Motor Problem(Help Needed)
 

I have an old 1975 25 HP Johnson Outboard that is not running good.
It will run when it is idled up but at idle speed it has a bad miss and will kill.
I have cleaned the carb and diaphram, new plugs, new points and condenser. Changed the fuel lines, new tank and hose and bulb.
It has a lean/rich knob on the front .

Here is a picture of the lean/rich knob and a leak where the motor splits in half.

How do you set the lean/rich knob.(Tighten all the way and back out how many turns)?
Will the leak in this area cause the motor to run bad? Does it have a gasket in this area? Is it hard to fix?

The pictures didn't work the first time.

Usually these old motors have gas & have fire they'll run. If it has a bad miss may have a bad plug wire or fire jumping somewhere. Crank it in the dark & see if you see fire jumping.
As far as the lean/rich knob tighten then back out 1 1/2 turns & start from there.

As far as the leak that could be your miss also. If it's getting water in the heads it will crack the head or a piston. that needs to be fixed!

It dont miss a lick when running wot only when idleing and will kill.
There are small bubbles coming from the leak. Is this water or gas in this area?

its fuel and oil mix coming from this area, there is no gasket on this section of the motor just a type of putty like a hondabond or yamabond.
1 1/2 turns out on the screw will be a good starting point also check the timing base plate you may have to bump up the idle timing just a little to get it to run at idle..also double check your your points gap I believe on this motor its right around .018 to .020, chances are is the timing is a little to low at idle, make sure you dont mess with the WOT timing just idle timing you can easily melt a hole in the pistons..