Bendix Engaging while motor is running

[RoughThumbBG]

Motor is a 2012 ProXS 225 HP. serial number 1B883693

I had a strange issue this past weekend when using my boat. I noticed a sound when shutting my motor down that was kind of like a whine of something spinning. After taking my cowling off to look I noticed that my started Bendix was staying engaged to the fly wheel when the motor was idling in neutral and the sound I heard was the bendix dropping down and spinning for a moment when I shut the motor down.

When I shifted into gear, either forward or reverse it would drop down as normal, but when I shifted back into neutral it would hop up and engage on the fly wheel and spin. It did this several times when testing, but then stopped and I didn't notice it again the rest of the day.

Any idea what could cause the bendix to jump up when shifting to idle? Is it an electric solenoid that causes this? Maybe I need to grease the started shaft? I am really hoping that its not an electrical component going out causing the solenoid to engage.

[lpugh]

You have two solenoids on this. One is starter mounted that does the heavy work and one the slave solenoid is mounted on the starboard side of the motor. There is a yellow/red wire that attaches to the slave that excites it that closes a circuit to provide higher amperage to another yellow/red wire that feeds the starter mounted solonoid which lifts the starter drive as well as provides current to the starter motor for cranking. Check for voltage on the Y/R wire at the starter motor solenoid while it is failing. There should be no voltage at that location unless you are cranking the motor. If you disconnect that wire the drive should drop and the motor will not crank. I suspect there will a voltage there of less than about 9 volts, if there is voltage at that locations. go to the other Y/R wire on the slave solenoid and check for voltage. This wire receives voltage from the key/start switch only on demand of cranking the motor. If there is voltage here you have a cross short to voltage some where such as switch or harness
This should give you enough information to narrow this down
Possible causes include:
Cross short
starter switch
Slave solenoid
starter solenoid
Since it drops when in gear I would think the problem would be between the neutral safety switch and including the starter switch

[OldTimer57]

I have seen more cases where the bendix has simply failed and stuck in position. Anything from a bad bushing to gunk, etc. My old hemi roadrunner would do this with some frequency. Got to be quite good at disassembly and repair rather than replacing.

[lpugh]

I have seen more cases where the bendix has simply failed and stuck in position. Anything from a bad bushing to gunk, etc. My old hemi roadrunner would do this with some frequency. Got to be quite good at disassembly and repair rather than replacing.

Totally different design than what Chrysler used, very unlikely to be a drive problem, very near impossible on this type of Mercury starter. Though I do know what you about those starters as well as a lot early Ford units

[EuropeanAM]

This is SIMPLE. Keyswitch is hanging in the START position.

That's why the starter would DISENGAGE when placed in GEAR (the neutral safety switch in the control is breaking the circuit).

Replace the keyswitch to resolve the problem.

[RoughThumbBG]

Thank you all for the input. I checked it this weekend and did find that the key switch would hang in the start position if I wasn't careful to ensure it set back into the run position. this would indeed keep the bendix engaged to the fly wheel.

Easy enough to keep from happening, but plan to replace the key switch to be safe.