issue twice on the new v6 motors, both were due to a bad earth comnection
 
Thanks for the replies.
Running to a dealer is the last desperate action since trailering a 25 Grady white requires some skill plus trailer needs work to get it road worthy.

As for power I think that is good since I can crank it over when I apply power to solenoid with wire removed. I may have to put oscilloscope on power line to ECM to see if something is dropping out.

The new motor has 2 +12 power leads 1 a heavy gauge wire connecting to starter, the other has an inline fuse arrangement (not sure why it was wired from Honda that way). Both wires connected to DC Switch to a new battery.

Also, with monitor control signal to the relay in fuse box that controls the starter solenoid, see what line is dropping the ball.

There is this Black/White stripped wire that is routed from Ignition switch to this relay, but it is also routed to the ECU to an Air/Fuel Mixture line like I posted previously. But now going to investigate fuel pressure. I see fuel in inline filter/water switch bowls, but not sure fuel is in the Vapor assembly where the high-pressure pump is located. See if I get any pressure for that brief time pump is activated.

The new motor wiring is slightly different to the older motor. Not seeing the MIL lamp briefly illuminating like the other motor , don't see the Charge Lamp going on either. I checked the wires but this time I will back feed power to Remote (definitely with motor connector removed).

Wish could find wiring for the new motor 2023.

Also going to hook up Dr H on motor to see what it reports. I was going to do that before, but 2 different laptop computers crashed on me.


I took a break today from it, but now getting back at it (15:30).

Any other ideas are worth investigating.
 
I double checked the boat wiring, plus simulated switch function by applying applicable jumpers on new motor connector. Get same results.
Checking continuity from motor connector to control replays the signal that activates the starter solenoid is coming out of the ECU (my older motor the Ignition switch controls the relays as depicted in applicable schematic. New motor is wired differently.

Reached out to Dealer BOE Marine and also Honda Service. Honda Service basically said can't help you technically.

Only last resort before trailering boat to someone, is to purchase new cable and Ignition panel. Just can't find part numbers for them.
 
So new motor never run.
Wired it up (had to buy adapter cable to compensate for old circular connector t the new square one)
Turned on ignition switch heard the 2 beeps oil and water temp LED lit for a bit (however the MIL nor Battery lights can on at any time). Checked wires seem okay.
Heard relays switch and high-pressure pump turn on for a few seconds
Heard starter solenoid click
And nothing more (no cranking)

New battery.
Disconnected starter solenoid enable wire, and jumped the solenoid terminal to +12 and engine cranks

All fuses good
Neutral switch in neutral (closed)
Emergency Kill switch open

Seen that control wire for starter relay heads into the ECU for Air Fuel Mixture line (Measured continuity from relay coil to that line), although the schematic I am using has control of relay solely on ignition switch function.
Not sure where to go from here???

Help is appreciated.

So new motor never run.
Wired it up (had to buy adapter cable to compensate for old circular connector t the new square one)
Turned on ignition switch heard the 2 beeps oil and water temp LED lit for a bit (however the MIL nor Battery lights can on at any time). Checked wires seem okay.
Heard relays switch and high-pressure pump turn on for a few seconds
Heard starter solenoid click
And nothing more (no cranking)

New battery.
Disconnected starter solenoid enable wire, and jumped the solenoid terminal to +12 and engine cranks

All fuses good
Neutral switch in neutral (closed)
Emergency Kill switch open

Seen that control wire for starter relay heads into the ECU for Air Fuel Mixture line (Measured continuity from relay coil to that line), although the schematic I am using has control of relay solely on ignition switch function.
Not sure where to go from here???

Help is appreciated.
Paul, I had the same issue, brand new 150d motor with the adapter cable. It ended up being the key switch. For some reason the key switch on my 150a wouldn’t start the new motor. I happened to have another key switch that I changed out because the lights burned out and I hooked it up and the motor started right up! Going with a new key switch to the d series motors.
 
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