Idle setting Mercruiser 165HP

Y

YOBE

Seaman Apprentice
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Mar 12, 2019
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38
Hi,

Did the rebuild of my carb.
On the forum I saw the suggestion to start with 1.5 turns outward for the Idle screws (I have 2 on my carb 7040110).
Now my question is: I also have the screw for idle setting (the one linked to the trottle) that sets the "close" position of the 2 valves.
How should this be set?
I now I should aim for a RPM of around 600-700 in Idle.

Thanks
 
Scott Danforth

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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I am going to assume this is a mercruiser I/O and not an outboard. moving to the I/O forum
 
Y

YOBE

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Mar 12, 2019
Messages
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kenny nunez said:
You may have to re-adjust the idle stop screw with the boat in the water.
Click to expand...
So to be clear: the main rpm regulation is with the screw on the throttle lever and the 2 mixture screws are to make it run smoothly with that rpm setting.
 
Scott06

Scott06

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YOBE said:
So to be clear: the main rpm regulation is with the screw on the throttle lever and the 2 mixture screws are to make it run smoothly with that rpm setting.
Click to expand...
correct. when adjusting it get the rpms right then adjust the mixture. One screw at a time, go in to lean it (slowly give engine time to react) until it stumbles, then richen it up until it stumbles. Usually in between is considered best idle. then you may have to readjust the idle speed.

Final; idle speed is done in the water under load (in gear) 600-650 or so
 
nola mike

nola mike

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YOBE said:
So to be clear: the main rpm regulation is with the screw on the throttle lever and the 2 mixture screws are to make it run smoothly with that rpm setting.
Click to expand...
kinda sorta. The idle mix, timing, and dwell (we still don't know what we're working on) all have an effect on the idle. All need to be set correctly.
 
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