Yanmar 3YM30 Starter panel

[laforge24]

I have a Yanmar starter panel with key on-start, glow opposite direction,
and a Stopbutton,
Trying to solve a starter issue and can only lead it back to the
start switch ie: key
I want to try shortcutting at the back of the switch to see if the key
contact is working!!
any other suggestions maybe, because the starter turns, but not with the key??
we are trying to get back home in somewhat of a hurry, no good
mechanic availabe, probably no parts either,
any tips would be welcome, thanks
a sailor on the 'road'

[Roy M]

Start with checking the ignition switch. That's as far as I needed to go. Corrosion is the issue. I replaced the keyed switch with a Hella (supposedly) waterproof battery switch. The second one got packed with grease and has held up well. Since the ignition circuit is controlled by an interior selector switch, there is no need for the added security of a keyed switch. I built a custom panel, so I wasn't constrained by the geometry of the keyway.

[Dsanduril]

Here is the wiring diagram for the 3YM30 type B panel. The part numbers shown in the diagram are as follows:

1 – Alarm Lamps
2 – Buzzer Oil Pressure
3 – Coolant Temperature
4 – Sail Drive Seal
5 –Charge
6 – Fuse (3A)
7 – Stop Switch
8 – Diodes
9 –Key Switch
10 – Tachometer Hour Meter
11 – Instrument Panel
12 –Wire Harness Option L=3M
13 –Wire Harness Option L=6M
14 –Amplifier Only for Sail Drive
15 –Procured by Customer
16–Battery
17–Battery Switch
18 –Engine Stop Solenoid
19 –Relay
20 –Glow Plug
21–Stop Relay
22–Starter Relay
23–Starter
24 –Coolant Temperature Switch
25 –Engine Oil Pressure Switch
26–Alternator
27 –Ground
28 –Sail Drive (only for sail drive)
29 –Key Switch
30 –Coupler (view from A-A)

For the key switch it looks like connection #30 (red) is the +12V to the ignition circuits. Pins #G2 (Blue) and #17 (white) are energized at start. If you have already run the glow plugs using the glow position then you can probably start the engine without G2. So, if you can find a toggle switch (momentary/preferably spring return) you can take a wire from #30, through the toggle switch, to #17. That should allow you to start the engine and bypass the key. Anything you can do to make that connection is OK, the one thing you want to avoid is keeping that connection closed (and thus the starter running) once the engine has started. A spring-return or push-button switch, two wires you touch together, whatever will make that connection.