Question about neutral safety switch

[gcmarshall]

The following is from Selon Online -

"A neutral safety switch is installed on remote control models to permit operation of the starter motor only if the shift control lever is in neutral. When used, the switch is a safety device that prevents accidental engine starts when the motor is in gear."

I take it that the above only applies when the engine is not running?

Both of my engines, while running, if I was to turn the key to start, you will here the clang! as the pinion gear hits the rotating flywheel. (the problem I have as outlined in my other post, is that one of the engines does that with the engine running without playing with the keyswitch!)

[Garfish]

This happens intermittantly, on it's own?

[gcmarshall]

yup...it's the story of my life right now....

[SEAHORSE]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by gcmarshall &raquo;</TD></TR><TR><TD CLASS="quote">

Both of my engines, while running, if I was to turn the key to start, you will here the clang! as the pinion gear hits the rotating flywheel. (the problem I have as outlined in my other post, is that one of the engines does that with the engine running without playing with the keyswitch!)

</TD></TR></TABLE>


That's not good! Use a voltmeter and check for voltage on the yellow/red wire at the starter solenoid. There should be none when the motor is running, only when cranking over. There should not be any voltage on the starter B+ terminal either. If there is 12V, then you have to trace the wiring back to find out where the voltage source is coming from.

Also check the starter itself that the spring on the starterdrive is not broken which would allow the drive to bounce up and down, hitting the flywheel.

[gcmarshall]

Seahorse - don't think it would be a broken spring since the tachometer is jumping up at the same time that the starting motor is engaging....so it must be due to an electrical connection rather than a broken spring.

I will do as you suggest with the voltmeter...

[ssimpala71]

If there is voltage there you are only going to see it when the drive is trying to engage. Is it doing it dependably where you can "catch" it?

[jimh]

The neutral safety switch is typically wired in series with the 12-volt supply lead to the starter solenoid from the ignition switch. If the engine is in gear, and the engine is running, and you turned the key from RUN to START, the starter motor would not engage.

If your starter motor is engaging while the engine is running and the engine is in gear, you most likely have some other stray path of current which is supplying the solenoid.

The typical OMC or BRP ignition wiring is shown in

http://continuouswave.com/whal....html

--jimh

[gcmarshall]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ssimpala71 &raquo;</TD></TR><TR><TD CLASS="quote">If there is voltage there you are only going to see it when the drive is trying to engage. Is it doing it dependably where you can "catch" it?</TD></TR></TABLE>

No, it isn't unfortunately......it appears to be happening when the engine is operating at "high" rpms, say about 4000, and then when it is slowing down....but it really isn't anything consistent.

[gcmarshall]

Thanks! That link is most helpful!

I will have to check my other "good" engine to see if by turning the keyswitch if the starter motor will engage. I know that they won't engage with the engine in gear while it is off for sure.

This way I should be able to figure out if it was wired incorrectly from the beginning, or what exactly is happening.

Anyhow, as mentioned in my other post, I do know there is some problem in the wire harness, so will be ordering a replacement today, and hopefully replace that next weekend, and hopefully that will solve everything.

[gcmarshall]

Well, I replaced the wire harness this weekend and discovered that the old wire harness had a break in it and corrosion had got to some of the wires, most noticable the yellow/red wire which is used to engage the starting motor. This break occurred where the wire harness go through a hole in the transom of the boat to the engine. The fibreglass had worn the wire insulation off and eaten some of the wires. There was a plastic protective lining around them, but this must have come off somehow.

So, I am hopeful this has solved the problem on this engine.

Thanks to all who have provided assistance.

[gcmarshall]

I looked at the old harness a bit more last night.....what happened is the purple wire (Accessory wire providing 12V to the tachometer) corroded and broke, but was still held by the insulation....and the yellow/red starting motor wire was right next to the purple one and was open and badly corroded.

So it seems that...

tachometer not working was explained by the break in the purple wire.

the pinion gear striking the flywheel was caused by the purple and yellow/red wire rubbing together, especially when the boat was turning. This still happened regardless of if the engine was in gear or neutral because it bypasses the part of the circuit with the neutral safety switch

When the tachometer struck the flywheel, the tachometer would also come to life...I guess 12 volts would flow from the purple wire, to the yellow/red wire where it would both go back to the solenoid and engage the starting motor, as well as come forward, past the break in the purple wire, and jump back onto the purple wire, and supplying the tachometer with 12 volts...

;-)