Need help adjusting the idle on my 2005, 15hp Johnson

[waytooruff]

Hi all,
I have exhausted my search in trying to adjust the idle on my J15RSOC. I have played around with the the knob on the end of the throttle handle and tried to get access to the idle screw on the side of the carb without any luck at all.
Am I missing something obvious or does this motor have a problem.
Thanks for your anticipated assistance. Fingers crossed for an easy solution .

 

[racerone]

Post the results of a compression test.---------Did this poor idle show up suddenly or over a period of time ?

 

[waytooruff]

Hello racerone, The motor has only done around 15hrs since new so I am sure it is not a compression issue. The motor gave me problems on a recent outing, it would start and idle but bog down when trying to throttle up. I took the carb off and it was spotless but I did find a tiny bit off scale blocking one of the jets.Put it back together and all good now with it throttling up without an issue. It now just idles low and was wanting to just pick it up a little. Hence my problem now. Hope this makes sense.

 

[Vic.S]

The knob on the end of the tiller is the idle speed adjustment.

It is only a limiter on the twist grip mechanism so to increase the speed open the throttle a bit and turn the knob clockwise. Then you should find the throttle wont close as far as previously
Its quite a fine adjustment so quite a bit of turning is necessary to produce much effect.

if you run out of adjustment before you get it right you may have to look at where the cable outer is clamped on the engine and adjust that.

cant help if anyone has messed with the adjustment screw on the carb.

there does not appear to be an idle mixture screw

 

[racerone]

There are some adjusting screws for the throttle arm on the side of the motor block.

 

[waytooruff]

Thank you Vic.S and racerone for your respective responses. I am working all day tomorrow, but will follow up on your advice on Monday and will report back.
Your input is much appreciated.

 

[waytooruff]

Hi all, I ended up retightening the top cover and then adjusted the idle knob on the handle. Took it out to the local lake last night and it ran beautifully. Throttled up and down and idled smoothly.
Thank you racerone, and Vic.S for your input and assistance.
Take care on the water.