The FSM says to hook an external tach up to set the idle speed but is this really necessary? I was thinking of having a buddy get in the cab and race the engine at 2,500rpm then I'll adjust the screw until they tell me I'm at 750rpm. Would this work?

Also, when setting the idle speed does the diagnostic box need to be jumped like it does when you are checking the timing?

 

I just run back and forth. It gets really old lol. Same question on the idle. I had mine jumped and it seemed to work just fine.

 

Haha, I would rather run back and forth than spend the $$ on an external tach that will never see any use.

The reason I ask about the jumping is, it doesn't say to jump the connection if you're reading the maintenance portion of the FSM. However, if you read the timing portion of the FSM it will have you jump the connection first and the next step is check the idle speed.

 

i adjusted mine on the fly with a dime...

i used the calibrated ear.

 

I believe that you are supposed to adjust the idle while it's jumped to ensure the idle is correct to set the base timing. The idle adjustment screw (warm) seems to be purely mechanical. I don't think it will hurt anything to adjust it further after you set the timing. Just make sure the idle is correct while setting timing. It is critical.

 

Yep I do the run back and forth thing too hehe

 

just listen to how it sounds, not low enough to the point of stalling not too high that it takes off too fast in gear. simple.

 

I'm a stickler for OEM settings , I set it on the 850-875 on the tach , takes a few trips but your only walking .