datzenmike

I know people talk about worn bushings in the distributor but I've been looking at exploded diagrams of L16/18 20B Hitachi distributors and see no replaceable bushings for the shaft.

It's likely that the aluminum casting of the distributor body is simply drilled to fit the shaft and serves as the bushing too. The casting should be more than enough to support the spinning shaft. The EI distributors don't have to push against the spring on the points, all they do is just spin. And shaft wobble might cause problems with the points opening and closing but the EI just uses magnetism to trigger the coil firing. Once triggered the EI module has a circuit that prevents multiple firings.

Not much you can do about any shaft/case wear so unless you can detect  some kind of miss firing, I would leave it.

The EI does have a superior spark so it's easier for it to find a shorter path to ground. Insure that cap/rotor/coil/wires and plugs are in good shape and that the only available path to ground is through the spark plugs.

Thank you Sir, I wondered if some play was acceptable but it seems to me to be more than I would like. I can wiggle the shaft by the rotor and can also wiggle the whole distributor as well. I think this is affecting the accuracy of when the spark is delivered to each plug. I dont have a  distributor curve machine so cant really tell. The engine symptoms are poor idle, slow accel, popping back through the carbs etc. My air fuel gauge shows it to go very lean under light throttle around 2500rpm. It runs best at wide open throttle. Plugs are good but on the dark side, probably from the hard start cold continual restarts.