oil overfill

[2010kacey1]

2003,115 four stroke. After changing oil twice and using engine, the oil level reads overfilled on dipstick. Oil not milky, can gas get into crankcase? Engine runs and idles great. Also have the same problem on a 225 four stroke on boat with two engines, this only with one engine????

[E-Z]

Too much oil

One or both of your fuel pumps has developed a hole in the diafram. They mount on the back of the engine and work off a cam inside the engine. When this happens, it pumps gas into the crank case. I just ruined a Mercury 75 4 stroke becasue I didn't recognize it in time.

[2010kacey1]

Thanks EZ, I will disassemble the pump and check diaphram.

[robert graham]

Your 4 strokes may be "making oil', which has been an issue with some of these 4 stroke motors, where fuel finds it's way into the crankcase, causing an overfill condition. Do a forum search for "making oil" to read about this.

[2010kacey1]

Making oil

I disassambled the fuel pump and checked the diaphram, no problem there.
With all the post I have read today and talking to a Yamaha dealer mechanic, I think Yamaha needs to have a recall on engines with this problem. I dont think their is a fix for the problem other than changing oil after each trip which is crazy. Very dissappointed in Yamaha quality....

[E-Z]

making oil

Actually, it's near impossible to visually check the diaphram and find a problem. The fuel pump needs to be pressure checked while it's put togather. A tiny pin hole, invisable to the eye, will pump more gas than anyone could imagine.

[2010kacey1]

making oil

Ordered new fuel pump diaphram and oil change kit. I will respone back to this post in a few weeks to let you know if this effects the problem. thanks

[john100]

but seem to have trouble selecting reverse, when selecting it makes a grinding noise.
i have checked the gearcase oil and all is clean and ok.
could some body tell me how to adjust it or set it up