LO206 Not returning to normal idle

Double E Ranch

New member
I think I have an issue and am struggling to see what the problem is. Last night I had the kart on the stand doing some maintenance and cleaning, changed oil etc. Started the LO206 just fine and she idles correctly. I goosed the throttle at the linkage and the motor revved up but when I let off the linkage the rpm's came back down but not any where near normal idle speed. Linkage returned correctly and moves fine. I finally had to shut the motor off. Re-fired the motor, idle good but as soon as I goosed the throttle it revved up and kept the rpms way too high. It has never done this before.

Any thoughts here guys on what is going on?
 

steve baker

Moderator
We can usually correct this problem with the idle air adjustment screw on the right side of the carburetor. If this does not help lower the C- Clip on the needle 1 slot and then re-adjust the idle adjustment screw again. Most of the idle fuel is delivered from the .032 inch diameter hole in the floor of the body in front of the slide, but some portion of the fuel / air is from the main nozzle, so that is why I am telling you to adjust the needle C-Clip one slot and try that. It's kind of a tricky problem we also run into with the LO206 engine cause of the camshaft overlap in the idle condition.

Steve
 

Jimbo

You can fool some of the people some of the time
Especially if you are at high altitude (Colorado) and have leaned it out.
Like Steve said. It's too lean.
 

Double E Ranch

New member
I have checked the slide in the carb and it goes up and down and returns just as it should. We are in the plains so altitude is not and issue. Looking at the carb on the right side I see the idle and mixture screws. To increase the idle what way do you turn the screw. I have turned it and it seems to have little to no effect? Runs just the same.
 

Kart43

Member
Direct some air through the cable and then lubricate the cable. If the carb slide is free and the pedal is free, the idle adjust screw does not change the idle, either the slide is held above the screw, or you are drawing air after the carb.
 

Jimbo

You can fool some of the people some of the time
If you don't have any slack in the cable it could be holding the slide open so the idle speed screw doesn't have any affect,
Personally, i don't like to have slack in the cable and i make a throttle linkage kit that allow you to adjust all the slack out of the cable.
Then you can back the mixture screw out and adjust the idle with the brass nut under the rubber boot on top of the carb.
The idle speed screw is the one in the center of the carb on the right side and the idle mixture is recessed slightly and located next to the air filter.
Turning the idle speed screw clockwise should increase the idle and turning the idle mixture screw in will lean out the mixture.
http://www.fastermotors.net/TheMissingLink.html
 

dylhainen

New member
I'm having this same issue but worse. I'm on the track and I let off the throttle and it only drops down to 3800rpm instead of its true idle speed when its started which is 2200. Not only that if I go full throttle an let off, it will actually continue to accelerate on its own!! the cable is loose when I let off the throttle.....I can't figure out why its doing that.....guess I have to take the whole carb apart and ensure all is well
 

Gab507

Member
First make sure the spring is inside the slide and the slide is installed correctly with the long slot on the left when looking at the carb, 2) Disconnect cable from carb and make sure the throttle cable moves freely. No kinks or dirt in the casing. Good idea to replace. At about $3 for a cable and 0.50/ft for nylon housing it's not worth the trouble. 3) with the cable still disconnected make sure the pedal moves freely. I had a customer that tightened the pedal to take some slop out and snugged it just a little too much. 4) make sure you have a strong return spring on the pedal. Some of these seem like common sense but I have seen each of these on more than one occasion.
 

alvin l nunley

Site Supporter
Is there any chance you have an air leak. High reving engines need air and fuel to rev like that. If you're rich, and you get some extra air, it's going to do what your seeing.
 

Chipg56

Member
With any carb problem especially when running gas, the first thing to do is to completely disassemble and thoroughly clean. If that does not cure the problem then proceed with the above. If the motor runs well at the track be hesitant to move needles, ect. If the idle is high but not engaging the clutch ask yourself if it is really a problem at all. The key to remember is that no one ever won a race sitting on a kart stand.
 

alvin l nunley

Site Supporter
With any carb problem especially when running gas, the first thing to do is to completely disassemble and thoroughly clean. If that does not cure the problem then proceed with the above. If the motor runs well at the track be hesitant to move needles, ect. If the idle is high but not engaging the clutch ask yourself if it is really a problem at all. The key to remember is that no one ever won a race sitting on a kart stand.
That may be true but Dave Knapp once won a race while sitting on the side of the track when the checkered flag came out.
The rule at that time was, for induros, most laps in an hour. Dave had 2 1/2 laugh lead on second-place when he broke on the last lap. He had the most laps in an hour. They changed the rule after that.
 
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