A physical inspection might reveal cracks or leaks in the pump housing
Reinstall the lower unit bolts
check the Engine Compatibility table on this page
Inspect the spark plug and ignition coil terminals for corrosion or damage
Is this connector EPA and CARB compliant
Thermostat (143°F/62°C) – Fits Yamaha 2-Stroke Outboard 9.9-55 HP (Replaces 6F5-12411-01, 6F5-12411-02, 6F5-12411-03) GMC A physical inspection might revealProduct Details This replacement Thermostat (143F 62C) Fits Yamaha 2 Stroke Outboard 9. 9 55 HP ensures your engine operates at the correct temperature for optimal performance and longevity. It is engineered for a wide range of Yamaha 2 Stroke models from 9. 9 HP to 55 HP, specifically covering years 19861997 including series 9. 9, 15, C25, C30, C40, C55, CV25, CV30, CV40, and CV55. This part provides a direct interchange for Yamaha part numbers 6F5