The carburetor models' mechanical pump is a sealed unit that is non-rebuildable. It is positioned at the front on the right side of the engine. To remove the pump, you have to first disconnect the battery's earth cable and disconnect it from the circuit. After that, one can remove by loosening the fuel inlet hose, outlet line, and vapor return hose (if present). Take out two mounting bolts and take off fuel pump being careful to retrieve pushrod. Remove gasket and mounting plate and clean block mounting surface. To hold pushrod in position during installation, apply grease. Put new gasket, mounting plate and pump on block and tighten bolts securely. Securely connect inlet hose, outlet line as well as vapor return hose after that. When you reattach the hoses remember to properly tighten them. Finally, start up the engine to find out any possible leakage of fuel at any of these hose or line joints. For electric pumps in fuel injected models, perform a fuel pressure relief procedure and disconnect the battery cable. When removing it, mark properly for later reinstallation of fuel tank so as to reinstall it correctly later. This assembly is held to the fuel tank with a cam lock ring or snap-ring depending on model type. Take off this assembly from the tank cautiously while taking care not damage its float arm if possible. If needed change rubber gasket or O-ring and also check if necessary replace fuel strainer due to damage or clogs inside that filter screen element of this part of system assembly before reassembly process begins again in step 3 above but after first removing old one using hand tool like screwdriver handle perhaps before starting disassembling stage consisting putting new manufacturer's instructions specified machine into assembly for another such product purchased year ago installing company made spare component called mount mark 1 etc which come packed tightly within cardboard box having some tape seals across topsides open end where customer opens before starting. Therefore, remove assembly of fuel pump/sending unit into tank by aligning match-marks and snap-ring or cam lock ring lastly followed by assembly of fuel tank installation.