1978 Johnson 175, 200, 235 HP Outboard Service Manual, Page 36Get this manual
eIf the pressure is below 2-12 psi (17 kPa) with the gallon (22.7 litres) tank, stop the enginePressurize the fuel system with the primer bulbWhile holding the pressure, inspect the pumps, lines and fittings for fuel leakageReplace pumps and correct leaks as necessary and retestIf there are no leaks, replace one pump with new pump and repeat the wide open throttle testIf this results in the required pressure, the faulty pump has been replacedIf this does not result in the required pressure, the remaining pump is the faulty one 1Cover, washer, and screw 2Screen 3Gasket
CHECKINGCORRECTING BUILT-IN FUEL SYSTEMS Use #376156 fuel connector, #173245 primer bulb and no more than feet (1.8 m) of 14" I.Dflexible hose #321236 to connect the tank to the engineThese are the same parts included with OMC gallon (22.7 litres) tank supplied with engineIf the tank is located so that more than feet (1.8 m) of line is required, it must be at least 516" minimum I.Dbetween tank and primer bulbOMC #319719 flexible hose or 38" O.Dcopper tubing are satisfactoryAll fittings must be minimum of 14" I.DBe sure lines are free of kinks or sharp bends