2007-2009 Yamaha F15/F20 Outboard Service Manual, Page 270Get this manual
Troubleshooting the power unit Symptom 1: Limited engine speed (below 2,000 rmin) Symptom Buzzer comes on (remote control model) Overheat warning indicator comes on Cooling water does not discharge from the cooling water pilot hole Cause Clogged cooling water inlet Clogged cooling water passages Cooling water leakage Damaged water pipe or incorrect installation Water pump malfunction Cause Checking step Check the cooling water inletsCheck the cooling water passagesRefer to page 3-7 3-7
Damaged water pump impeller Water leakage from water pump housing
Check the water pipe and its installationCheck the impellerCheck the Woodruff keyCheck the water pump housingCheck the insert cartridgeCheck the outer plate cartridge