2003 Polaris MSX 140 Personal Watercraft Service Manual, Page 29Get this manual
Maintenance EngineContinued ThermostatPop Off Valve Cleaning
If low end performance of the watercraft begins to deteriorate, and the jet pump intake area is free of debris and weeds; or if the overheat alarm sounds, the thermostat pop off assembly should be checked for debris and cleanedInspect the thermostat pop off assembly if the watercraft has been stored for more than 30 days or has been used in salt waterCAUTION: Note the location of all parts when cleaning the thermostatpopoff valve assemblyBe sure all parts are positioned correctly during reassembly, or severe engine damage will result within very short period of operationDo not perform this maintenance while the watercraft is in the waterThe thermostat pop off assembly is under tension from an internal springWhen the screws are removed, the assembly will come apart quickly if not held together firmly1Using 316 (.5 cm) hexagonal wrench and flat screwdriver, remove screws while holding thermostat pop off assembly firmly togetherCarefully take assembly apartBe careful not to lose any parts2Inspect thermostat pop off assembly for debris, such as sand or seaweed, and clean thoroughly with waterInspect pop off valve for wearSee Ill13Inspect condition of gaskets and rubber partsReplace any parts that appear cracked, damaged, or distorted4Inspect thermostat and housing for corrosionVisually inspect thermostat for damage or distortionIt should be closed at room temperature5Apply Loctite 242 (Blue) to boltsCarefully assemble thermostat pop off assembly in the correct sequenceIt is recommended to hold the assembly in one hand and hand tighten screwsVerify proper alignment of all parts and gasketO-ring during assemblyThe arrow in the illustration indicates the direction of water flow (away from engine)See Ill2WARNING: If popoff spring or thermostat are mis-aligned during assembly, severe engine damage may occurIll1 Thermostat Pop Off Valve