I'm keeping this brief but can provide more background if needed.
My '48 8N runs but roughly at higher engine speed. Battery, spark gap, wires, points all have been checked, seem to be in spec. I suspect a stuck valve may be part of the problem. I ran a compression test and got 90#, 100#, 30# and 60# front to back.
Because I have never worked on this part of the engine I thought I would ask here for advice. Should the manifold come off? Should the carburetor come off? Anything else?
When I have removed the covers what am I looking for? If I find a stuck valve (open, I hope) what is the recommended procedure to try to loosen it?
When I replace the covers, what should I be careful to do or not do?
I have the manuals but I don't see much on the subject there. Thanks for your suggestions.