# Water in Oil - Where Can a Leak Down Test Pinpoint



## Silent Drifter (Apr 29, 2021)

Smackdaddy53 is one of the more knowledgeable engine guys im sure he will chime in directly 👍😎


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## Smackdaddy53 (Dec 31, 2012)

I’m just a shade tree mechanic that gets lucky now and then. @JC Designs is the Yamaha tech. 
To figure out if it’s water in the oil pour it in a clear glass jar and heat it up with a heat gun or something and the water will separate and sink to the bottom. You should see the layers if there’s enough water in it to turn it milky. If it’s gas it won’t separate and you’ll likely smell it. I think you have water seeping in through the crank case somewhere. I’m crazy when I tear into engines and if I tear down an outboard I’d nearly go 100% and rebuild with proper gaskets and components. James might have better advice but there’s mine.


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## eberin (Jul 11, 2018)

Smackdaddy53 said:


> I’m just a shade tree mechanic that gets lucky now and then. @JC Designs is the Yamaha tech.
> To figure out if it’s water in the oil pour it in a clear glass jar and heat it up with a heat gun or something and the water will separate and sink to the bottom. You should see the layers if there’s enough water in it to turn it milky. If it’s gas it won’t separate and you’ll likely smell it. I think you have water seeping in through the crank case somewhere. I’m crazy when I tear into engines and if I tear down an outboard I’d nearly go 100% and rebuild with proper gaskets and components. James might have better advice but there’s mine.


Have a jar already sitting on the bench too see.

Yeah at the age and issues of the motor, I’m ready to start looking internal myself, but I’m def browsing some catalogs.

If I have to sell for parts I might as well give it a go


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## Silent Drifter (Apr 29, 2021)

I think someones being modest🤔 JC may be the Yamaha man but i remember awhile back someone posted pictures of a beautiful diesel motor rebuild i thought it was Smack, it was surely done by someone with more than luck 👍😁


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## eberin (Jul 11, 2018)

Smackdaddy53 said:


> I’m just a shade tree mechanic that gets lucky now and then. @JC Designs is the Yamaha tech.
> To figure out if it’s water in the oil pour it in a clear glass jar and heat it up with a heat gun or something and the water will separate and sink to the bottom. You should see the layers if there’s enough water in it to turn it milky. If it’s gas it won’t separate and you’ll likely smell it. I think you have water seeping in through the crank case somewhere. I’m crazy when I tear into engines and if I tear down an outboard I’d nearly go 100% and rebuild with proper gaskets and components. James might have better advice but there’s mine.



Can a leak down test differentiate a leak from the power head gasket vs the cylinder head gasket? 

I assume it can't and you'll just find a leak out the cooling passages 

Granted if it's a cracked head, I'm assuming you could get a false positive. pass a leak down test but still have an internal issue in the block


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## JC Designs (Apr 5, 2020)

Silent Drifter said:


> I think someones being modest🤔 JC may be the Yamaha man but i remember awhile back someone posted pictures of a beautiful diesel motor rebuild i thought it was Smack, it was surely done by someone with more than luck 👍😁


Agree, Mac is a great mechanic and awesome rigger! My certs only give me the “cheat codes” lol!


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## Finsleft258 (Oct 7, 2018)

A leak down test can only be used reliably for verifying top-end (cylinder head) and piston/piston ring failure issues. 

As you've just had gaskets replaced, I would fully agree with the others that the problem is related to either the head gasket or base gasket. Fuel will not present as cloudy when it makes its way into the oil. 

Since you had broken bolts in the powerhead base, I'd be highly skeptical of the base gasket sealing surfaces. A leak down test could verify head sealing integrity and would eliminate that as a source.


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## Finsleft258 (Oct 7, 2018)

eberin said:


> Can a leak down test differentiate a leak from the power head gasket vs the cylinder head gasket?
> 
> I assume it can't and you'll just find a leak out the cooling passages
> 
> Granted if it's a cracked head, I'm assuming you could get a false positive. pass a leak down test but still have an internal issue in the block


A crack in the head passages will present noise throughout the water system and possibly enough pressure through the tell-tail (pisser) outlet. You'll know if it's cracked.


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## eberin (Jul 11, 2018)

Wow, took the skirt off and checked the of the power head bolts, the first one could almost finger loosen and all the others aren’t at the torque specs

hopefully that’s a sign


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## eberin (Jul 11, 2018)

That’s a negative ghost rider.


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## eberin (Jul 11, 2018)

Welp. Decided to pull the trigger on a Suzuki DF30

I’m going to keep this a a project motor to take apart and learn myself, maybe I can fix and resell

appreciate the help.

atleast I know the powerhead bolts aren’t stuck/break 😏


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## eberin (Jul 11, 2018)

Step 1 - don’t see any issues with the power head gasket but will order one regardless


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## Finsleft258 (Oct 7, 2018)

I do. They didn't remove all of the gasket sealant. That white line is residue from gasket sealant. It's not uniform which means the pressure isn't either. That white line to the right of the hose is old compared to the others. Also, the locating pin in the upper right is corroded and there is a lot of corrosion product build up around the exhaust passage. The O-ring below that exhaust port is flattened. That should have been replaced as well.


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## Finsleft258 (Oct 7, 2018)

I would bet the head job was similarly sub-optimal.


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