Harbor Freight Idle Adustment

[thunder kart]

I'm new to the karting scene and have a 2009 harbor feight 6.5 hp engine. I would lioke to adjust the idle down a bit. I don't see any screws for this adjustment, I do see a black screw for what looks like the top end adjustment.
Thanks in advance for any light you can shine on this for me as karting season fast approches.

 

[Russ2251]

Associated directly w/carb butterfly. Screw is right there.

 

[nerfo]

There's a small, black, phillips head screw (at least on my 09' HF clone it's black) that will allow you to adjust the idle. It's directly on the top of the carb right next to the black plastic cam that attaches to the butterfly shaft. Turning it clockwise will INCREASE RMP, and turning COUNTERclockwise will DECREASE it. Good luck!

 

[devino246]

If the screw your talking about is under the air filter housing, then its the idle screw

 

[thunder kart]

ok, I've looked in all the replies suggested area, but allas I got my butt kicked. There is a black plastic screw under the air cleaner housing, but turning it while the engine is at idle doesn't do anything.
I also didn't see anything associated with carbs butterfly, I took the chokes arm off and looked around.
thanks alot for all the quick replies, pretty awsome. Great forum!
I'm not Mr. mechanic by any means, but I would like to think I know a little, enough to adjust an ide anyway.
This seems kinda silly that I can't find this screw, maybe it's controled some other way.

 

[thunder kart]

I'll try and post some pics by thursday night.

 

[Russ2251]

Be aware that an engine w/governor intact may or may not hold the butterfly closed when not running.
I suggest operating the throttle lever to witness operation of carb linkage.
When at a the slow setting the carb butterfly should come close to (if not actually touching) idle speed stop screw.

 

[thunder kart]

With the engine not running the butterfly stays open, when operating the linkage I can get the butterfly to close.
I wonder if the linkage itself is holding the engine at a pre determined idle.I see where there should be a screw, but there is a square black plastic cap that doesn't come off.
I think I'll take the factory linkage off and run it and see what it does and go from there.
If all else fails what would be some suggestions for a n upgraded carb? They don't seem like they're that much and would probably be worth the money so as to be rid of this hassle.
Thanks for the help.

 

[Russ2251]

With the engine not running the butterfly stays open

Normal.

I wonder if the linkage itself is holding the engine at a pre determined idle.

No. With engine running and throttle lever at slow position, butterfly meets idle speed screw. Unless you have something unknown to me.

 

[thunder kart]

I think a carb it is then this is becoming more work than it needs to be. Or worth, I'd like to have this thing on the road someday.

 

[solomon]

well it could have been done by now, if you had pics. All this should be is a single screw you turn in. If its not then 6.5hp CLONE engines are junk! HERE IS WHAT I WOULD DO, move the throttle cable and look on the motor what it moves, thier should be a screw pushing against what it moves. Turn that in some

 

[nerfo]

Due to manufacturing inconsistantcies of clone engines, chances are, your governor is doing a lousy job of returning the engine to a FULL idle. Umm... it's insanely difficult to explain exactly HOW a governor operates without some kind of awesome visual aid... a governors JOB is to maintain DESIRED RPM. It just happens to have a MAX of 3600. Anyway, if your governor spring is a wee bit too tight, it might be preventing the governor from returning the carb to idle speeds.

With the engine running, reach between the gas tank and the flywheel shourd and get your finger on the shiny metal arm with the black rod (that has a very light spring around it) and push the end of the shiny arm AWAY from the carb... if my thinking is correct, you should notice a drop in RPM. If that's the case, then your governor spring MIGHT be causing some issues. If you push the arm and the speed increases, the arm will fight your finger and try to slow the engine back down... this is completely normal governor action. Dink around with it and let us know what happens!

 

[Russ2251]

your governor is doing a lousy job of returning the engine to a FULL idle.

Most governed engines will not return throttle to full idle if not running.
Nature of the beast. There is a degree of variability between like engines.
Two examples follow. These are not running with throttle at slowest (idle) setting:
Briggs 5 hp pic #1
Briggs 7 hp pic #2
Once engines are started, butterflies will return to full idle.

 

[thunder kart]

Thanks Nefo that explains a lot. I messed around tonight and got it to idle like it needs to. But I took the governor off to do it. I'd like it on though I think it will make throtle cable hook up easier. I have to basically force the butterfly closed while the engine is running.
It seems like the spring on the governor that attaches to the little silver arm between the gas tank and shroud is making the throttle "bounce around and not stay at idle.
Thanks everyone for the help, I think it might be working, we're a little slow here in the midwest

 

[Russ2251]

"bounce around and not stay at idle

Called surging and is inherent in most all emissions carb equipped engines. A lean condition exits. To verify, slowly close choke to see if surging subsides. If it does, there are 2 options. One is to re-jet.

 

[nerfo]

I completely stole some companys idea (i forget who) and made my own, home brew throttle hook-up that re-uses some of the existing parts left over after a total governor removal... I posted some pictures on the start of my current project thread that are VERY close up and fairly detailed. Although I have yet to drive the go kart, the throttle set up works wonderfully from idle to wide open... I've been doing a LOT of testing, adjusting and re adjusting.

So, this is a link to the thread. I intentionally made these pictures as detailed as I did to help anyone with clone engine throttle questions... this is just what worked for me. The way I did it is by no means "THE WAY" to hook up a throttle! Hopefully it helps!

http://www.diygokarts.com/vb/showthread.php?t=6339

 

[thunder kart]

I totaly trshed the factory throttle set up and made my own with linkage thatoperates the butterfly using the governor body. I used a spring for the return to idle. It works great! I wish I would've done this from the begining. I'll try and post some pics this week.
thanks again for all the help.

 

[Blazkowiez]

If you're going strictly off of the butterfly keep in mind that your carb is aluminum and most butterflies have a rod made of brass. Each time you force it open and closed using that wire and a strong return spring it is very harsh on your butterfly, this is the same for Tecumseh, Briggs, or Honda. Keep this in mind that you're wearing out your carb when you hook things up this way.

There are linkage kits for operating the butterfly of the carb on clones/hondas that bypass everything but still have an external spring that does the returning without compromising the integrity of the butterfly. These things exist and you can really order them! As awesome as it is that we can make things from scratch and they work for a while sometimes the linkage assemblies I see people fabricate from scratch are very dangerous and do end up hurting people when they lock up. See if there is not a production kit you can purchase before you start rigging things up.

 

[thunder kart]

Thanks, Ill look around, I dont want to break it. I just got It working, ha ha.

 

[nerfo]

I think what Blaz means, is that, make sure when your foot is 100% on the gas pedal, the carb isn't under any unnescessary stress. Like, the gas pedal and butterfly shaft on the carb are perfectly in sync with each other. I had to make an adjustable stop for my gas pedal so I could tweak it and prevent exactly that. In fact, I left just a SLIGHT margin of error. 100% gas pedal position is about 98% butterfly open... that last two percent, I doubt I'll miss. I'm not running laps.