I have a MCI-5B with a 8V71 engine and automatic MT-647 transmission . At the present time the idle speed is set at 550 rpm's . A couple of people have told me that it should be about 625 rpm's for a automatic transmission. I want to know if I can adjust the slow idle speed screw without adjusting the buffer screw. I don't want to fool with that if I can help it. I have had some problems with the buffer screw in the past. Is adjusting the idle screw going to effect the buffer screw.
Marty Caverly
Yep you need to back the buffer out to set the idle speed then set the buffer, what you don't like the fast run away the buffer screw can cause lol
good luck
Once the idle is reset to 625-675rpm, make sure you reset your high rpm governor also. I had Don Fairchild reset my idle up a bit (keeps the cam gears from rattling) and the high rpm went from 2250 to 2400rpm. I like it though, so I kept it. On a 71 series, Detroit had marine engines that were rated at 2500rpm, so that meant that the no load was set near 2700rpm. Just don't try that with a 92 series-they don't like anything over 2300rpm. Good Luck, TomC