Throttle return spring

gabomoral

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Is my throttle return spring broken? Or damaged? Once i engage the plastic arm on the carburetor won’t return to its prevous position, leaving my engine on full throttle. First photo is its neutral postion, second photo is of the return spring, third photo is off the carburetor arm after i’ve engaged the throttle and it wont return (ALL THIS WHILE ENGINE IS OFF) I’ve removed the governor gear but left the governor arm so that i could use the stock throttle setup. I just turned it on and it seems to be returning but my engine is still on high rpms (ENGINE NOW ON). I dont have chain attached so i cant say if it’ll shoot out from underneath me but its very violent. Is this just normal engine action? My exhaust heated up in a matter of seconds. Im new to this stuff. Thank you for any feedback. Wish i could post a video of the throttle action. Engine also revs up on its own when i take it off choke. Is this normal?
 

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gabomoral

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Someone mentioned that the spring i mentioned only keeps the rod to the butterfly secure. They also mentioned that i should add a new robust spring to ensure the throttle returns. So fsr it does, but with a new added return spring will it ensure that my carburetor arm will return to neutral position after releasing the handlebar throttle
 

gabomoral

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Okay thanks for your help. I’ll go to homedepot or some other hardware store and look for springs. I’ll re-watch the videos to see where they attach em too. Still strange to me that the spring i mentioned only works when the engine is on. But i guess if it works then it works lol
 

Karttekk

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Someone mentioned that the spring i mentioned only keeps the rod to the butterfly secure. They also mentioned that i should add a new robust spring to ensure the throttle returns. So fsr it does, but with a new added return spring will it ensure that my carburetor arm will return to neutral position after releasing the handlebar throttle
See how it works once the spring is installed. The spring should go on the plate that moves when you throttle up, not the butterfly. Is the nut that holds down the throttle plate loose enough to let it return freely? Make sure the engine is off or the rear wheel or wheels are of the ground so the machine doesn't launch on you when you start it.
 

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gabomoral

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See how it works once the spring is installed. The spring should go on the plate that moves when you throttle up, not the butterfly. Is the nut that holds down the throttle plate loose enough to let it return freely? Make sure the engine is off or the rear wheel or wheels are of the ground so the machine doesn't launch on you when you start it.
The butterfly is what i’ve been calling the carburetor arm right? That plastic part on the carburetor that moves when you engage the throttle? Also yes i lossened the nut so it springs back nicely but i can tell that it could use another spring, like you said. If i get to it today, i will update today or whenever i get to it.
 

Karttekk

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The butterfly is the thin plate inside the carb with the black plastic plate with multiple holes in it attached to the top of it. I guess you could call it an arm. Your first picture with the thin spring on it is the butterfly. On the Manco karts I've restored, the factory pedal return springs are enough to pull the throttle closed as long as the throttle cable isn't binding anywhere and the engine throttle assembly is free. An additional spring on the engine can't hurt though.
 

gabomoral

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Okay yea so we talking about the same thing haha. Thanks for your help. Yea, engine on it works but i want that extra spring so im confident that my throttle will return each time so my bike doesn’t shoot out from underneath me
 

madprofessor

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You need 2 springs to really make it work right, both of them good and strong. That pathetic little spring with the throttle rod passing through it is worthless, only needed for the governor. You need a much tougher spring pulling back on the long manual throttle arm that your throttle cable's attached to. Hook one on anywhere you can.
The other spring needs to be at the other end of the throttle cable, ie; the gas pedal. You need a good strong spring pulling back on the gas pedal itself, and not just to supplement the spring at the other end. You do want the 2 springs to be plenty more than enough to absolutely guarantee the throttle on the carburetor will close down, for safety if nothing else. The problem with not having enough spring at the motor is that the pedal spring can cause a push on the cable that isn't met by a pull at the other end. The cable might jump out of a connection, or the cable conduit jump out of a holder at either end, or etc.
The obvious, but often unseen: Too sharp of a curve in a throttle cable can cause so much resistance to the cable sliding within the conduit that while your foot may be strong enough to pull the cable when pressing the gas pedal, the spring at the motor end can't return the cable when you let off. You should be able to push/pull an unattached cable just holding the end between your thumb and pinky finger. Shallow out any sharp curves. Fill the conduit with cable lube. Or get better cable/conduit set, ie; with poly lining of the conduit, not just the cheap hollow plastic tubing. You won't believe the difference that lining makes. And lube it anyway.
3/32" Dia Cable & Conduit for Go Karts & Mini Bikes | Go Kart & Mini Bike Parts | MFG Supply
Amazon.com: Liquid Wrench L711 Chain & Cable Lube - 11 oz. : Automotive
 

gabomoral

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You need 2 springs to really make it work right, both of them good and strong. That pathetic little spring with the throttle rod passing through it is worthless, only needed for the governor. You need a much tougher spring pulling back on the long manual throttle arm that your throttle cable's attached to. Hook one on anywhere you can.
The other spring needs to be at the other end of the throttle cable, ie; the gas pedal. You need a good strong spring pulling back on the gas pedal itself, and not just to supplement the spring at the other end. You do want the 2 springs to be plenty more than enough to absolutely guarantee the throttle on the carburetor will close down, for safety if nothing else. The problem with not having enough spring at the motor is that the pedal spring can cause a push on the cable that isn't met by a pull at the other end. The cable might jump out of a connection, or the cable conduit jump out of a holder at either end, or etc.
The obvious, but often unseen: Too sharp of a curve in a throttle cable can cause so much resistance to the cable sliding within the conduit that while your foot may be strong enough to pull the cable when pressing the gas pedal, the spring at the motor end can't return the cable when you let off. You should be able to push/pull an unattached cable just holding the end between your thumb and pinky finger. Shallow out any sharp curves. Fill the conduit with cable lube. Or get better cable/conduit set, ie; with poly lining of the conduit, not just the cheap hollow plastic tubing. You won't believe the difference that lining makes. And lube it anyway.
3/32" Dia Cable & Conduit for Go Karts & Mini Bikes | Go Kart & Mini Bike Parts | MFG Supply
Amazon.com: Liquid Wrench L711 Chain & Cable Lube - 11 oz. : Automotive
FYI i got a minibike but i added the spring anyways. I noticed that the butterfly returns more but not completely, leaving the engine still revving. If i manually push the butterfly to idle (while off choke) the engine just stops running and turns off. Second photo is where I manually push the butterfly to, so it can idle, but instead if turns off.5F880AA4-A70B-4BE7-8D71-CC2A914E3359.jpeg
 

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gabomoral

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Good idea. As always, safety first!
i added the spring. I noticed that the butterfly returns more but not completely, leaving the engine still revving. If i manually push the butterfly to complete idle (either on choke or off) the engine just stops running and turns off. Second photo is where I manually push the butterfly to, so it can idle, but instead if turns off.
 

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madprofessor

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Oops! The new spring is keeping it from returning all the way. It's too big for the space you have it in, it's completely contracted and acting as a block to the lever moving any further. Would have quit pulling on the arm even before it got to that state, no wonder it's not pulling the carb closed.
Either find somewhere else to hook it up so it's in a stretched state at all times, even at idle, or..............Release the spring from one end or the other and cut some of it off. Then pull the new end out into a hook shape to reattach it.
EDIT: That black screw the "butterfly" bumps into the tip of when you force it closed, that's your idle screw. Screw it in further to raise your idle speed.
 

gabomoral

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Oops! The new spring is keeping it from returning all the way. It's too big for the space you have it in, it's completely contracted and acting as a block to the lever moving any further. Would have quit pulling on the arm even before it got to that state, no wonder it's not pulling the carb closed.
Either find somewhere else to hook it up so it's in a stretched state at all times, even at idle, or..............Release the spring from one end or the other and cut some of it off. Then pull the new end out into a hook shape to reattach it.
EDIT: That black screw the "butterfly" bumps into the tip of when you force it closed, that's your idle screw. Screw it in further to raise your idle speed.
I got the smaller spring and replaced it. Also added a new one to the arm that connects to carb butterfly to make sure it always shuts. But im starting to think i just have a faulty carb or something. Its a brand new engine but now it wont even idle off choke. Theres no way the carb is dirty or blocked by debris. On choke it idles fine. Great even. Its not revving up by itself or anything but once I take it off choke it dies unless im engaging the throttle which means if i release throttle so it can idle… it dies. I was planning on eventually getting a mikuni carburetor anyways. You think its a carb issue? Or something internal? At this point im out of ideas except “new carb”. Do i have the wrong idea of how the carb/butterfly works?
EDIT: i feel like its something miniscule but necessary and I'm just failing to realize. Also i been reading about too lean or too rich but on the tillotson 212 carb in not sure how to adjust that or if i need to
 
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madprofessor

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Humor me on this one.............pull off the air filter so that you can see down the throat of the carburetor, and actually see what is actually the "butterfly" inside there. Look at this video at the point where the timer is at 1:25 (1 min., 25 sec.). You'll see the actual butterfly, what they're labeling the "throttle plate", twisting open/shut.............How the Small Engine Governor Works - YouTube..............
You sure yours is opening when you give it throttle without the choke being turned on? Wouldn't be the first time somebody got confused and got that backwards after the little factory sticker's gone missing that shows which way is which. (Talking about myself.)
 

gabomoral

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Humor me on this one.............pull off the air filter so that you can see down the throat of the carburetor, and actually see what is actually the "butterfly" inside there. Look at this video at the point where the timer is at 1:25 (1 min., 25 sec.). You'll see the actual butterfly, what they're labeling the "throttle plate", twisting open/shut.............How the Small Engine Governor Works - YouTube..............
You sure yours is opening when you give it throttle without the choke being turned on? Wouldn't be the first time somebody got confused and got that backwards after the little factory sticker's gone missing that shows which way is which. (Talking about myself.)
Okay i did more investigating. So like you said i looked down the shaft and yes the butterlfy (the actual butterfly) is opening and closing. I even turned the engine on and checked. On choke/run when the butterfly is closed completely the engine wont turn on/dies. This is normal? I noticed that when the butterfly isn’t completely closed my engine will stay on, choke or run. But on run it will just constantly rev even though im looking down the shaft and seeing the butterfly almost closed. And when i do push the butterfly to s more closed position so the engine can calm down, it dies. i know for a fact its not hiting idle cause it does so on choke and i tell by the noise difference on run that my engine definitely isn’t idling even with butterfly almost closed

Pictures if it opening and closing

i dont think i assembled the etube and jet incorrectly. I followed gopowersports instructions. Small diameter of the etube in first, the jet, screw it in. All of that.
I really appreciate you answering my questions (i know there are alot)
 

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madprofessor

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On choke/run when the butterfly is closed completely
Not sure what you're saying. Factory sticker by the intake would say choke/run. Arrow or similar would show which way to move the lever for choke, and which way for run. In choke position the butterfly would close completely and stay that way. In run position the butterfly would be closed most of the way at idle, but would open all the way as you give it throttle.
That's what I was asking, if you're turning the lever the correct way to choke it, and the correct way to run it, or have that backwards. The airbox with that factory sticker on it on a couple of engines I've hotrodded got thrown out, so there wasn't that simple thing to look at to be sure I didn't move the lever backwards of my intentions.
So one time I was having trouble making an engine run without being choked like the trouble you have, and it turned out I was short on coffee and common sense, was setting the lever to choke when I thought it was on run, and vice versa.
 

gabomoral

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Not sure what you're saying. Factory sticker by the intake would say choke/run. Arrow or similar would show which way to move the lever for choke, and which way for run. In choke position the butterfly would close completely and stay that way. In run position the butterfly would be closed most of the way at idle, but would open all the way as you give it throttle.
That's what I was asking, if you're turning the lever the correct way to choke it, and the correct way to run it, or have that backwards. The airbox with that factory sticker on it on a couple of engines I've hotrodded got thrown out, so there wasn't that simple thing to look at to be sure I didn't move the lever backwards of my intentions.
So one time I was having trouble making an engine run without being choked like the trouble you have, and it turned out I was short on coffee and common sense, was setting the lever to choke when I thought it was on run, and vice versa.
Double checked and im sure its on run. I have the default air filter laying around so i made sure. When the plastic arm attached to the butterfly hits the idle screw (wether its screwed fully in our slightly out) it dies. Thats whats making me question the quality of the carb. Unless im wrong and its not supposed to rest on the idle screw. But then she’ll rev and rev when she’s not resting on the idle screw. Sometimes it’ll slow down but generally its just revving. I think at this point im going to wait till I receive my chain and i’ll see how she runs.
 

madprofessor

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Throttle lever, arm, tab, whatever you want to call it on the carb should definitely stop in contact with idle screw, that's how idle gets set faster/slower. You screw it in to idle faster, out to slow it down.
 
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