yanmar gm30 f engine senders and switches

[julius222]

Hello All.

I have a Yanmar GM30F..with NO WIRING..its secondhand, delivered from the dealer without any wiring.

There are 4 senders/switches that I can see.

Top front of engine. There are no senders in the raw water but there are 2 (repeat TWO) senders in the coolant. One going into and the other comming out of the heat exchanger.

Question1. why 2 sensors? I guess that the one out of the heatexchanger (the hotter one) is the most important so I will use that

There is an oil pressure sensor down near the oil filter.

There is a switch at the back near the gearbox

Question 2: What the hell is this switch for???? it is a switch isn't it?? 2 spade terminals?

Help with these two unkowns would read with gratitude

Cheers

Julius
Darwin Australia.

[S/V Antares]

The sender on the back is likely the magnetic pick up /sender for the tachometer It is located on the top of the flywheel It counts the teeh as they zoom by (127 teeth on yours)