Water in Oil with Good Compression Test

Ray Gill · Jul 22, 2013

My year old rebuilt '41 9N wouldn't start after sitting in field for a couple of weeks. Good spark and fuel and almost sounds like it wants to run but won't. Further research showed oil was overfilled and a greenish color. Removed air filter lower part and over a cup of water poured out. Also ran a dry compression test which was consistent 90PSI on all cylinders. I can clean up the filter and change the oil but what is the best order to handle these changes and how many times must the oil and filter be changed. It really has rained a lot in SC lately.

old · Jul 22, 2013

90psi on a year old rebuild sounds like something is bad wrong like a bad head gasket. If only a year old on a rebuild compression should be in the 125 or so if not higher.

Fuddy Duddy · Jul 23, 2013

Change the oil once and keep an eye on it. The green color may be antifreeze. 'Old' may be right about the head gasket. Who did the rebuild? Was the head and block checked for warpage and cracks?
But that wouldn't have anything to do with the low compression. Were new sleeves put in? Has it seen much use since it has been rebuilt? May be that it is just not broke in yet.
Hard starting could just be todays fuel. It can go bad in a short time. Always turn the fuel off while running and let the carburetor run dry if it's going to sit for a while. Also a good idea to use a fuel stabilizer.

Ray Gill · Jul 23, 2013

Thanks for your quick response OLD. I also would like a higher PSI reading but I also felt that there should be a difference in the cylinders if it were a head gasket. Am I incorrect in this thinking. With the water in the air filter could this not be condensation or the water got into the oil some other way since the radiator water is clean with no discoloration. The engine has always started and run well since the first crank up but I regretfully never did a compression check when I finished rebuilding it so I have no base number to go against. Any other tests to check on if the head gasket is bad. All the spark plugs look like they are running normal.

Ray Gill · Jul 23, 2013

Thanks Fuddy Duddy. I did the rebuild as I have done on all my classic car engines. The head was checked and replaced with a new one then rechecked also the deck was checked when the block was cleaned. I did have new sleeves installed by an experienced machine shop. The engine has approximately 7 hours on it. I will be using a fuel stabilizer in the future but I also only use ethanol free gas in all my carb engines. I also will follow your idea on running the carb dry since I haven't used the tractor much. Thanks for your insight.

old · Jul 23, 2013

If it has sat for say all winter yes it could well be condensation and water in the air cleaner is not good and can cause water in the oil. I would try an ATF treatment and see if your numbers go up.

Ray Gill · Jul 23, 2013

Thanks OLD and I will go with the ATF treatment. I hope it will help with the compression test numbers. It seems that many of the members do this and recommend this to engines that sit for a while as mine has, to help keep it fresh. Also I think I will get a new set of plugs if all goes well and after I change the oil and clean up the air filter. I'll post my findings.

old · Jul 23, 2013

Go with a set of auto lite 437 plugs if your getting new ones

Ray Gill · Jul 23, 2013

Thanks OLD, I use these now and will get new AL437s for the restart.

Water in Oil with Good Compression Test

Ray Gill

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old

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Ray Gill

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Ray Gill

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old

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old

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