Johnson Evinrude Outboard Motors 1956-1970 1.5-40hp repair manual., Page 140Get this manual
TYPE HI CARBURETOR ADJUSTMENTS
12- Mount the engine in test tank or
body of waterIf this is not possible, connect flush attachment and garden hose to the lower unitNEVER operate the engine above idle speed using the flush attachmentIf the engine is operated above idle speed with no load on the propeller, the engine could RUN-A-WAY resulting in serious damage or destruction of the unitCAUTION: Water must circulate through the lower unit to the engine any time the engine is run to prevent damage to the water pump in the lower unitJust five seconds without water will damage the water pumpStart the engine and allow it to warm to operating temperatureAdjust the lowspeed idle by turning the low-speed needle valve CLOCKWISE until the engine begins to misfire or the rpm drops noticeablyFrom this point, rotate the needle vavle COUNTERCLOCKWISE until the engine is operating at the highest rpmIf the engine coughs and operates as if the fuel is too lean, but the idle and high-speed adjustments have been correctly made, then recheck the synchronization between the fuel and ignition systemsOn engines with the flexible low-speed extension to the front of the engine, the spring maintains tension on the needle and adjustment will not be lost because of vibration during operationOn engines with the packing nut arrangement, the nut must be