How to adjust idle 2007 4.3 Mercruiser TKS

[TimTJR]

I just bought this 2009 Crownline with 2007 4.3 TKS Mercruiser. Can someone explain how to adjust the idle? It runs excellent however after the engine is warmed up, it idles at 800 rpm. I want to idle it down to 700-750 because of 2 problems. 1) it grinds into gear. 2) it diesels when turning off the engine (especially after getting the engine temp up to 180 degrees from driving it fast) I have found ways from forums to get it to stop dieseling such as letting it idle for a couple minutes before shutting the engine off and putting higher octane fuel in. But I think idling down would also help. Also, I really hate hearing the gears grind and jerk into gear. I just don't know how to adjust the idle on this. Can some help please?

Thanks,
Tim

 

[Scott Danforth]

the manual covers this. check the stickies for a link to the on-line manual

I believe the idle should be 650 in gear

should only be a single screw to adjust, however your cable could be hanging.

 

[porscheguy]

The normal operating temp for your engine is 160degrees. Even running at WOT, you may experience a few degrees temp increase but 20 degrees means you’re either running it at WOT way too long, or you’ve got a weak impeller or a thermostat that’s not working at its best. And this is in addition to the possibility of running lean, low octane, etc.

Lowering the idle isn’t going to prevent dieseling. Grinding and jerking into gear is a fact of life with the alpha drive, but you’d be better off adjusting the shift cables rather that turning carb screws to make it shift better.

 

[TimTJR]

Thanks for the reply Scott. The cable is secured as it should be. I tried posting a picture but I can't figure out how to make it small enough. I am new to iboats so what is the stickies? I've adjusted the idle on many Outboards by the adjustments on the cable but this is my first I/O engine and it looks a bit different. I do see a screw with a spring on it.

 

[alldodge]

engine is warmed up, it idles at 800 rpm

With the motor fully warmed up.
the carb idle adjustment screw is full backed off the stop
the throttle cable removed from the linkage

Now if it still is idling above 700 rpm, see if the TKS module has fully extended to shut off enrichment. If it hasn't, remove the module and measure the length of the plunger. From the face to the tip it should be 1.25 inches with voltage applied for at least 10 minutes

 

[TimTJR]

Porsche guy I have only ran it wide open a few times. And have not ran It Wide Open very long. I would say 2 minutes at most.

it doesn't hit 180 but it does get pretty close. After running it and letting it idle for a couple min with the blower on, it goes down to about 160.

I read a few Forums on iboats that says too high of idle can cause dieseling.

Why is it better adjusting shifter cables?

Thanks
Tim