Real time compression test help. (1 Viewer)

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And then there are hoses that blow. :hillbilly:

Getting the idle mix and speed right is a "sweet" spot exercise.
With timing set, and all connex correct, I set my tachometer over the air cleaner and use the small screwbit between fingers to increase / decrease IM, waiting 15-20 seconds to see any change on the tach. 2 turns out is fsm starting point.
I like to get rpm up to 700-710 initially, and then go to the ISpeed screw with different screwdriver to take the rpm back down to 650, (the fsm for my '77 fj40 gives a tolerance of +/-50 rpm) so you could reduce speed to 600 before the next step.
Switch back to the IM, turn it to increase speed to fsm setting of 690, if it goes faster than that, decrease with IS.
It can be frustrating, the ideal sound is similar to well oiled whisperclatter of a sewing machine. Right JimC?
 
Last edited:
I stand corrected only recently by Jim... IM can be set to as much as 3/4 turns out as a starting point.
 

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