Peculiar Oil Leak on 1961 5.5Hp Johnson

[OptsyEagle]

So I tuned the motor up with new points, condensers, carb rebuild kit, new fuel lines, impeller, etc.

Anyway, the good news is that it runs great. Unfortunately, when I come back to the dock I have a small puddle of what looks like oil or oil and gas mix in the back of the motor, in the pan. The motor tilts back so any liquid would pool there. This liquid was there before I rebuilt the carb. I was hoping some new packing washers would stop the leak. It's about an ounce of liquid but since there is a hole there anymore would just drip out, so I cannot say how much is leaking.

Anyway, I figured it was my high speed needle leaking but I did a couple of tests. I put a paper towel below the high and slow speed needles and took it out and nothing dripped onto them, so I have to assume they are not leaking. Plus the motor runs fine and idles down very well. I then took a little of the substance and put it in a glass jar and put a lighter to it and it would not burn. It is greenish in colour so I assume it was oil mixed gas, however since it will not burn, I wonder if it is just 2 stroke oil or oil and exhaust water perhaps. However, if it was exhaust mix, I would assume the water and oil/gas would separate and it would also have a blacker color. This stuff doesn't. It kind of looks like just straight 2 stroke oil, with it's green tint.

I cannot see where it is coming from. There are traces of the substance on the sides of the pan and towards the carb area but the motor bounces around when running and a lot of that could come from the movement of the motor. I would assume most leaks in the carb, like the intake gasket and would create running issues.

Since it seems that it is mostly oil (not gas since it will not burn) I am wondering about the little tube that goes from the bottom of the powerhead up to the magneto plate area. I assume this is for lubrication but to be honest I do not know how it works. Would anyone know if straight oil lubrication moves up that area and if so, where it goes. I am perplexed because the only oil in this motor is the stuff I mix in my very combustible gas at 24:1.

 

[nwcove]

Re: Peculiar Oil Leak on 1961 5.5Hp Johnson

fuel oil mix is forced up that oil line to lube the upper crank bearing. sounds like your leak could be around the reed plate gaskets.

 

[OptsyEagle]

Re: Peculiar Oil Leak on 1961 5.5Hp Johnson

You know, you might be right. I would have thought that the motor would run rough if the reed gasket was not completely sealed but perhaps it's the manifold one, or maybe I am wrong. The liquid around the front of the motor, near those gaskets does have a sort of sprayed look to it, as opposed to a drip. Plus, any leak to the back of those gaskets has the liquid falling into the pan where there is an small elevated ledge (surrounding the base gasket) it would have to rise above to make it to the back of the pan, but the reed/manifold gaskets are before that ledge.

I am surprised that the liquid does not burn, since it must be gas/oil mix but perhaps the gas is evaporating quickly and just leaving mostly oil.

Anyway, I will take a closer look at those gaskets and see if I can tighten the screws for the reed/manifold. Probably hard to do with the carb still on it but I will give it a try. As I said, the motor runs well, it just makes this little mess in the pan so if I cannot get at those screws with the carb on it I may wait until I take it out for the season and remove the carb and maybe even change those gaskets.