Yamaha alternative ways for reading out sensors?

I own a Yamaha 2-stroke from the 90's. This engine can be connected to a Yamaha 'marine meter', which has an alarm for oil and a bunch of other features such as an rpm meter. I'm wondering if it's possible to read these sensors manually and connect it to e.g. an LED or a third party rpm meter. Someone here who knows if this can be done?

 

Yes, just get the wiring diagram and you'll find the color code for each sensor.

 

Yamaha was the 1th manufacturer to use a proprietary bus system where all sensor outputs are multiplexed on the same wires. If your engine is equipped like that no 3rd party instruments can be connected.