1988-1995 Mercury Force 5HP Outboards Service Manual, 90-823263 793, Page 14Get this manual
ACLEANING FUEL TANK 1Drain and flush fuel tank once year with fresh gasoline or solvent
NOTE: Flush more often, if required
BINSPECTING FUEL TANK CAP (1988A)
1Inspect cap gasket (A) for signs of cracking and replace, if necessaryInspect retaining ring (8) and anchor (C) for damage and replace, if necessaryInspect fuel cap (D) for cracks and replace, if necessary