Spacers?? Take those off, clean the plugs, and put them in normally. Do you have a nice healthy spark? Are the carbs overflowing or empty? If overflowing either too much fuel pump pressure or grit holding the float valves open. If empty, a clogged or holed fuel line, bad fuel pump, or clogged fuel filter. As difficult as it is to get SU's perfectly tuned and balanced it isn't hard at all to get them close enough to at least run.