F115 Water in Crankcase

[kkilloy]

Bought a used Yamaha 2001 F115 last week with 430 hours. It looks to be in good shape. I changed the water pump impeller, oil & filter right away. After I ran 10 hours I noticed oil on the outside lower half of the engine. I checked the oil level and oil was coming out of the dipstick hole. I drained the oil and got almost 6 quarts. Looked like water in the oil because it was milky colored. What is the best method to determine the source of the water. Compression test? Pressure test on cooling system if possible. One post mentioned the seal at the water pump, but I am not sure how this would cause water to get in the crankcase, but I removed the foot again to see if something looked out of place, nothing obvious. Thanks for any help in advance. This is a great forum!

 

[Yamajoe]

Re: F115 Water in Crankcase

A leakdown test will be best, but also do a compression test, and post your details, and be prepared to do some heavy work on your motor.

 

[kkilloy]

Re: F115 Water in Crankcase

I will do a compression test tonight and post results. I do not know how to do a leakdown test. Thank you for your reply.

 

[mdunn]

Re: F115 Water in Crankcase

I have the same motor and also found water to be in my oil.
Did a compression test and leak down test and everything is real tight.
Compression was 180 on all four and the leakdown test showed very small percent leakage on all four.
I change oil and put a new thermostat in.
Ran it for a couple hours the other day above 4000 rpm and didn't see any sign of water but I'm not convinced I've fixed anything yet.
See this thread http://forums.iboats.com/showthread.php?t=198532

And this one http://forums.iboats.com/showthread.php?t=141282

Here's a good disertation on leakdown tests.
http://www.xs11.com/tips/misc/misc3.shtml

I know I'm not helping much as I'm still trying to figure it out myself.
I'll be watching the thread.
Good luck.

 

[kkilloy]

Re: F115 Water in Crankcase

I did the compression test tonight and got the following. #1 being the top cylinder. I ran the test 3 times on each cylinder.

#1 = 160-170
#2 = 160-170
#3 = 160-170
#4 = 130-150

Could a blown head gasket be causing the water getting into the crankcase and the lower compression reading? Is there something else I can do to narrow it down?

Thanks again for the awesome help on the iboats forum.

 

[mdunn]

Re: F115 Water in Crankcase

Did you get any further on finding out where the water source was in your crankcase?
I've been out of town and not had much computer access.
I notice the links I posted didn't work automaticaly but if you cut and paste you can get there.
Did you read the last link I posted regarding doing a leakdowm test?
What I don't know and was hoping someone would comment on was is there a path the water can take between the water jacket somewhere and the crankace that a leakdown test on the cylinders wouldn't show.
I'm not convinced yet that I've solved the problem by just changing the thermostat although my oil looks good right now.

 

[kkilloy]

Re: F115 Water in Crankcase

I took the boat and the oil I drained out to the local Yamaha dealer. They said it was fuel and not water. The thermostat was stuck open and the engine was never getting to operating temp. The rings were not seating and I had one of the "making oil" situations. I should have looked closer at the oil to determine if it was water or fuel. I was very happy with the dealer repair. They installed a new thermostat, spark plugs and oil filter. Total parts and labor only $175.00. Very fair to me. Thanks again for all the help!

 

[mdunn]

Re: F115 Water in Crankcase

Glad it worked out for you.
Maybe mine was fuel too.

 

[Pas Bon]

Re: F115 Water in Crankcase

I took the boat and the oil I drained out to the local Yamaha dealer. They said it was fuel and not water. The thermostat was stuck open and the engine was never getting to operating temp. The rings were not seating and I had one of the "making oil" situations. I should have looked closer at the oil to determine if it was water or fuel. I was very happy with the dealer repair. They installed a new thermostat, spark plugs and oil filter. Total parts and labor only $175.00. Very fair to me. Thanks again for all the help!

That seems to be a very common problem with these Yamaha's

 

[AGENT 37]

Re: F115 Water in Crankcase

That's a lot better than the good ol F100 that I bought a year ago.... it was corroded through the water jacket to the oil on the cyl head and the oil sump. What a nightmare that was. I got it fixed though.