9.9 merc 4-sstroke question

[Guest]

I've got a 9.9 merc four stroke '97 that I bought new,and use exclusivly for slow trolling (idle speed).After a couple of seasons I noticed I get gas in the cankcase oil.I had it in for service a couple of times. The compression checks fine,and they can find no mechanical problems with it. They say because Irun it at idle speed exclusivley that some gas get unburned. I have pretty low hours on it,and I've taken it to different dealers.So I just change the oil a couple of times a season to maintain viscosity. And I get the same explanation at each dealer. Is anyone familiar with this problem? Or does anyone have a different opinion? The dealers say 4-strokes aren't desinged to maintain prolonged/ exclusive idle speed. Thanks for any info

[Guest]

bump

[Hookmaster]

The F115 Yamaha (4-stroke) has had issues with "making oil", i.e. gas getting into the oil. The reason was the break-in procedure in the manual wasn't sufficient in seating the rings. The fix is to, after normal break-in, to run at about 3/4 throttle for 2-3 hours. Some people have suggested running the Ring Free shock treatment (carbon preventer/decarbonizer) at the same time to help get rid of any carbon that has built up. This has been discussed a lot on Walleye Central's HSOforum on the Boat and Motor message board.

[Guest]

Hi Hookmaster,
What is the Walleye Central HSOforum address? Also what is Ring free shock treatment. If you can't give me that web address due to regulations please e-mail at
[email protected]

I would be most grateful.I'm glad I'm not the only one with this problem.When I drain the oil it not only has the odor of gas but also has some black sediment(carbon?} in it.
Is that similar to what others are experiencing on the Boat and Motor message board?
Thanks for your reply,
Jack

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serenity Jack