9.9f 2 stroke revs missing

[rubaiyat]

hi,

my engine starts fine and revs well in neutral. in gear, only firing on one cylinder when revved. have tries new plugs (twice) and replaced CDI unit (three times .. albeit with second hand parts). Before i buy an expensive new cdi unit, i want to be sure that this is the problem. what else should i be looking to eliminate?

Fuel is clean, carb is clean, engine very well maintained.

any thoughts appreciated

thanks

R

[rodbolt17]

my first thought?
PROPERLY test the CDI output at the failure RPM and load.

it is a very simple system.

if the CDI output is incorrect test the inputs.