Proper idle speed and adjusting idle on 1998 Mercury Force 120 HP

[joshbosh]

I've been experiencing some issues with my 1998 Mercury Force 120 HP ELPT, serial number OE323046. It tends to die quite frequently when in idle and occasionally dies when shifting into gear. I'm wondering if my idle speed is set correctly. Anyone know an easy way to verify the proper idle speed? When cold, it idles at a little over 2000RPM and settles in at around 1800RPM once warmed up. Does this seem right or is it too low?

If it needs adjusting, I'm wondering if the screw circled in the attached picture is the proper idle adjustment screw? Can someone please help me verify?

Much appreciated!

 

[SkiDad]

Your picture is small, but no those are not the idle screws - those are for fuel mixture - if you changed them set them to 1 1/4 turns out from lightly seated. If you didn't' touch them then don't adjust them.

the idle adjustment is at the bottom of the timing tower - there is a lock nut and large flat head screw that you adjust - turning right raises idle. When do make sure to tighten the lock nut.

i'm guessing you meant 800 rpm after warm - if so, that is too low - you need to be about 1000-1100 in neutral so that it's about 700-800 in forward gear (it depends on what pitch prop you have)

 

[SkiDad]

see this link: http://forums.iboats.com/filedata/fetch?id=6989558

 

[joshbosh]

Thanks SkiDad for the info and the picture. My tach reads 1800 on idle. Maybe the tach is messed up? Does 1800 seem high? It sounds to me like it's idling a bit low, especialy since it's dying intermittently, but I'm no expert.

 

[SkiDad]

not sure what kind of boat you have it on, but the earlier force engines required a special tach that is 20 pole - they don't make them anymore i believe. But I'm not sure about your late model force it might be just a standard tach b/c some stuff is mercury on that one - if so make sure it's set for 4 cylinders on the back.

It does sound like your tach is reading high then - i would try raising the idle a 1/4 turn and then see what happens. You want it to clunk into gear but not slam into gear when you shift from neutral to forward.

 

[joshbosh]

I'll give that a shot, thanks for your help.