Finding 'Engine Live' DC power

[Papawads]

We happen to have a Yanmar 4JH3 engine in out 43DS, but I suspect this is a fairly generic question.

I'd like to find +12V within the engine compartment, which is only live when the engine is running. Will tap into this for an engine temperature gauge install (our boat doesn't have one).

Wasn't keen to come straight off the alternator output, even with a fuse (but should I worry?)

30 minutes with my head inside a French wiring diagram hasn't helped....

Thoughts most welcome.

Thanks

[GordMay]

12V ‘On’, when engine running, is available at the ignition switch, in the engine control panel.
It's usually fed to gauges [violet], via a fuse, then to sender [tan].

➥ https://www.cruisersforum.com/galler...=500&userid=79
➥ https://www.cruisersforum.com/forums....html#post2597

[knot smart]

i actually was just banging my head against the wall for several days trying to figure this out..

ok.. we have a DS43 with a 4JH3-TE that i just rebuilt and installed ..

over by a alternator there are a few wires connected between the alternator and the motor.. on the engine side of the wire harness is a red wire with black stripe .. this is the power from accessory key on position to power temp , oil gauges ... on our boat it is connected to a white wire tagged ALT2 that goes over to the battery isolator and it connects to the alternator as well