2007 25hp Merc 4 stroke shutting off issue

[AC2717]

Hi Guys/gals, I have a 2007 Mercury 25hp EFI 4 stroke serial number: 0R181035 Feb 2007 F25ELPT. The boat was having trouble starting and once started it would not shut down with the key, I have to use the kill switch to shut it down. I replaced the starter solinoid and that fixed the starting problem. and then I replaced the ignition thinking that would solved the problem of not shutting down when I turn the key off. That did not work. I still have to use the kill switch to shut it down.

Has this happened to anyone else before? Does anyone know what it is? Anyone know how to trouble shoot it if not.

On a side not the ground wire coming out of the ignition switch branched off to two wires, but mine only used one, so I terminated the extra branched off wire. I would not think this would have anything to do with it anyways but thought I would check.

Is there something(wiring or a relay) between the kill switch and the ignition switch that is failed. I know the engine side would have to be fine if the kill switch is killing the engine, unless that goes to some place different on the engine

thank you in advance, Tight Lines!

 

[Texasmark]

Nobody answered so I'll kick the rock down the road. On electronic ignition engines, the engine is stopped by killing the triggers. In remote control engines, at least back in the early 2000s, the control box had a black ground wire and a yellow with black striped engine kill wire. When the key was turned to the off position, the ground terminal of the switch was connected to the engine off terminal.

If you have a tiller, the same thing is probably there for the same reason. Don't know about your engine but my Mercs use CD Ignition modules connected directly to the high voltage lead to the spark plug.

There is an input connector to the CDI containing at least the following wires:
Ground: Black wire which routes back to the battery - terminal

Ignition Power: Switched battery + which is red with a purple stripe, or purple wire and the purple is added because solid red is raw battery voltage whereas the power to the CDI units is switched by the ignition switch requiring the purple designation.

Triggers: May be a single wire, may be daisy chained so you would have 2 wires, one with the trigger input and the second the trigger out to the other CDI(s). Not sure of the color on that one

Engine Kill: As mentioned above.

My first approach to that problem would be to pull the wiring connector to the CDI and get on the switched ground wire...aka kill wire with the key in the OFF position and the black ground wire. If you don't get a short on your ohmmeter...1 Ohm or less, either you have a broken (kill) wire or your switch is broken.

However you said that your kill lanyard will kill it. That puts the problem in the control box if the lanyard kill switch is attached to the box, and that to me would signal a bad switch.....my next move in troubleshooting.

 

[AC2717]

follow up - wire from ignition to kill switch was bad. I replaced it and the kill switch wires into the harness. Problem solved. Thank you for the knowledge that put me in the right direction. Now I have another problem going on with the engine.

Hi guys, I have a 2007 Mercury 25Hp EFI 4 stroke - serial#: 0R181035

When I am just reving the engine with just throttle (button pushed not in gear) it revs up nice and high and wants to scream at WOT (basically runs great) when I put it in gear and try to WOT it, the motor barely does about a quarter of what it does when it is not in gear at WOT.
Does anyone have any idea why this would happen? Is there something electrical when in gear like a Limp mode? Is it the load from the lower end unit? Also I had to have the lower unit rebuilt, would this have anything to do with it? gear ratio or anything under load

I am running stainless 10 inch diameter with a 11 pitch on it, I know the prop changes performance. The engine is guesstimating to not even get up to 1500rpms when in Gear with WOT and it is not bogging down or anything. it won't let itself go past that rpms

I have had the throttle linkage adjusted and checked and in gear and while just throttle, the throttle linkage moves to the same exact spot so it is not losing traveler distance when in gear
Thank you in advance for ideas