Yamaha f115 2003 water or gas in oil

[angler0520]

My 2003 yamaha f115 oil is very milky and after a oil change the oil become higher and higher on the dip stick and becomes very milky i think it smells like fuel but i dont understand how it becomes milky if it is fuel. does anyone know how to tell if it is fuel or water and where could it be coming from and how to corect the problem.

 

[Woodnaut]

Re: Yamaha f115 2003 water or gas in oil

What is the RPM at WOT (wide open throttle)?

 

[SparkieBoat]

Re: Yamaha f115 2003 water or gas in oil

you also should check your t-stat, I almost guarantee you it is stuck open...pricey little bugger too. but get a new one, proper operating temp is very important with these motors.

 

[angler0520]

Re: Yamaha f115 2003 water or gas in oil

wot rpm is 5300

 

[angler0520]

Re: Yamaha f115 2003 water or gas in oil

i replaced the t-stat already it was stuck open

 

[99yam40]

Re: Yamaha f115 2003 water or gas in oil

milky oil sounds like water not gas

 

[angler0520]

Re: Yamaha f115 2003 water or gas in oil

Where could the water be coming from

 

[SparkieBoat]

Re: Yamaha f115 2003 water or gas in oil

WOT RPM is a little low...I have heard low that over propped motors can build up some condensation for some strange reason..You may want to consider dropping about 2 pitch sizes with a new prop. this would get it up into the 5600-5800- range and I have heard another person said this solved the water in oil issue for them. you also may want to try raising your motor first, this can help you in many ways and get your RPMs up some. If your prop starts ventilating then drop it down a hole until it stops.

 

[Woodnaut]

Re: Yamaha f115 2003 water or gas in oil

I have a 2006 F90. I put a new prop on that brought the WOT down to 5,100 RPM. The engine started "making oil" at that point. (Blowby causing unburned fuel in the oil.) I repropped and brought the WOT back up to 5,900 RPM and haven't had a problem since. Search "making oil" on this forum for more info.

 

[Triton II]

Re: Yamaha f115 2003 water or gas in oil

I agree with 99Yam40, this problem is most likely to be water rather than fuel. I suggest getting a compression test done as it's possible you got a blown head gasket.

TII

 

[NESAR]

Re: Yamaha f115 2003 water or gas in oil

I agree.

 

[angler0520]

Re: Yamaha f115 2003 water or gas in oil

I have done a compression check and everything is good. I have herd that the oil pump seals could leak water in is this true

 

[Triton II]

Re: Yamaha f115 2003 water or gas in oil

OK, the good compression test rules out the gasket not sealing between the cylinders and the cylinder head. However, it could be the gasket has failed between an oilway and a waterway. However, I'm not a tech so whether the oil pump seal can cause this problem is unknown to me. Sorry, you'll have to wait for someone with more knowledge... 99yam40 maybe? (He's over on the yamahaoutboardparts forum).

TII

 

[jeffersondodson561]

Re: Yamaha f115 2003 water or gas in oil

Probably is the oil pump. You will need to pull the PH. Good idea to take it to a reputable shop. I would change the oil and let the engine run on the flushette out of the water. This will eliminate any exterior water intrusion. If you have water in the oil after letting it run on the flushette the water is getting into the oil from the cooling system. I would replace all the gaskets #21, #9 as well as oil pump orings and seal just on principle.



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