6HP tecumseh idle issue

[Unit 91]

I just got a kart off craigslist. 6 hp Tecumseh power sport. starts up by the second try every time. now I'm not 100% familiar with small engines, so please excuse my ignorance.

it has an issue with the way it idles/ accels. if you start it up and keep the choke CLOSED the engine idles super slow and almost dies, which I assume is pretty normal do to the low amount of air allowed into the engine with the choke closed. it always stays running but just barely. then you move the throttle and it starts to rev super high, like its running away.

if you OPEN the choke the engine just revs up and starts screaming. even with the throttle fully closed.

it seems like you either have full throttle or no throttle with this engine. I am assuming this is going to be a carb or throttle linkage issue.

ill add some pictures from my phone just as a reference.

 

[Unit 91]

 

[rocketkart]

may wan't to try backing out this screw a lil till it idles good as it is the idle speed adjustment. it look's like it's way in there.

 

[Unit 91]

ok what does that directly adjust? the throttle, the choke, or the fuel flow amount?

 

[rocketkart]

it directly adjust the throttle wich is the idle it will close the butterfly or flap you see inside the carb making it idle lower.

 

[Unit 91]

it directly adjust the throttle wich is the idle it will close the butterfly or flap you see inside the carb making it idle lower.

Ok, I work at a Ford dealership. Fuel injection no problem... carb. yea I'm lost ha ha. Any thing else I should look at when I go out there? Another thing I noticed was that the throttle lever moves about 3 inches in travel. It only takes the first 1/2 inch and is at wide open throttle. And way to fix that?

 

[rocketkart]

I would need to see a video of that but im shore if there is somthing wrong one of us can help.

 

[Unit 91]

I would need to see a video of that but im shore if there is somthing wong one of us can help.

ill see if I can get a video of what I mean. kinda hard to see both sides at the same time but im sure I can figure something out

 

[Unit 91]

oh ment to ask, should choke be open or closed when im running the kart?

 

[rocketkart]

should be open/off.

 

[Unit 91]

I would need to see a video of that but im shore if there is somthing wrong one of us can help.

ok and open choke is when it runs up high rpms. ill try that idle screw and let you know how that works.

 

[rocketkart]

yeap let me know what you get.

 

[Doc Sprocket]

I must concur. It really does look like that screw is in waaay too far. It is indeed the idle speed screw, and if it's jacked right in, the machine won't idle no matter what you do. With the engine NOT running, use your finger to hold the throttle lever against it. Back it out until it will no longer reach the lever. Now, turn it in until it just cracks the throttle open.

With kart up against a wall or otherwise safely secured, start engine, warm, and open choke fully. If it stalls, turn screw in a bit more. If it idles TOO fast, back it out.

 

[Unit 91]

Ok, so it looks like you guys are on the right track too helping me. Went to adjust the screw and low and behold..... I find that the throttle does not actually close all the way to the stop. I took some pictures and some videos to try and show you what I mean. in picture you'll see where that valve sits.

In the second picture you'll see I was able to push it closed farther.

I also took some pictures of all the linkage to see if maybe you guys can pick up on something I don't know

Trying to find a way to upload the video to.

 

[Unit 91]

Video link #1 https://www.youtube.com/watch?v=ZwlaolQMWRc&feature=youtube_gdata_player

 

[rocketkart]

I see three option's you got. you can extend the linkage that goes to the carb and governor, or adjust the governor rod/stick and/or stretch out the spring just a lil that goes to the governor and throttle linkage.

or put some stort of return spring on the carb aka the ezy way. so 4 option's

 

[rocketkart]

check this if it is missing up anything on the carb, for it may be the reason that the carb is not closing all the way.

 

[Unit 91]

Now the other part, I questioned the lack of movement from closed throttle to wide open. If you watch you see what I mean. You can move the linkage two inches but it only uses 1/4 inch of movement to go from idle to w.o.t. http://www.youtube.com/watch?v=M3WtL1doURI&feature=youtube_gdata_player

 

[rocketkart]

yeah i'd but a return spring on the linkage of the carb and be done with it that should fix that. drill a small hole where the red dot is and put one end of the spring in it and the other to somthing to make it return like it should.

 

[rocketkart]

Now the other part, I questioned the lack of movement from closed throttle to wide open. If you watch you see what I mean. You can move the linkage two inches but it only uses 1/4 inch of movement to go from idle to w.o.t. http://www.youtube.com/watch?v=M3WtL1doURI&feature=youtube_gdata_player

thay all do that. when the engine is running the governor will make the carb close, so the more you pull the throttle the tighter the spring will got and that pull's the governor to open the carb.