Edelbrock variable idle


10 replies to this topic
  • Ian_FE501

Posted January 21, 2008 - 11:25 PM

#1

Hi,
I've had the E on for a few rides and it works well except for some strange idle antics, particularly 'hanging' a bit which is often noticed on downhills when the engine braking isn't quite what's expected, then on other occasions it will idle very low and stall. I'm pretty confident I've got it tuned OK as the fuel economy is similar and there is slight backfiring on the overun like the original, anybody seen this? Thanks Ian.

  • creeky

Posted January 22, 2008 - 04:32 AM

#2

I would try 1 or 2 clicks richer on the needle adjuster.

  • xr650l bum

Posted January 22, 2008 - 06:50 AM

#3

I would try 1 or 2 clicks richer on the needle adjuster.


+1. Make sure your cables are not binding.

  • husky123

Posted January 22, 2008 - 09:38 AM

#4

yep on the above advice. A hanging idle is usually lean condition. Just click it right until it settles in. Remember quick blips with the E will sometimes
mimic a lean hang but it is just burning the fuel from the accel pump.

  • Ian_FE501

Posted January 22, 2008 - 04:31 PM

#5

Thanks fellas, I'll start fiddling, unfortunately I have the Acerbis tank and I have to take it off to get at the trick adjuster.

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  • Krannie McKranface

Posted January 22, 2008 - 06:44 PM

#6

It will also hand if it is too rich!! I adjusted mine two clicks back, and it went away.
Also, Edelbrocks return spring is weak, so you may just need to adjust the spring for a more robust return (remove and tighten one turn).

  • Ian_FE501

Posted January 30, 2008 - 10:00 PM

#7

Good note Krannie, I suspected the spring wasn't up to fully closing the slide but discounted it as nothing changed when I force closed the throttle. I then realised that the return cable didn't actually fully close the slide. So yes the hanging idle was caused by the return spring not overcoming the huge suck of the engine on the over-run, the idle is still variable but seems to be better with a choked air filter - I'll richen it a click and see.
Ian

  • fjfilips

Posted February 14, 2008 - 09:58 AM

#8

I will jump in on this thread with some additional possible causes of a hanging idle on the Edelbrock. I have had it apart myself about 3 times, and I have sent mine back to Edelbrock twice in an attempt to solve the hanging idle problem & I think I finally got mine solved.

Throttle wheel not returning fully:
Need to ensure visually that the throttle cable wheel returns fully to the idle adjustment screw (when idle hangs, grab wheel & ensure it is fully seated). If the wheel is not going all the way back, then your problem will be poorly routed cables, misadjusted cables (pull cable does not have enough slack), weak carb spring (put another twist into the spring by removing the shaft), or the accelerator pump/ pump linkage is sticking (I had this problem at first).

If the throttle wheel is firmly returning to idle position:
A lean idle get can mimic a hanging idle, try enriching the idle jet setting.
Too much accelerator pump injection can mimic a hanging idle while the excess gas is burnt off, try reducing the accelator pump (or better yet, just disconnect the linkage for testing)
Verify throttle cable wheel is firmly affixed to the shaft.
Remove top of carb & verify that the slide and metal shim that wraps around the shaft to pull on the slide are attached and free moving.

I had verified all of the above several times in my troubleshooting before I stumbled on my personal cause of a hanging idle (with throttle wheel returned fully). I removed the float bowl and verified that the float level is correct. However, there is some "brillo pad" type material at the bottom of the float bowl, which I assume is to help keep gas from sloshing. However, upon close inspection I noticed that the needle attached to the carb slide sticks out of the bottom of a brass tube into the bottom of the float bowl. There is a recess in the bottom of the float bowl to allow room for the needle to drop fully. However in my particular carb, the "brillo pad" material was covering this recess. This meant that occassionally when rolling off the throttle the needle would get caught in the brillo pad and physically hold the slide up enough to cause a fast idle. A quick blip of the throttle was enough to force the needle through the material and it would return to a normal idle.

Solution to my problem was simple enough. I removed the brillo pad and made a cutout over the recess in the bottom of the float bowl (it is held in place with a metal plate, so the material will not move around). Now the needle is free to fully drop, along with the carb slide, and my hanging idle is gone. I am not sure if this is a problem from the factory in other carbs, or was caused by an Edelbrock tech forgetting to cut the notch when my carb was rebuilt (to fix my original hanging idle problem - a stiff accelerator pump linkage).

Hope this helps someone else.

Frank

  • Agent2

Posted February 14, 2008 - 10:38 AM

#9

fjfilips - my Edelbrock has the sticking accelerator pump problem. My weekend project is going to put one more twist on the spring. Is there anything to look out for when doing this?After taking off the top of the carb it looks like I remove the circlip and pull the shaft out and rotate once, any small parts to keep an eye on?

  • creeky

Posted February 14, 2008 - 02:59 PM

#10

fjfilips - my Edelbrock has the sticking accelerator pump problem. My weekend project is going to put one more twist on the spring. Is there anything to look out for when doing this?After taking off the top of the carb it looks like I remove the circlip and pull the shaft out and rotate once, any small parts to keep an eye on?



In case you don't have this link, here it is.

http://www.edelbrock...b_internals.pdf

  • Agent2

Posted February 14, 2008 - 03:39 PM

#11

Creeky - you da man. :applause: Gracias





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