low oil level in engine tank

[Robert Hutchinson]

I have an old (1991) Yamaha 150 pro v that has been a great motor but now have a problem. When I took the boat out recently I got a low oil alarm and the engine rpms dropped. I killed the motor and found the oil level in the engine-mounted tank was at the low mark. I filled the tank with the toggle switch on the rear of the motor and temporarily corrected the problem. However, the oil level in this tank dropped below the low mark again when the engine was run a few minutes and the oil level in the boat tank was almost full. So, I replaced the oil level gauge assembly and strainer in the engine-mounted tank. This did not correct the problem with low oil level in the engine-mounted tank. Also, the oil level indicator on the dash is pointed to yellow. In summary, the oil pump works with the emergency toggle switch, I replaced the oil level gauge assembly in the engine oil tank and the engine tank still does not fill from the main oil tank when the engine is running in tilt down position. The yellow oil indicator on the dash is on. Any help will be appreciated.

Bob

[99yam40]

I think the yellow indicates the remote tank is low , so I would be looking at that float switch and/or the wiring.

[Robert Hutchinson]

I think the yellow indicates the remote tank is low , so I would be looking at that float switch and/or the wiring.

Thanks, If the level switch in the remote tank is bad would this prevent the pump from transferring oil to the engine-mounted tank? Is there a way to check the switch in the remote tank?

[99yam40]

The switch is on or off.
Closed or open
test with ohm meter
Service manual should have testing procedures

If oil module thinks level is low auto transfer does not work but the manual switch does

[boscoe99]

Thanks, If the level switch in the remote tank is bad would this prevent the pump from transferring oil to the engine-mounted tank? Is there a way to check the switch in the remote tank?

If the remote tank is low on oil the float will be down, and auto transfer of oil will be stopped. Some oil will remain for manual transfer. Maybe about two main tanks worth.

The float being low will turn on the yellow light.

A failed switch, a poor electrical connection, or a broken wire to the remote tank float switch will turn on the lamp and terminate auto oil transfer.

A digital meter set on the continuity function can be used to test the float switch. Up is closed and down is open.

[Robert Hutchinson]

Thank you boscoe99 and 99yam40. The remote oil tank float switch tested bad with a continuity check. To confirm that this was the problem I cut and spliced the two short wires (black and black with red stripe) going to the float switch. With the key in the "on" position the pump now delivers oil to the engine tank until it is filled. I also have a green light on the dash oil level gauge, however, I realize that this gauge is no longer working properly since I bypassed the float switch. I will order a new remote tank float switch and this should correct the oil transfer problem and allow my gauges to function properly. Thanks again for the great information!!!

Bob