Grayish Oily Foam

HeyGuy14

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Jan 13, 2013
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I bought a 99' Yamaha 115 2 Stroke, Model # S115TLRX a couple weeks ago from a family member. I have been working on the motor slowly. I changed the water pump/with repair kit. I changed the foot oil, new plugs and new thermostats. I was finally ready to try and crank it up. Yesterday it ran for about 10 to 15 minutes idling after trying to start it for awhile with no problems. It was sitting there for over a year in weather. Today, I cranked it up and grayish oily foam started to come out around propeller and out of center exhaust on propeller. I am now wondering if I screwed something up. There was no water in foot oil when I changed it out and the screws got new gaskets. So I am now scratching my head... I don?t know a ton about how 2 strokes operate. Any help would be much appreciated.
 

HeyGuy14

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Jan 13, 2013
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Re: Grayish Oily Foam

Also on a side note of more information. I did have a difficult time starting it and choked it a lot and used high idle a lot.
 

Grub54891

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Jun 17, 2012
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Re: Grayish Oily Foam

Well I hope you had it hooked to water,muffs or barrel.If not you smoked the impeller. Some residual oil mixed with the water is normal on muffs, however how rich are you mixing the oil? Or were you only able to run it with choke and high Idle? That would cause what you see at the prop. More info would be great.
Grub
 

HeyGuy14

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Jan 13, 2013
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Re: Grayish Oily Foam

1.)I definitely had it hooked up to muffs, the duel ones that feed both sides of intake.

2.) I am using the onboard oil tank to pump the oil from center console of boat. So not exactly sure if it is pumping correct amount, rich/lean.

3.) Yesterday we had to use both choke and high idle to get it started. After it started I eased off the choke and left it in almost a mid idle and it began to run good. Sounded great. Today, I only tried for a few try's both using choke and high idle and it started, but soon almost choked itself out and then it started oozing the oily foam stuff from around base of propeller to out the end of the propeller. After I tried cranking once again as once as it cranked up and accellerated it started spitting the oily foam out almost like a snot rocket or something (sorry thats gross). I decided I better not go any farther without some other opinions.

Hope the additional info helps. Thanks so much again.
 

Grub54891

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Jun 17, 2012
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6,173
Re: Grayish Oily Foam

I think you need to go through the carbs,if you need to choke it after startup just to keep it running it will be running rich and causing the ooze you see.
 

HeyGuy14

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Jan 13, 2013
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Re: Grayish Oily Foam

I sprayed carb cleaner into the intake ports on carb this morning and let them sit for about an hour. I did try to crank it again and it cranked right up but as soon as it smoked out the carb cleaner it stalled. I cranked it up again and it would only run with choke and high idle. I was trying to push choke back in and it would stall out, but right before I let it stall i would pull out the choke and it would fire right back up and run pretty good besides a little white smoke. It felt like I was controlling throttle with choke. While I was doing this it was in high idle. It wont run in just regular idle with no choke. Odd thing was today there was no more foamy oily liquid.
 

robert graham

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Apr 16, 2009
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6,908
Re: Grayish Oily Foam

Sounds like you need to have the carbs cleaned and set...the choke is just overcoming a very lean mixture caused by plugged jets. Add a fuel/water separator type filter and a fuel stabilizer like Stabil or Seafoam to help prevent these plugged jets...Good Luck!
 

HeyGuy14

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Jan 13, 2013
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Re: Grayish Oily Foam

I don't think it does, it ran for like 10 minutes. A couple days ago. So I am leaning towards the carbs need a major cleaning. Taking it to local mechanic Tuesday.
 

HeyGuy14

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Jan 13, 2013
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Re: Grayish Oily Foam

I did install a new water fuel separator filter and did put the marine grade stabil in the new fuel.
 
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