LO206 idling way too high

  • Thread starter Deleted member 21174
  • Start date
D

Deleted member 21174

Guest
Cleaned and reassembled the carb for an LO206.

Briggs recommends only turning the idle speed screw out a max of 2 1/4 turns but the engine is idling way higher (3000 RPM!) if I do this.

It's cold and high pressure (air density is 100% or 101%) should I turn the idle speed screw way in? Is a high idle like that a sign that there too much or too little fuel in the bowl? (I'm running around .900 for a blue slide).

To get the idle speed down can the screw be backed out 3 or 4 turns or is this too much?
 
I can check that. I think it's ok but worth checking. I have a new air filter. The old one was over oiled and had been mushed in some wrecks. Maybe the new filter is flowing air better? Or could there be an air leak between the carb and the intake manifold?
 
pull filter off look in to see if slide is all the way down.
Next while looking inside turn the idle screw to see if the slide is moving up and down as you adjust the screw.
Of course that's if the cable is not too tight.
 
I've noticed that you seem to be really getting into this karting thing. Watch out it can be habit forming / addicting.
If the throttle cable isn't holding the slide open farther than it should i would look at things that would cause a lean mixture. Some of these things have been mentioned already, such as the intake manifold gasket. I would also make sure you didn't lose the "O" ring on the flange where the carb is bolted to the intake manifold. While your at it lay a straight edge across the flange and make sure the "O" ring sticks up high enough to provide a seal when the carb is bolted to the manifold. Then take the "O" ring out and lay the straight edge across the flange again to make sure it isn't warped. An air leak here will lean things out and cause a high idle.
Sometimes other people drive over your carb and bend the black intake manifold slightly.
If it's bent a lot it's an obvious problem. If it's bent a small amount it's more difficult to find. Lay your straight edge across the ears on the black intake manifold to make sure it isn't bent.
Sometimes it doesn't show up right away. Taking the carb off or wrestling with it may have been just enough to make it start leaking.
The farther you turn the idle mixture screw out the leaner it gets and up goes the idle. Don't be afraid to turn the idle mixture screw in farther than Briggs recommends. (2 1/4 turns)
The leaner you make the slide needle the higher the idle will be also.
The richer you make the slide needle the lower the idle will be to the point it will not idle.
 
If you just cleaned and reassembled the carb, and are not too familiar with it, the metal slide (cylinder) in the carb may not be oriented correctly. Keep rotating it until it seats correctly then start engine and check idle.
 
I'm having a similar issue with my sons LO206. As suggested above, I took the air filter off and can see a small amount of lift/drop in the slide within the first two or so turns of the screw. Nothing happens after I back the screw off beyond two or 2.5 turns. There is slack in the throttle cable so I think its dropping as low as the needle will let it go. The needle is in the center (3rd) notch. The mix screw is backed off about 1.5 turns. It is pretty cold here today. 40 degrees, 30.14 air pressure, and 59% humidity. RPMs at idle are still over 3000. It'll occasionally drop down a bit after I raise the RPMs and quickly drop them like in a braking scenario. I get a quick backfire when I release the throttle and the RPMs drop down into the mid 2000s, but then it moves back up to well over 3000 RPMs at idle. Will octane affect idle? I think it was tuned at 87 octane but we may have put higher octane in it from a gas can I had at home. We recently installed a brand new air filter. Taking it out for some track time in two days so I guess we'll see what happens once the engine really warms up (temp that day should be about the same but with a bit more humidity as a significant rain is coming through tomorrow). Any advice will be greatly appreciated. We're very new to this and bought the kart used from a guy who used the kart as a teaching/rental kart so the engine is broken in. Running the gold slide at GoPro in Charlotte. Thanks!
 
Start by checking for air leaks on intake.
Spray some carb cleaner at the gasket on both ends of the intake manifold.

If rpm changes, this will be your problem area.
 
You must log in or register to reply here.
Back
Top