Yamaha 61A-85790-01-00 – Thermosensor Assembly

Overheating can sneak up on any outboard, but this little sensor keeps things honest. The 61A-85790-01-00 threads neatly into the cylinder head and watches coolant temperature every second the engine is running, passing the info straight to your ECU and warning buzzer before heat can do real damage.

Why it earns a spot in your tool kit

1. True OEM pedigree – The Yamaha part number and tuning-fork logo are stamped into the 14 mm brass hex, guaranteeing a tight, factory seal.

2. Quick-reacting NTC core – The sensor’s nickel-tipped element lives inside a corrosion-resistant brass shell, so readings stay precise in salt or fresh water.

3. Plug-and-play lead – A waterproof two-pin connector snaps onto the stock harness—no wire cutting, no heat-shrink, no headaches.

4. Ready to install – Comes with a new Viton O-ring; grab a socket, give it five minutes, and you’re done.

Swap the thermosensor during your next tune-up and head back out knowing the gauge is truthful and the overheat alarm will speak up long before things get expensive. Small part, big insurance policy.

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  61A-85790-01-00, 61A-85790-01-00