I picked up an early 2000's Yamaha 9.9 4-stroke from an older gentleman. He indicated that it leaked engine oil out the exhaust badly after he attempted to replaced a cracked oil sump, and the aluminum plate that goes between the sump and powerhead. Everything looked to be assembled neatly, so I changed oil, fired it up in the barrel, and sure enough, smokey exhaust, and rapid brown creamy oil buildup in the barrel.
I've now pulled the powerhead, and this is what I see.
It looks like oil/water have been mixing. Before I go any further, I thought I'd check to see if anyone can offer guidance on the attempted repair process. I have a big box of gaskets that were included, many new OEM parts. I'm wondering if he forgot a gasket on assembly last time around? Is this oil sump cracking a common failure on these motors? Might there be some repair discusions documented somewhere? I've done some searching with no luck so far.
Any thoughts or guidance would be appreciated. Failing that, I'll stumble ahead with tools and shop manual at hand, and see what I can figure out!
I've now pulled the powerhead, and this is what I see.
It looks like oil/water have been mixing. Before I go any further, I thought I'd check to see if anyone can offer guidance on the attempted repair process. I have a big box of gaskets that were included, many new OEM parts. I'm wondering if he forgot a gasket on assembly last time around? Is this oil sump cracking a common failure on these motors? Might there be some repair discusions documented somewhere? I've done some searching with no luck so far.
Any thoughts or guidance would be appreciated. Failing that, I'll stumble ahead with tools and shop manual at hand, and see what I can figure out!