225TXRP: what is this sensor on head?

[carboncow]

Any idea what this temp sensor looking little guy is here in my photo? Our boat doesn't have a temp gauge and we think the high temp sensors are the two at the top of each head.

[carboncow]

Oh heck..why we are at it can you tell me what the one in the green is too? I cannot determine these in the parts diagrams.

[boscoe99]

Knock sensor on the right and thermosensor on the left.

Most every part used on your motor is in the applicable parts catalog.

1991 225TLRP Yamaha Outboard ELECTRIC PARTS 3 Diagram and Parts

[carboncow]

What is the thermos sir as compared to the high temp sensors. Is it feeding the CDI specific temp info? Is it used for temp gauges?

[rodbolt17]

dude
buy a clue here shortly.

your motor has two overtemp SWITCHES.

one COOLENT temp SENSOR.

one KNOCK sensor.

its a basic stupid motor.

always look at is it a switch, on or off, or a sensor.