Re: 1998 Mercury 150 oil pump rotation sensor location
Rotation sensor should be mounted on the end of the oil pump, which is on the port side of the motor, near the cyl block to front eng case parting line, right between the topmost and 2nd cyl.
The alarm module wiring should have one green wire that drops down the rear of the motor behind the ignition coils, connecting to only one coil. Remove this green wire from the coil but leave the other green wire on the coil, that second wire connects the coil to the switchbox.
