outboards and oil

[dnej]

say, how does an outboard motor know that it is receiving the correct amount of oil in the fuel.
I am not talking about pre mix here.
David

[Noelm]

In a way it doesn't, there is a sensor/switch for low oil in the tank, similar for if the oil "pump" receives a signal that it should pump, there is various systems of course, simple carby models mix oil with the fuel at prescribed amounts, EFI types inject measured amounts into the engine itself, it's a bit more complex, but in simple terms, that's how it works.
edit, that should probably read DFI types!

[shaungonemad]

I reckon it would let you know pretty quick if it was getting the wrong amount.

[dnej]

shaungonemad, as in seizing up????????????
If there is no warning system in place, say a broken oil line,there would be a very expensive repair job.
I read where its not uncommon.
David

[shaungonemad]

shaungonemad, as in seizing up????????????
If there is no warning system in place, say a broken oil line,there would be a very expensive repair job.
I read where its not uncommon.
David

Yeah they don't go to well with out it.

[Noelm]

The oil system on 2 strokes works extremely well, you will read hundreds of stories about people who disconnect it "just in case" most actually over oil if they fail, of course there has been disasters, but so have there been similar in 4 strokes, like the 150 Yamaha that shreds a nylon gear in the balancer and blocks the oil pump, it's way too late before you know something has gone wrong. I would reckon there has been more motor damage by people forgetting to add oil when filling up than actual true oil system failures, plenty have problems and blame the oil system, particularly older OMC motors, but most are simply wrongly diagnosed.

[dnej]

Noelm, How does the motor over oil when the pump is broken. David

[Noelm]

Because it is a "pulse pump" driven by crankcase pressure change, via a diaphragm, if the diaphragm tears, the oil just leaks past it, instead of being regulated.

[Noelm]

I might add, that's for OMC motors, and they are the ones most often removed, it is a reliable system, but gets a lot of stuff written about how bad it is, Yamaha and Mercury go about it differently, but they are usually left on and operating.

[dnej]

Noelm, does the pump know if its not receiving oil?
David

[Noelm]

No, but it has a sensor in the oil container, so if there's oil in the container, it should be getting lubrication, the system was changed over the years to include various alert methods, unless you have some sort of really rare, undetectable fault (certainly possible) all the makers systems work very well, some later models (like the e-tec) can detect lack of oil, and automatically pump like mad to make sure you have oil, then if you ignore the buzzer, it goes into SAFE mode, if you continue to ignore that, well you're on your own! don't be fooled into thinking safe/limp/whatever mode is there to let you "limp" home, it is NOT, it's just another method telling you to stop now, or else, no oil, or a failed cooling system will stuff your motor in limp mode, nothing surer than that.

[dnej]

I was reading a good check to do, is mark the oil reservoir bottle, premix 20 litres in a portable tank at 50: 1, and go for a long run. Then check the level in the reservoir when you get home.
Great idea, would mean running on say 25 to one for that tank if the pump is working at the same time.
David.