2016 VF250XA VMAX SHO leaking oil

[Caniac03]

My VMAX SHO is leaking oil from the water inlet? on the leading edge of the lower unit. The engine has about 36 hrs on it and both the upper and lower unit was serviced 3 months ago. The oil leak began after our last outing and the boat has not been out since. Thoughts on what the cause could be and suggestions are appreciated.

[pstephens46]

What type of oil? Motor or
lower unit? Lower unit oil STINKS.

[Caniac03]

It smells like gear oil but I’ll confirm tomorrow.

[99yam40]

If you think it is lower unit lube, you need to pull the drain plug to see if water comes out.
for it to come out the top the level has to be extra high due to water entering it

[Caniac03]

I confirmed that the oil that is leaking is gear oil. I pulled the oil level plug and oil immediately poured out...approximately 2 tablespoons. The gear oil was clear (not milky)and no air bubbles where present. It looked as if it was being poured out of the bottle. If in fact water is getting in an raising the oil level wouldn’t the oil and water mix making the oil appear milky? Where do you typically put oil in the lower unit? Again, thanks for the discussion. BTW, the engine is still under warranty so I’m not too concerned about any work that needs be done. I just would like to diagnose the problem before I send it for repair.

[TownsendsFJR1300]

As your under warranty, DO NOT remove the plug or the evidence of an issue is gone..


New oil is pumped in from the lowest drain plug (top plug out) till it trickles out the top.

Once up to level, the TOP plug is put back in, the pump tool removed from the LU and the drain plug and new washer is installed.

[pstephens46]

Take it to whatever warranty Yamaha mechanic. Tell them what you saw/smelled. They should pressure test the lower unit. Easy and quick. Nobody wants a leaking lower unit.

[99yam40]

just in case you did not know this already,
warranty will not cover fishing line around a prop shaft screwing up seals
but should cover just about anything else that causes water to get in I think.

I believe the gaskets on the drain/ fill and the level indicartor plug are suppose to be replaced every time they are pulled.

may not want to tell them yoou removed that plug.

water is heavier that oil so any water collected should be on the very bottom by drain plug if the water has not been mixed yet

[Caniac03]

Lower unit is no longer leaking oil but I will take it to
the dealer anyways. I’ll let you know what they find. Thanks for the help.

[TownsendsFJR1300]

As fishing line, if there, isn't covered, I'd pull the prop, remove any line and re-install the prop.

I wouldn't mention about removing the line..


A simple pressure test (and water coming out the drain plug) will tell if there's an issue..

[Caniac03]

Wow...can’t get the boat to the mechanic for three weeks. Busy time of the season I guess.

[Caniac03]

Finally...removed the lower unit drain plug and no water, only gear oil drained out. Replaced both plug gaskets and topped off the gear oil. No leak. Thanks to everyone for the guidance.