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

Your Yamaha’s powerhead can idle for hours or rip across open water at 5,000 rpm—so long as it stays in its comfort zone. This thermosensor is the small brass guardian that makes sure it does. Threaded into the cylinder head, it tracks coolant temperature in real time and relays data straight to the ECU and dash alarm. Lose it and you risk silent overheating; swap it in and you restore instant warnings and limp-home protection.

Why it belongs in your boat:

• Genuine Yamaha part number and tuning-fork logo laser-etched on the 14 mm hex for a leak-free, OEM fit
• Fast-response NTC element sealed inside a corrosion-proof brass body delivers accurate readings in salt or fresh water
• Waterproof two-pin plug snaps onto the factory harness—no splicing, no guessing
• Includes a fresh Viton O-ring for a five-minute install during your next spark-plug or anode change
• Built to Yamaha’s exacting standards, making it the smart swap whenever you see a flickering temperature gauge or hear the overheat alarm

Replace the sensor once and ride knowing your temperature gauge—and your engine—are exactly where they should be.