Turning off ignition with engine running

[lumphammer]

If the ignition is turned off while the engine is running, what is the likely effect? The engine is a Sole diesel.



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[StugeronSteve]

This could well damage the alternator.

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[andyball]

If the alternator is machine sensed.....no effect at all: the alt. is still connected to the battery, the regulator gets its input from inside the alternator....no change. In fact this is exactly what happens (ie, nothing) when you turn off the ignition on most cars & trucks.

If battery sensed via the ignition switch so that the voltage drops to zero when turned off....you'd possibly get overcharging which would make the batteries gas a lot & might damage anything running from the batteries.....just as likely in my exp. that you'd get no charging until some voltage was present at the sense terninal.

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[boatmike]

Agreed. Most probable damage would be to diode bridge.

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[chriscallender]

Totally anecdotal evidence - I did it when I first got the new boat (too used to cars and forgot about the stop switch). No damage at all, which I assumed to be because the alternator is still connected to the batteries even with the ignition turned off. Or maybe I was just lucky. I certainly made sure I never did it again. That was on a Bukh 20hp if that makes any difference.

Chris

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[maxi]

Early Sole models had a built in switch dedicated to turning off the alternator - with the objective of delivering more power to the propeller for short periods - so I would expect it to be ok.

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