High idle when warm

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   Hey guys,
Need some help.  I have my 86' 2001 running great with exception to the idle.  It idles perfect as it should and were I set it when I first start my day then after a couple of runs it jumps way up?  I was thinking vacum leak or maybe the throttle plate sticking or something but at first glace does not apear to be either.  Any other ideas?  It has 1600 hours on it, would lower compresion cause this?

Any help would be great!
Thanks!

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wideopen44 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: April-11-2012 Location: Becker MN Status: Offline Points: 31	Post Options Post Reply Quote wideopen44 Report Post Thanks(0) Quote Reply Topic: High idle when warm Posted: July-12-2013 at 3:22pm
	Hey guys, Need some help. I have my 86' 2001 running great with exception to the idle. It idles perfect as it should and were I set it when I first start my day then after a couple of runs it jumps way up? I was thinking vacum leak or maybe the throttle plate sticking or something but at first glace does not apear to be either. Any other ideas? It has 1600 hours on it, would lower compresion cause this? Any help would be great! Thanks!

Bri892001 Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947	Post Options Post Reply Quote Bri892001 Report Post Thanks(0) Quote Reply Posted: July-12-2013 at 3:31pm
	How about the secondaries? Are the closing all the way? If you never go above 32 or so, will you get this condition?

wideopen44 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: April-11-2012 Location: Becker MN Status: Offline Points: 31	Post Options Post Reply Quote wideopen44 Report Post Thanks(0) Quote Reply Posted: July-12-2013 at 3:36pm
	Hmmm, good point, I checked the mains by taking the throttle linkage off and pushing back to closed and no slack so assumed it was not the plates but dumb me did not even think to check the secondaries. So you think they could be sticking after a hard run? That would make sense because I can idle around all day long until I have run it for skiing then it starts the high idle thing. I will check it out tonight. It they are sticking how would you go about keeping them from hanging up?

Bri892001 Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: September-27-2008 Location: Boston MA Status: Offline Points: 4947	Post Options Post Reply Quote Bri892001 Report Post Thanks(0) Quote Reply Posted: July-12-2013 at 4:43pm
	Secondaries sticking after a hard run is my theory. But, if you can cruise slowly all day without ever getting the high idle condition, it kid of confirms it. The vacuum secondaries are supposed to have a fail safe mechanical linkage that forges the secondaries closed when the primaries are closed, but not sure if this mechanism closes them all the way, or just most of the way. It could be the spring inside the secondary vacuum housing is busted. Or there could be some crud interfering with closure.

wideopen44 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: April-11-2012 Location: Becker MN Status: Offline Points: 31	Post Options Post Reply Quote wideopen44 Report Post Thanks(0) Quote Reply Posted: July-12-2013 at 6:30pm
	Thanks for the help I will check it out this weekend and see if I can solve the problem. Thanks much!

GottaSki Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: April-21-2005 Location: NE CT Status: Offline Points: 3363	Post Options Post Reply Quote GottaSki Report Post Thanks(0) Quote Reply Posted: July-12-2013 at 6:40pm
	Concur with Brian, How this happens... When the idle circuit clogs, the engine stumbles, so one ups the idle stop to make it idle again. However its now running on the transition slots that are fed by the mains instead of the idle fuel orifice in the metering block. This opened throttle plate position at idle now lets the secondary plates hang open a bit after a hard run, because the secondary closing-rod is now slack because the idle stop is far from normal. You can bend the rod to force the secondaries fully closed insead of letting them occasionally bleeding air, however it still won't idle that great and really behave off-idle until the idle fuel orifice is unboogared. Carb rebuild is in order.
	"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing." River Rat to Mole

wideopen44 Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: April-11-2012 Location: Becker MN Status: Offline Points: 31	Post Options Post Reply Quote wideopen44 Report Post Thanks(0) Quote Reply Posted: July-12-2013 at 6:45pm
	It was just rebuilt end of last season, but I do remeber one of the plates closing a little weird. It almost seemed like it was hanging up. Could a guy use a little emery cloth or something to make it close better or is that a no no.

High idle when warm

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