Keep your Mercury running at the sweet spot—not too hot, never too cold—with the 143 ° F Thermostat (833072003). Tuned to crack open at 143 ° F (62 ° C), this OEM part maintains the perfect operating temperature on mid-range 2-stroke and four-stroke Mercs from 75 hp through 125 hp, plus many classic inline-six “Tower of Power” models.

Why the genuine thermostat earns its place in your spring service kit

• Precision wax-pellet capsule opens within ±2 °F of spec, holding coolant temps steady for cleaner combustion and longer oil life.

• Stainless-steel frame & brass cup shrug off salt and scale that seize cheaper copycats.

• Laser-cut bypass port keeps a trickle of flow during warm-up, preventing steam pockets at idle.

• Drop-in fit with the factory O-ring groove—no trimming, no RTV.

Swap it when you change the impeller: three bolts off, old stat out, new one in, torque to spec. The payoff is quieter idle, steadier gauge readings, and the confidence to hammer the throttle without glancing back at the overheat alarm. One small part—season-long peace of mind on every run.