Yamaha Oil system.

Working on the oil system and need to know how it works?????

The tank under the floor has an electric pump and a switch on it (motor) to feed when the tank on the motor when low.

Isin't it supposed to feed when the motor runs?

What sender sends a signal to the pump to feed the tank on the motor??

The tank(both) and lines were clogged with algae or white muck.
I cleaned them out and put in new oil(threw out the old) and flushed the lines.

Any literature on this??

This is the 3rd Yam in 1 year I've worked on with the oil algae growing in it.
I heard diesel fuel and some oils can grow algae or the sludge??

Thanks, Jerry

You'll have to respond back with your model/year for accurate answers to your questions. Yam engines have numerous different oil mechanisms. I'll try to answer what i can, but it might not apply to your engine.

Yes, the electric pump on the remote oil tank fills the engines main oil tank. It does this not only when the engine is running but also when ignition key is in ON position. On the engines main tank there are level marks. The remote tank senses when the main tank level is below the lowest mark and fills it. The oil harness is the sender, connected to main tank and reserve tank.

Im lost as to how anything would penetrate either the oil hose (containing oil) or the sender harness. The remote tank has a screw on cap that seals the tank. But if either are laying in a corrosive environment I suppose they could be penetrated.

Information about the oil system is contained in the service manual specific to your model/year. Unlike the owners manual, the service manual is purchased either online or at a yamaha dealer.

Sorry about the no model/year(rookie mistake)
2005 200hp. SX200TXRD
You pretty much answered my question.

The algae is from moisture(mold).

IF??? the boat sets for long periods and the condensation forms the oil grows mold/algae.

The mold is heavier than the oil and in the early stages it's small enough to go from one tank to another and then when the boat is used the oil is agitated and then it tries to flow and the build up flows into the pump and lines blocking it off.
The tank is full and can't tell it's blocked and POW engine failure.

No prob. I was hoping my previous response would be accurate to your model/year, not knowing the model/year. But yep, your engine uses the oil harness as the sender. And they ain't cheap either. And I now know more about algae then I could have hoped for. Good to know, thanks.

It's a pain cleaning them out but I'd suggest everyone check their tanks.