Mike:

I'm not sure if you mean that there is no spark on 2 spark plugs (in which case I would recommend replacing the rotor and cap), or that 2 of the cylinders are not providing power -- In which case I would remove the spark plugs in the corresponding cylinders and do a simple compression test by placing my thumb over the hole and cranking the engine over.

If the pressure forces your thumb off the spark plug hole -- the compression is okay. If it's okay, I would then check and make sure that I have the spark plug wires in the proper firing sequence 1-2-4-3.

If there is no pressure on your thumb -- you have a problem with stuck valves. In which case you can try to free them up by using a long, thin screw driver in which you have put a bend in the end so that you can use it to pry the stuck valves closed. However, before a would do that, I would shoot 3 or 4 sqirts of Marvel Mystery Oil into each of the cylinders and let it soak in for a while. Or if you feel more ambitious, you could remove the valve cover plate, located on the carburetor side of the engine and try freeing up the valves from that location.

Good Luck and let us know how you make out.

Steve Kaminsky