cdi

[blackiron]

i have a 90 h.p. yamaha half power at full throttle carbs rebuilt the coils are good how do i test the cdi thanks.

full model number please

First you need toconfirm it is an ignition problem.
Some Yamaha manuals do provide CDI resistance checks but it is difficult and inaccurate. It is better to confirm the cdi is defective through a process of elimination, confirming all other ignition components are good, than changing the CDI.