milky oil in four stroke 100 yamaha 2002

[jacklarge]

just noticed milky oil in my f100 yamaha. the motor runs good. Some say it smells like gas contamination but could be water? what is next step? drained the milky oil (salt water use) and filled with fresh oil. turn over twice a day without starting

[mommicked]

When my 03 F90 was making oil, the oil turned black and smelled strong of fuel.If its yellow or coffee w cream colored, Its probably water, but IM no expert.

[jacklarge]

the contaminated oil is now starting to separate; dark at top half and coffee and cream at bottom, is this water and what are the possible fixes? or problems? smells potent like fuel

[mommicked]

I would say its water, but how has the motor been maintained,? how long has the old oil been in there?What is the new oil doing? Are you saying the motor will not crank now? ("......without starting") ?

[jacklarge]

Motor runs great with slight sputter between 2500&3500 rpm. New oil contaminated in one day out. Noticed the water separator was full. Maintenance is questionable; just bought

[Woodnaut]

What is RPM at Wide Open Throttle? (Underway)

[cribber]

Milky oil is a blown seal of some type and water is getting into your oil. If it's your lower leg then you need to replace the seals at the least. If the milky oil is in the dipstick then you've got a blown gasket somewhere or a cracked block. Either way, it doesn't look good until you figure out where the water is getting into your oil.

[mommicked]

Is the new oil milky again, or stinks of gas?. If its milky, I would not run it anymore until you find out where the water is coming from and fix it, you may ruin the motor if you keep running it. Does steam or smoke come out of the exhaust or pisser? was there any oil sheen on the water around the motor?I would pull the sparkplugs and look for a wet or black one.If the plugs look good and dry, somethings leaking water into the crankcase, could be a gasket or a crack, and the motor will probably need to be dissasembled to fix it. I hope you got a great deal on it as it might cost alot. (But I'm no expert) just saying what I would do before taking it to one! I wish you luck.

[jacklarge]

number 4 cylinder had wet plug, others where burning good and dry. Compression on cold motor #1 cyl 140lb; #2 150lb: #3 130lb: #4 140lbs. Runs full throttle 5700-6000 rpms

[Woodnaut]

It appears that WOT is about where it should be, which would eliminate "making oil" due to over propping. A "making oil" scenario could possibly explain the fuel smell, but not the milky appearance of the oil. By the way, a leaking fuel pump diaphragm might also permit the passage of fuel into the crankcase.

[Smokey496]

The next step is to find the leak.

[jacklarge]

Thanks to all for your help. Now, to find the leak. I am trying to make a wise decision to pursue this mechanical endeavor further and spend more money or stop, get what I can, and buy new. Certainly, the biggest decision, which is all a crap shoot, is spending good money after bad.

At this moment, the compression (cold) is ok; tonight we looked at the zincs and the appeared ok (my novice theory is that the internal metal components do not have pinholes and electrolysis problems. However, there is ample corrosion (build up of crud assumed from lack of rinsing) Can lack of rinsing (and it's bi-product corrosiveness) cause deterioration and pinholes? therefore rendering the block and head useless. If not, then I deduce that a gasket is blown through, which is repairable. What exactly would/could the build up of non-rinsed, over time, crud do besides block orafaces. Can it also corrode (pinholes, etc) the inside of the engine to a point of non-repair?