150 idle problems

[njo1]

i have twin 2003 150 carburated 2 stroke mercurys
on start up both are fine and after a few minutes they boyh idle between 700-800 rpm. after running for a half our or more port engine idle drops to 500 or less and stalls out. if i adjust throttle higer on next cold start up it is idleing about 1200. could this be a trigger problem? stator has been replaced and carbs rebuilt still same results.
not sure what to do next

 

[Faztbullet]

Re: 150 idle problems

From what you have posted it kind of sounds like a CDM module/s is dropping causing low idle but I cant see them causing high idle at restart. I myself would look at the shift switch as if sticking it will advance timing 3 degrees or swap the Idle/contol module between engine as it may have a problem.