Mercury Force 9.9, 15HP Outboards Service Manual, Page 15Get this manual
DINSPECTING FUEL CAP AND GAUGE ASSEMBLY (PLASTIC TANK) 1Inspect cap gasket (A) for signs of cracking and replace if necessary2If parts other than the cap gasket
damaged, replace the complete cap
Remove gauge assembly (A) from fuel tankInspect gauge gasket (8) for signs of cracking and replace if necessaryInspect float (C) for damage and make sure it is not oil soaked
Inspect pick-up tube (with screen) (0) for damageIf parts other than the gauge gasket (8) are damagedreplace the complete gauge assembly