idle question

[bbf]

is there a way to lower the idle on a 250 cumm

 

[Gamagoat1]

What is it idling at now?

 

[bbf]

around 1100 rpm

 

[Gamagoat1]

I don't have a drawing that SS will accept (BMP) so, if you look at your IP on the right side there is a little bell shaped housing with a pipe plug in it's end. Probably with a wire thru the plug to seal it. This houses the shim pack that controls idle etc. Start your engine and let it run for a couple of minutes. Shut it down remove the wire seal and remove the plug. Let it drain, insert a small straight slot screwdriver and turn left just a little. (maybe a quarter turn). Re install the plug with teflon tape and start your engine. If you are lucky it will keep running if not just prime the fuel system as normal.This may have to be repeated untill the right rpm is realized.
If turning this screw has no effect then the shim pack will have to be adjusted.

 

[CCATLETT1984]

if you lower the idle too much, you will rattle the filaments loose inside the headlights.

 

[bbf]

what should the rpm at

 

[BEASTMASTER]

a cummins should idle around 550 600 .

 

[WillWagner]

Gammagoat1 is correct, but, i'd check other thngs first. Make sure the throttle arm is going all the way back to the idle position, take the linkage off...not the arm bolted to the f/p throttle shaft...and see if it changes the idle. When it starts, cold, is the idle normal...around 600-650 rpm..550 is too low, it will vibrate so bad you wouldn't see out of the mirrors. If it is, and increases as it runs or warms, there is a restriction in the return, or, it has too much throttle leakage.