16CLEANING OF FUEL FILTERWARNING: INFLAMMABLES STRICTLY PROHIBITEDInterval of Cleaning and Inspection: Monthly (every 50 operating hours)Suction head in the fuel tankThe fuel filter (1) of the suction head is used to filter the fuel required by the–carburetor.A periodical visual inspection of the fuel filter is to be conducted. For that–purpose open the tank cap, use a wire hook and pull out the suction headthrough the tank opening. Filters found to have hardened, been polluted orclogged up are to be replaced.Insufficient fuel supply can result in the admissible maximum speed being–exceeded. It is therefore important to replace the fuel filter at least quarterly toensure satisfactory fuel supply to the carburetor.REPLACEMENT OF FUEL PIPECAUTION: INFLAMMABLES STRICTLY PROHIBITEDInterval of Cleaning and Inspection: Daily (every 10 operating hours)Replacement: Annually (every 200 operating hours)Replace the fuel pipe every year, regardless of operating frequency. Fuelleakage may lead to fire.If any leakage is detected during inspection, replace the fuel pipe immediately.INSPECTION OF BOLTS, NUTS AND SCREWSRetighten loose bolts, nuts, etc.–Check for fuel and oil leakage.–Replace damaged parts with new ones for safety operation.–CLEANING OF PARTSKeep the engine always clean.–Keep the cylinder fins free of dust or dirt. Dust or dirt adhering to the fins will–cause piston seizure.0.7 mm - 0.8 mm(0.028” - 0.032”)CHECKING THE SPARK PLUGOnly use the supplied universal wrench to remove or to install the spark plug.–The gap between the two electrodes of the spark plug should be 0.7 - 0.8 mm–(0.028” - 0.032”). If the gap is too wide or too narrow, adjust it. If the sparkplug is clogged or contaminated, clean it thoroughly or replace it.CAUTION: Never touch the spark plug connector while the engine isrunning (danger of high voltage electric shock).REPLACEMENT OF GASKETS AND PACKINGSIn reassembling after the engine is dismounted, be sure to replace the gaskets and packings with new ones.Any maintenance of adjustment work that is not included and described in this manual is only to be performed by Authorized Service Agents.Fuel pipeHose clampFuel filter (1)Fuel pipe