Johnson 9.5 leaves oil slick in barrel after running

sledhead26

Seaman Apprentice
Joined
Sep 8, 2008
Messages
33
I been tuning on my 1970 9.5 and started noticing quite a bit of oil floating around in the barrel after i shut it down. Do you think this is caused by a bad lower crank seal? Any other suggestions?
 

schematic

Lieutenant Junior Grade
Joined
Jan 12, 2008
Messages
1,102
Re: Johnson 9.5 leaves oil slick in barrel after running

Welcome to the dirty world of 2-stroke. If it runs fine, its likely just unburned fuel. (normal)
 

sledhead26

Seaman Apprentice
Joined
Sep 8, 2008
Messages
33
Re: Johnson 9.5 leaves oil slick in barrel after running

Well is doesn't exactly run good. It surges on low idling an will only run on full choke. Put a carb kit in it and that didn't help. Figured it sucking air through the crank seals since it will only run on choke
 

tpenfield

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Staff member
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Jul 18, 2011
Messages
17,621
Re: Johnson 9.5 leaves oil slick in barrel after running

are you referring to the burned oil discharge from the engine. Brownish oily scum. . . that it what 2-strokes do. If you are talking about more of the rainbow oil slick, then it could be seals or just unburned fuel.
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
Re: Johnson 9.5 leaves oil slick in barrel after running

9.5hp motors always run like crap in a barrel because they sit right down there in the smoke. They need fresh, clean air to breathe. Stick your nose down in there and you will understand. However, that explains the surging but doesn't explain why you have to choke it. That strongly suggests a dirty high speed jet (orifice plug). Did you examine it carefully when you had the carburetor apart? Do you even realize it is in there?

Summing up, the barrel is fine for seeing if it will run, but you have to get it on a boat, on the lake, to tell anything about how well it runs. And yes, oily discharge is totally normal. People today just don't understand how it was back then.
 
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