Fuel leaking 40 hp Evinrude 1968

Redwing4900

Petty Officer 3rd Class
Joined
Aug 21, 2012
Messages
82
Hello all...posted on this subject a month ago, and wanted to pass on some info, and to get some more advice. I had a lot of gas/oil "bubbles" while motor ran In the water...but ran perfectly. Found out that it was because I was running a long shaft and the transom cutout was only 15"...meaning that it should have been a short shaft. Once I changed it to a shorter shaft the bubbles stopped, but this other issue won't go away. When the boat sits for a while with the motor locked up out of the water, a cloud of fuel forms around my boat. Why would this happen? I know that these older motors are not as efficient in burning the fuel, but do you think I can stop this problem? If not, I will get something newer. I have de-carbed the motor, and was considering taking the head off and cleaning the pistons and rings manually--even changing the rings to give me better compression...do you think that would solve anything? My compression readings are 115 on both cylinders, and I have cleaned my fuel bleeder valve. I think that I have ruled everything out. I realize that I can't make a 1968 a 2000 model, I was just hoping to save this old motor, like I said it runs smoothly and the electric shift works well too. I have changed the fuel filter, I also was disconnecting the fuel from the tank until the motor ran out of fuel thinking that might help too...it didn't. I wouldn't worry so much if I trailered this boat, but I park it for months at a time in the water. Any advice or wisdom would be helpful. Thank you.
 

Georgesalmon

Lieutenant Commander
Joined
Apr 14, 2012
Messages
1,793
Re: Fuel leaking 40 hp Evinrude 1968

The oil in the gas if 2 stroke doesn't all burn. I think that's what your seeing. One drop of oil will make a very large slick. Even a new two stroke will have this issue.
 

Redwing4900

Petty Officer 3rd Class
Joined
Aug 21, 2012
Messages
82
Re: Fuel leaking 40 hp Evinrude 1968

Thank you for your response...I took the motor apart today and found a broken piston ring the center one...I plan to replace it soon and can only hope my issue is because of that bad ring. I will let you know.
 
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