Honda Outboards BF40A/BF50A Service Manual, Page 312Get this manual
BF40A-BF50A
2CARBURETOR SYNCHRONIZATION
CAUTION
[1] SEALING WASHER (3)
Running the outboard motor without sufficient cooling water will damage the water pump and overheat the engineBe sure that water flows from the cooling system indicator while the engine is runningIf not, stop the engine and determine the cause of the problem1) Remove the engine cover2) Remove the 10 mm plugs and sealing washers from the intake manifold of each cylinder3) Attach the vacuum gauge adapters to each intake manifold plug hole and connect the vacuum gauge hoses to the adapters Connect: The No1 vacuum gauge hose to the No1 vacuum gauge adapterThe No.2 vacuum gauge hose to the No2 vacuum gauge adapterThe No3 vacuum gauge hose to the No3 vacuum gauge adapter4) Attach an engine tachometer and restart the engine Follow the tachometer manufacturer's instructions5) Run the outboard motor in an outboard test tank with the water at least inches above the antiventilation plateAllow the engine to warm up to normal operating temperature (Approx10 minutes) Is.rooLI