Re: 2000 Yamaha 150 Outboard Oiling Problem
there is a much easier way to troubleshoot the system, one is to learn how it works.
by your statement that the manual transfer wont work its down to several easy issues. you have lost the ground path from the remote tank to the engine block, Blue wire, you have lost 12+ supply at key on from the splice just aft of the 10 pin enine harness,brown wire, the pump is defective or the filter is stopped completly( clooged filter you will hear the pump run yet no oil will flow.
anytime the key is on the brown wire at the pump has 12V+, use your multimeter and check it from the bullet connector on the pump( these fail to so inspect them) to the engine block, then shift to the Ohms scale and test the ground path, run from the bullet connector at the pump(blue wire) to the tank side of the emergency switch connector, should have less than 1 ohm, then go to the block side and repeat, should have less than 1 Ohm with switch acuated. then go to the engine block, should have less than 1 ohm.
all the emergency switch does is manually complete the ground path for the pump run circuit.
tank filter re[placement is actually a yearly or every 200 hour maint action.