Thanks guys. I will check wireing and make sure its correct and try setting again. Will report back later tonight.

I run 2 MSD boxes & distributors, I have 2 Craftsman timing lights with the dial, one is over 20 yrs.old, one is 5 yrs. old, both work perfect on my MSD ignitions.

With custom engines using after market ignition systems or the Mercury V6 ignition box, we just run the engines up to 4000+ RPM & lock at the targeted advance. In our case, we set at 40 degrees total. This can be done at the dock or on a hose. IMO, the initial advance curve prior to full advance is not relative.

Borrowed my cousins light and set it to 34 total, at the ramp. Ran flawless the entire time out. Think im good to go. Think my light is cheap pos. It was given to me and looks to be a harbor freight special. Lesson learned.

Friend of mine just ran into the same issue with same light on a HP HEI, seems these high $$$ lights are effected by RFI badly...my cheap no name light works fine !!!!