Idle RPM to High

[kenfyoozed]

Just finished getting ski back together. 97 GTX 787. Redid all oil and fuel lines. She fired right up but now the idle RPM is at 4000, up from 3000 where is was before. Im running it without the flame arrestor and air box at the moment. I this the reason for the higher RPM? I have backed the idle screw all the way off with no change. Should I just adjust the cable to give more slack? What should I check or where should I go from here?

 

[kenfyoozed]

double checked the manual and sure enough I should have the arrestor and air box in place. So i re installed all of that and then check the idle. It was the same, maybe 1-200 rpm lower. Removed the air box again so i could adjust the cable. It didn't take much adjustment, maybe 1.5 turns on the jam nuts of the cable to get it down to 3000rpm. Left the airbox off for now in case someone says I should have done it differently or check something else.

 

[AKnarrowback]

How much slop do you have at the throttle lever at an idle? If the cable is adjusted to tight the carb will be held open and the idle will never go down.

Double check the cable adjustment. Keep an eye on your oil injection adjustment and readjust it after you do any throttle cable adjustment.

I never liked the adjustment outline in the shop manual, it doesn't address having the cable too tight that could change the idle.

 

[kenfyoozed]

How much slop do you have at the throttle lever at an idle? If the cable is adjusted to tight the carb will be held open and the idle will never go down.
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I think this was the problem as there was no slack and it would not allow the carbs to idle down. I loosened it up and it seems better. Rams dropped down to just under 3000. Thanks for the reminder to check the oil injection as well. I will do that to confirm it still is within specs.

I think what may have happened is that the jam nuts of the cable were not super tight and in the process of taking the brakes off the carb the entire unit spun around the cable taking out the slack that was there.

 

[mikidymac]

You should never ride the ski with the aribox off or it will run really lean and hurt the engine.

 

[Sportster-2001-951C-Stock]

Yep, sounds like the cable was adjusted too taught. There should be a good procedure in the manual but if you want I can whip up my version.

 

[kenfyoozed]

You should never ride the ski with the aribox off or it will run really lean and hurt the engine.

I was not riding the ski, it was on the trailer connected to the hose just testing the rebuilt carbs.

Yep, sounds like the cable was adjusted too taught. There should be a good procedure in the manual but if you want I can whip up my version.

There is and I followed that. After adjusting the idle the oil injection marks were a bit off so I adjusted those and got the marks to properly align. Thank goodness I had an inspection mirror to be able to see them.

Got it all back together and she seems to run better but will test it out on the water tomorrow.

 

[AKnarrowback]

Good to hear.