Help with 83 Mercury 115 idle adjust

[Jri93]

Can someone please identify what adjuster is the one that is referred to as the "idle stop screw" in the link and sync articles, used for adjusting idle speed.

My understanding is the idle speed is adjusted by adjusting the ignition timing at idle. I figure it is the left adjuster of the top two up above the top carb. However, i have read people talking about adjusting the screw on the bottom of the long vertical link arm. I know the top right is the max advance, and the top on the vertical link is the main throttle stop. Just not sure which of the other two adjust idle.

It currently idles about 1,100 / 1,200 on the muffs, trying to get it down to 900ish

 

[tommarvin]

Free factory service manuals at www boatinfo.no/lib/library.html

 

[GA_Boater]

See what the idle RPM is in the water. On muffs you have no exhaust back pressure and idle is higher than in the water.

 

[Chris1956]

If your idle speed is 1200 on a flusher, wait to adjust it until the motor is in the water. The idle stop screw is directly above the throttle cable attachment point on the throttle arm. The throttle cable adjustment must pull the throttle closed, with some preload, when the idle stop screw is adjusted correctly.

 

[Jri93]

Free factory service manuals at www boatinfo.no/lib/library.html

Thanks but i cant seem to find the correct one for my motor...

 

[Jri93]

If your idle speed is 1200 on a flusher, wait to adjust it until the motor is in the water. The idle stop screw is directly above the throttle cable attachment point on the throttle arm. The throttle cable adjustment must pull the throttle closed, with some preload, when the idle stop screw is adjusted correctly.

So if that is the idle stop screw, is that used to adjust idle speed or just adjusted to insure the carbs are closing all the way? what is the adjuster screw right next to the max timing advance adjuster? I am assuming that is the base /idle timing adjuster, which is what is used to adjust idle speed correct?

I will wait to test it in the water, but i just got the boat and the last owner did not exactly fix things correctly.. (allot of stuff jimmy rigged) so i want to make sure everything is properly adjusted. The Link and Sync article seems to reference more specifically to the older distributer ignition motors, not the ADI motor like mine.

 

[racerone]

What I would first check is the compression.----Then check for spark on all leads.----------Sometimes folks start adjusting idle speed to adjust / compensate for other engine issues.-------Idle speed adjustment normally does not change year after year.

 

[Jri93]

No Title

Thanks. The motor runs great though. just idles a little high causing it to be rough switching into gear.

Can someone confirm that the circled screw in the pic below is the one that adjusts the timing at idle...

 

[Chris1956]

The ADI motors were synched the same way as the distributor motors. The timing specs were different, though. The idle pickup timing spec is a specific timing when the carb is ready to start to open. The idle speed is usually set by retarding the timing from the idle pickup setting.

Since the motor is new to you, you probably should get a paper (pay) manual from mercury and do some reading. It will likely pay for itself in short order.