Ignition before chocking

[Chasingluna]

Hello fellow sailors,

Today I made the mistake of turning off the ignition before chocking the motor on my Volvo diesel 2020 engine.

I know it’s really bad to do so and it was a mistake.

The ignition was off probably for like 3 seconds then turn on again.

The motor was then chocked the proper way and turned on and ran well.

But have I done damage to the motor? How can one know if I have?

I heard it burns the diode, but I have not a lot of knowledge on the matter.

Thoughts???

Thank you!

[glenn.225]

I assume you mean pulling the fuel cut off by the term chocking. And that you have a small diesel.

Turning off the power switch before the fuel cut off in no way will hurt your engine. However, it may damage your alternator or other charging components.

I have inadvertently turned off the power switch with the engine running a couple of times with no damage, but I consider it luck.

Sent from my SM-A536W using Cruisers Sailing Forum mobile app

[jamhass]

For most installations, turning off the "ignition" cuts the field to the alternator, so no damage is likely to occur. It is disconnecting the load (battery) with the alternator running that damages the alternator. This can happen if you switch off the master battery switch(es) with the engine running. Some battery switches have a "make before break" design that helps avoid situation -- for example when switching between house and start batteries. This feature does NOT avoid damage if switching the batteries to "OFF".

[Chasingluna]

Ok ok, I’m a bit more calm after reading this. Is there a way to test or to know if the alternator has had any damage?

[Tupaia]

You will not have damaged your alternator. Start the engine again and make sure the red charging (alternator) light goes out.


Turning off the ignition on most modern diesels actually closes the fuel stop solenoid. See picture below. Once started a diesel engine does not require electrical connections to run. The only way to stop it is to cut the fuel supply either manually or electrically. The fact that the engine stopped when you turned the ignistion off means the fuel was cut off by the fuel stop solenoid



Cutting the main battery feed as stated above will interrupt the charging from the alternator that causes a spike that can damage the alternator.

[deblen]

Operator's Manual see page 34


https://najad.co.uk/wp-content/uploa...anual-1997.pdf


Workshop Manual
https://www.marinedieselbasics.com/w...kshop-2006.pdf
see page 72

[Chasingluna]

Thank you, I did and it seems alright! I appreciate the help.