I just recently went through exactly the same thing with my 235 although it had only been about a year since it was started. Mine has a 12 volt ignition system in it. Remember, if you have a 12 volt system you need a ballast resistor to drop some of the voltage before it gets to the coil, or the coil will get hot. Other than that, starting it with a 12 volt battery doesn't hurt anything as long as you don't hook anything else up. You'll have to change bulbs, etc. to 12 volt or they will burn out. Most of the aftermarket parts houses have voltage reducers pretty cheap.
I didn't rotate the distributor or replace points, etc. before I tried to start, and was lucky enough so that the point gap and timing must be pretty close. It had a fuel pump on it, but I used an elevated lawnmower gas tank hooked to the carb because I didn't know how bad the gas in the tank was. I had problems getting it to fire and found out that there is a washer inside the tank cap with an orifice hole in it to keep the lawnmower from sucking too much fuel, I guess. Needless to say, it wouldn't flow enough gas to start until I took out the washer.
It still took numerous tries before I got it to run for a few seconds. Then it wouldn't start again. I put a hand pump bulb in my fuel line and pumped until I got resistance (like the needle valve had closed) and tried again. It started up but only ran for a few seconds again. I got it to run several times using that method, but the clear fuel filter I was using never got very full.
So I flushed the fuel tank and hooked the fuel pump back up to the carburetor. No fuel flow. The diaphragm must have deteriorated. I replaced the pump with one from Brother's, because my flaps kept giving me ones that didn't fit.
So then I had nice clean fuel to the carburetor, and the engine would run, but the idle was really high and it was running rich even after rebuilding the carb. I'm pretty sure that the fuel pump is putting out too much pressure and forcing the the needle valve off the seat, flooding the carburetor. Rochester B's like 3.5 psi. I got a pressure regulator, but haven't installed it yet.
Basically, if you got it to run for a few seconds, there's nothing major wrong with the engine. Compression may be low. but, if you squirt oil into the cylinders it may come up. Mine sure did. If your fuel pump is actually working, although it doesn't sound like it is, you may be flooding your engine. Check for a strong smell of fuel around the carb, or fuel coming out of the throttle shaft end holes in the carb body.
It sounds like your ignition is close enough. So pat yourself on the back. The remaining problem is probably in the fuel system, unless you didn't lubricate the distributor cam. That will wear out the rubbing block pretty quickly.
