2003 Johnson ST 55 HP WRL 2 Stroke Commercial Service Manual, PN 5005483, Page 105Get this manual
FUEL SYSTEM FUEL SYSTEM TESTS
Fuel Pump Pressure Test
Before testing, loosen fuel tank gas cap momentarily to release any pressureFuel tank must not be more than 30 in (76 cm) below fuel pumpRemove carburetor to fuel pump hoseConnect fuel pressure gauge between carburetor and fuel pumpInstall test prop
Primer Pump Test
STEP Start engine and allow it to reach normal operating temperatureSet engine speed at 2000 RPMWhile engine is running, operate the primer knob and observe engine speedTurn engine OFFResults: If outboard slows approximately 1000 RPM, primer circuit is functional If primer does not affect speed, proceed to STEP 2
STEP Remove primer hoses from fittings at top of carburetorsConnect 18 in1.0clear vinyl hose between each fitting and syringe, PIN 346936, filled with isopropyl alcoholPress lightly on the syringeResults: If fluid moves through passage, it is clearProceed to STEP If fluid does not move through passage(s), or excessive restriction exists, clean fitting with Cleaning Tool, PIN 326623, and retest