What is the yellow oil cap for back of 3YM30 Yanmar

[farmer.leo]

There is a yellow oil cap on the back of the Yanmar 3YM30, slightly
to the rear of the center axis of the saildrive. My engine is about a 2003
or 2004, and doesn't match the picture in the current operation manual.

Is this for the transmission, or the sail drive?

There is a label just forward which says 10w30. Is that specifically "gear oil 10w30"?

And if this is not the oil fill for the saildrive, where is that?

I'm attempting to put a photograph here. If it doesn't work, then
I've uploaded the same picture to my one public album.

 

[mitiempo]

Transmission I think.

 

[farmer.leo]

Transmission I think.

So that would be 10w30 "gear oil"?

And where does the sail drive get filled?
Is the sail drive only filled while out of the water?

 

[charles_reed]

On my 3YM20, which is basically the same engine, the additional filler goes into the timing-gear case.

I've assumed it's an alternative, perhaps easier to get to filler than the one on top of the rocker-box.

It certainly is no where near the gearbox.

 

[ostell]

On my 3YM20, I've assumed it's an alternative, perhaps easier to get to filler than the one on top of the rocker-box.

My installer told me that the filler caps you mention are indeed for easier filling.

The one on the leg is the dip stick for the gear box. The sail drive book is here. Looks like it specifies Mercruiser oil. Looks expensive, though perhaps your local dealer can tell you something different.

Some gear boxes take normal engine oil, perhaps this is the case here.

 

[testmonkey]

My installer told me that the filler caps you mention are indeed for easier filling.

The one on the leg is the dip stick for the gear box. The sail drive book is here. Looks like it specifies Mercruiser oil. Looks expensive, though perhaps your local dealer can tell you something different.

Some gear boxes take normal engine oil, perhaps this is the case here.

First make sure which gearbox you have, then check required oil type from here http://yanmarhelp.com/i_box2.htm
wrong oil will cause damage...

 

[Halo]

Looking at your picture I think that is the filler for your Saildrive. When you take out the plug does it have a built in dipstick?. I believe current practice is to use multigrade engine oil (same as your engine) for this.
Martin

 

[ostell]

Looking at your picture I think that is the filler for your Saildrive. When you take out the plug does it have a built in dipstick?. I believe current practice is to use multigrade engine oil (same as your engine) for this.
Martin

The booklet I quoted previously show the yellow cap as the dipstick. The booklet also shows the oil going in elsewhere. And the oil is given as a grade and then Gear Box oil.

 

[farmer.leo]

Looking at your picture I think that is the filler for your Saildrive. When you take out the plug does it have a built in dipstick?. I believe current practice is to use multigrade engine oil (same as your engine) for this.
Martin

Yes, there is a built in dipstick, but it is only about 2" long. Based upon the Sail Drive manual that TestMonkey awesomely put a link to, it definitely looks like the sail drive manual.

The sail drive manual says "use only" SAE 90. Can you tell me more about common practise? Like, how could I tell if the current oil is SAE 90 or the same oil in the engine (I think its 20w-40)?

 

[eagleswing]

trans dipstick..

when you are topping up the transmission oil with the same oil as your yan engine ie 10W30 or 20W40 , look at the line across the bottom of the trans dipstick. the oil should be up to that line when the dipstick is unscrewed and loosely resting in the fill opening. don't measure oil with the fill cap screwed in, and dont overfill the yans.

dont know about saildrives.. would not be surprised if the saildrive oil was 90 weight 'gear oil', same as most windlasses. check the site at boatdiesel.com for a lot of info on various yan engines.

 

[farmer.leo]

As per manual, and prior mechanic, use 80W-90 or 90W gear oil in for the sail drive.

Thanks again for the link to the SD20 manual.