The 8N has been doing some work around the yard. I traded an old straight pipe which ran under the tractor for one that aims up. The tractor had a minor miss on one cylinder which got much worse the more I ran it. I have been testing additives just to see if they have any effect on it (I expect they wouldn't but the tractor seemed like a perfect test subject since I am rebuilding it soon).
The first additive I tried was SeaFoam. Since it only took half the can to treat the oil, I used the rest to treat the gas. It did not solve the miss and the tractor continued to smoke the same.
I also tried Mystery Oil both in oil and gas. It seems to make the tractor smoke different (more but different smell and consistency).
As for results, I will say that when I inspected the plugs, cylinder 1 had plenty of crud around the tip so I am not sure if that was a result of the SeaFoam (which was in much longer) but I expect yes. Here is a picture of the spark plug...
So I plan on servicing the block and ordering an engine rebuild kit depending on what I find in there.
At the same time I plan on welding up a bumper and brush guard for the front. A very small oak tree leaned against the grill after I backed over it and nudged my grill and radiator, pushing the radiator into the fan blades. I have been so careful not to drive forward over anything but this proves that when clearing brush with a tractor, anything can happen.