Recently been getting intermittent low and sometimes rough idle of my 81 40...barely stays running at times...runs fine with just a little choke. Otherwise runs great...egr disconnected and FCS direct wired. I've had some previous issues with carb I've been able to correct with carb cleaner and fuel additive. So I suspect some partial blockage of slow circuit. Carb has never been rebuilt at least to my knowledge and I've owned it since 1988. So I figure that needs to be done sometime. Anyway, my question is what is the best way to clean carb without total rebuild? Or if anybody has other ideas let me know. Thanks in advance.