Dial your Suzuki back to factory-fresh cooling precision with the Thermostat 17670-90J21. Tuned to crack at 50 °C (140 °F), this OEM brass-cup stat keeps DF150, DF175, DF200, and DF225 four-strokes running warm enough for clean combustion yet cool enough for heavy trolling on steamy summer days.

Why the genuine thermostat belongs in your 100-hour kit

• Precision wax-pellet capsule snaps open within ±2 °C of spec—no sloppy temp swings that foul plugs.

• Stainless frame & brass valve shrug off salt and scale; won’t seize like cheaper plated copies.

• Integrated bypass port trickles water during warm-up, preventing steam pockets at idle.

• Drop-in fit with factory O-ring groove—no trimming, RTV, or “universal” guesswork.

Swap it during your next impeller change: three bolts, old stat out, new one in, torque to spec. The payoff? Steadier gauge readings, quieter idle, and the confidence to hammer the throttle without eyeing the overheat horn. Small part, big peace of mind for every mile back to the dock.