Oil on top of 9.9 driveshaft

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ba_50

Chief Petty Officer
Joined
Apr 4, 2001
Messages
635
This is a J10Rena 9.9 2-cycle and the top 4 inches of driveshaft is coated in oil and running down the shaft. It is also on the outside of the midsection.

Is the lower crankcase seal bad or just running to rich? It doesn't smell like gear oil. Thanks.
 

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raczekp1

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Re: Oil on top of 9.9 driveshaft

its unbarned oil from your mix.
maybe compresion is low and motor is not burning all amount of mix oil.
also under exhaust (under powehead, covered by mid section) is gasket.this gasket can be burned
 

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T

the machinist

Senior Chief Petty Officer
Joined
May 7, 2002
Messages
711
Re: Oil on top of 9.9 driveshaft

It appears that you have the upper thrust mounts bad which also take out the rubber grommet seal around the thrust mount arms. With these grommets bad, the unburned oil is forced out by exhaust pressure inside the exhaust housing, witnessed in your photo by all the black oil blown forward around the pivot shaft.

This is not a simple fix as the powerhead needs to be removed, & 2 new expensive upper thrust mounts & grommets. Many times the 2 thrust mount attachment bolts will be siezed in the exhaust housing.

For more detailed information on this go back to the FAQ section of this forum & down to my 9.9/15hp repairs link.

By the way I snatched your photo of the leaking oil & placed it on my Powerhead/Gearcase article where I describe this situation.
 
B

ba_50

Chief Petty Officer
Joined
Apr 4, 2001
Messages
635
Re: Oil on top of 9.9 driveshaft

I've been messing with this motor off and on for quite awhile. I saw the bill of sale from the guy I bought it from. He bought it new and used it about 3x as a kicker motor and it sat in the Florida sun all these years.

It worked ok for 20hrs than wouldn't power up and the full choke wouldn't start it. I put a new fuel pump kit, head gasket, and fuel pump on it. I've cleaned carbs for the last 15 years and until I worked on a couple off a 48hp Johnson did I realize how difficult it can be to get them clean after just idling or sitting for 2 years.

Anyhow, I tried running this motor for 2 miles above idle trying to clean it out. Hopefully that might be the only reason that oil, which is the same color of the 2 cycle oil I use was on the driveshaft. The car was soaked another 12 hours and a piece of wire was used to clean the holes. Then sea foam was run through it. It started using the choke twice. I haven't tested it on a boat yet to see if it has full power again.

I can't seem to locate my manual to see what you mean by the grommets. The exhaust side was taken off once so maybe it needs a new gasket to. The compression was ok unless the gauge was off.

I haven't been able to find your post yet on 9.9/15'ssample 011.JPGsample 011.JPG.

Machinist, here is a picture of what happens when a square fuel pump goes bad. Maybe you can use it. Thanks.
 
B

ba_50

Chief Petty Officer
Joined
Apr 4, 2001
Messages
635
Re: Oil on top of 9.9 driveshaft

It doesn't sound like it should affect the motor operation, it just leaks either through the housing gasket or the upper thrust mount somehow. Guess I need to make sure the power problem is solved first.

I once took the block off an '85 8hp to get at the water tube washer and it wasn't too big a deal.

Machinist, I couldn't find your information through the FAQ's so I checked your posts and will assume that is what you were talking about.

Thank you both for the information.
 
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