F-115 Yamaha 4 Stroke, Replaced T- stat and changed the oil. Went to the coast last week and put 10 hours on the motor, ran it fairly hard and used Yamaha Ring free with fuel additive. Checked the oil today and it is at the top of the hash marks. Put in 4.5 quarts when I changed it last week and the oil was half way between the hash marks. Any suggestions…???
you need to do a “carbon treatment”
and then if it still does it, almost sure its a fuel pump
I may be late in the conversation as it looks like this has been discussed before.
Are you certain you are getting gas in the oil and not simply different readings at different times?
Reason I ask is this…I had an F115 and depending on HOW I checked the oil I could get very different readings.
If I ran it on muffs to warm with the engine down, drained the oil, changed filter and refilled with 4.5 qts, restart it would show high.
However if I warmed it up, tilted up 45 degress, let it sit for 5 minutes, tilted the engine over for a few more minutes to help the filter drain, back down and drained then filled with 4.5 quarts I would get below the top of the hash marks.
Tilting up and letting it sit I found was the key to getting good readings and getting all the oil out when changing. Otherwise some must have been getting hung up somewhere then draining back down and showing high.
May not be your problem, but just make sure you are tilting up for a bit then back down to get consistent readings…before/after and intervals between oil changes.
Thanks for the suggestions, How do I do A Carbon Treatment???
186CC Key West 115 Yamaha
I have a 30, 4 stroke, and was told that leaving the fuel hose hooked up will cause gas to be drawn into the engine as it cools down. I take the gas line loose when I’m not using the boat and don’t get gas in the oil. It may be different in a larger engine, but it may be worth a try for you/
The question should be is this happening while he is running the motor or after it sits? If it is after it sis try unhooking hose after use and see what happens. whalked past my neighbors boat one day and smelt gas. Looked at the motor and could see gas dripping from the front of motor. Preesur had built up in his tank on this super hot day because the vent tube was partially clogged and was forcing the gas through the hose and carbs.