Oil leaks from 250 hp engine

[afisher3]

My port engine on my Jupiter leaks oil (about 3 ozs. after a 4 hour run) onto the swim platform when I raise the engine out of the water. Looking under the cover, there is no obvious source of the oil leak. I have heard the oil may be coming from the blowby tube. The starboard engine does not leak. Any suggestions where else to look? Thanks.

[boats.net]

Don't know what model engine you have but if leaking that much you should be able to get some idea where it is leaking.

[fhamilton]

I have the same issue

I have 3 x 2005 f250s on my Grady White and have the same issue with my starboard motor - a cup or so of oil on my transom. This only happens when the motor is raised and appears much worse when the motor is tilted to towards port. I found the oil is running down the flexible black tube between the motor and the transom and leaking out where the gas line Ys into the tube. I cannot find any obvious leak(s) inside but there is clearly a this layer oil inside the motor leading up to the tube.

Today I cleaned up any oil inside the motor and put paper towels in various locations to try and determine the source. I will be back in a couple of days to check on the motors.

I've heard about the blowby tube and also the potential for oil coming out of the dipstick when tilted to the port. I do not have this issue on the other two motors whether they are tilted to the port or starboard.

Any other suggestions on locating the leak would be helpful.

[afisher3]

Yamaha's answer

Tuppens Marine invited the Yamaha Service rep in Florida to come and inspect my motor. No obvious source of oil leak except the oil blow by tube. The rep said some oil leaking is normal. Says my problem is not a problem. He cannot explain the nearly cup of oil that leaks unto the swim platform when the engines are up. Yamaha should be able to do better than this.

[fhamilton]

@afisher3 - Thanks for the feedback. I agree Yamaha can do better than this. I got the same type of response from a Certified Yamaha Master Mechanic. He basically said - you'd think these expensive motors wouldn't leak oil, but they do when they are fully tilted.

In my case I just recently purchased the boat. There was no indication at the time of any oil leaks. I even had a Yamaha Tech come out during the Survey and check all three motors - they passed with flying colors. The motors have approx. 740 hrs.

I first noticed the leak after I ran the boat for a couple of days before having a new bottom job at the marina. I noticed a small amount of oil on the transom when she was up on blocks, motors fully tilted. Since she was out of the water, I also had the local Yamaha guys perform a complete engine refresh (plugs, oil change, oil & fuel filters, water separators etc.).

One thing that I noticed the other day was the oil that was leaking was brown – not like the clean new oil in the motor. I read somewhere that an apparent oil leak can be caused when the oil filter is replaced. The oil spills down in the engine when the filter is removed and takes a while before it shows up as a leak when the motors are tilted up.

Sorry for the verbose response but I wanted to give you my history. I’ll let you know what I find when I get back up to the boat this weekend. Hopefully my paper towel traps will show where the oil is originating.