Gas leaking into oil F115 4 stroke

[Capt Dennis]

I have a yamaha F115 4 stroke 2004 with 255 hours <br /> It seemes to be leaking fuel into the oil crank case.The dealer decarbonized the engine and after 10 hours the oil level is 3 inches above the full mark.Any suggestions??

 

[WillyBWright]

Re: Gas leaking into oil F115 4 stroke

Welcome to iboats and have a look here. You're not alone. It's fairly universal among 4-stroke outboards. Some more than others. Making Oil<br /><br />There's no way around it, you have to reverse your way of thinking. Don't fill it. Allow room for it to grow. Only fill it halfway up the dipstick and change it when it's full. The oil isn't going to go down unless there's something seriously wrong.

 

[bossee]

Re: Gas leaking into oil F115 4 stroke

Yes,<br />What WillyBWright said.<br />I have a Yamaha F115 4-stroke (2003) and if you fill up to half of crosshatched area on the dip stick You should be fine until next oilchange (if You change every season). At least this works just fine for me.<br /><br />You may also read this Yamaha document for correct way of cheking oil level:<br /><br />

 

[rodbolt]

Re: Gas leaking into oil F115 4 stroke

run it and run it hard, you need at least 30 min above 4700 every time you take it out.<br /> biggest issue we have with 4 strokes is folks baby them.<br />its a very durable machine, maintain it and dog it,<br /> you will find it loves it.<br />that motor is very happy at 5000 RPM and will do it for thousands of hours.<br /> biggest issue we have is over propping/lugging. they will make oil if over propped or lugged.

 

[bossee]

Re: Gas leaking into oil F115 4 stroke

Hi,<br />That Yamaha document is going to show up when the server where I have the document is less busy. I have seen this problem before.

 

[jjenkins]

Re: Gas leaking into oil F115 4 stroke

thanks for the help and info