Gx 200 speed question, via video

[peteclark3]

Hey guys, thanks for all your help so far. I made a video with a problem I'm having here..

http://www.youtube.com/watch?v=TOcuai19c2Q&sns=em

I just put a new gx200 clone on my go kart, I'm a newbie as you know from my other posts.. And when I take it off choke it takes off.. Could be the throttle linkage I set up, I dunno.. Thanks for looking!

Pete

 

[Doc Sprocket]

Take the chain off, before proceeding.

Now- that black mystery screw IS the idle speed adjust. I've never seen one that has no way of sticking a screwdriver in. See if maybe a cap will pop off.

Completely disconnect your throttle cable, and start the engine. Take the chonke off, and see if the carb butterfly rests against the tip of that plastic idle screw. If it does not, your governor is possibly out of adjustment.

If it does rest against that screw and it does idle nicely, the problem lies in your throttle cable/attachment. If it rests against the screw and still runs way too fast at idle, turn that screw out until it idles nicely.

 

[peteclark3]

Stepping back a bit..

When i got the engine, the throttle metal lever thing was screwed on tight and didn't move at all.. In the slow position. Should I just look for a proper throttle linkage for a go kart for this engine.. Or is the way I have it okay?

 

[peteclark3]

Also, I'm pretty sure the butterfly doesn't rest against that screw but I'll check. It's a new engine out of the box.. How likely is it that the governor is out of adjustment? To be clear, which part is the governor?

 

[Doc Sprocket]

The governor starts inside the engine, and extends all the way to the throttle butterfly on the carb. It's not a "part", it's a system comprised of many parts. I advise you to read this: http://www.diygokarts.com/vb/showthread.php?t=16518

It's probably NOT defective out of the box, but it's possible. As a matter of course, you need to back off the nut on the hand throttle so it moves freely, and attach a return spring to it, so it always returns to idle.

 

[qtband]

The butterfly won't rest against the idle stop when the engine isn't running so make sure you check when it's running.

 

[Doc Sprocket]

Can we get some good still images of your throttle connection/linkages?

 

[peteclark3]

I ran the engine without the chain on as instructed, and noticed that after I push the throttle and release, while the throttle handle goes back to where it should, the idle butterfly doesn't get all the way back to resting on that black screw. There's about 1/8 inch between them (maybe less), and when I push it back manually, it matters a -lot- and idles perfectly.

So I guess the question is, what spring is supposed to be getting that idle butterfly wing to touch the adjustment screw? I don't see any, and I tried oiling the butterfly a bit but it didn't help (maybe I didn't use the right oil, etc).. maybe another spring is too tight preventing the butterfly from getting all the way back to resting on the screw.

Thanks for your help, feels like we almost got this licked!

 

[OzFab]

As far as I'm aware, there is no return spring, you have to install one...

Figure out where you can mount one to work efficiently, measure the length then go to your local auto parts store & ask for a throttle return spring 1/4" - 1/2" shorter than what you measured; the shorter the spring the better/quicker the return will be.

 

[Doc Sprocket]

There should be a long, light spring coiled around the rod that connects to the throttle butterfly. Do not just randomly connect any old spring to the throttle butterfly- It will throw the governor operation right out of whack.

 

[GregMartin]

Lots of good info here. I wish I had seen Toystory's post on governor removal and the chance of flywheel failure. I ended up doing as he suggests and not upgrading the valve springs when I removed the governor on my clone so that the revs were somewhat limited.

Also the governor arrangement is sort of delicate and won't work if that fine spring that's on the throttle rod is not connected correctly. Even though it kind of looks like it is doing the opposite of what you want.

You will probably have an easier time if you remove the governor and build a decent throttle linkage.

There is lots of info on this web site and elsewhere online about how to do this on a Honda clone. I would definitely do this modification. With the governor removed you can replace the throttle actuating spring with a solid rod and pretty much leave you throttle linkage as is. On my Honda clone I found that the throttle mechanism had very loose tolerances and I didn’t like the way moving plate moved on the fixed plate when I loosened the nylock nut. A solution was found when I removed the governor components from the crankcase. One of the governor components is a small plastic pin/plug that pushes on the throttle leaver. I discovered that the inside diameter of the plastic plug was the same as the stud protruding from the base plate of the throttle mechanism and the outside diameter of the plastic plate was the same as the hole on the moving section of the throttle assembly. I cut the end of this plastic plug with a hacksaw and fitted it into the throttle assembly which basically eliminated all the play and allowed for smooth reliable operation.

In addition you should disable the low oil sensor as this can cause the engine to cut out when the gokart is in motion. This is easy to do simply unplug the yellow wire that come out of the crankcase and goes into the gold coloured relay. Also unplug the black wire from the relay and remove the relay. Connect the black wire that comes from the ignition to the on/off switch and your finished. There is a second connector on the black wire that you can use for a remote kill switch or to drive a Tachometer if you want.

Ok hope you can make use of some of this info.


My Oh Five
www.diygokarts.com/vb/showthread.php?t=18728