Is this a dirty carb issue?

2

2ball

Member
#1
#1
I start my minibike after letting it sit for 2 months. It started up and ran rough. The throttle had no effect on the bike. When I turned the throttle the engine rev stayed the same. I can see its not a throttle issue, the throttle latch on the engine moves and when I move it by hand I get the same result.

Also I used old gas last fill-up.

Does this sound like a gummed up carb issue?

If so so I take it apart and clean it or is there a gas additive or something Luke that to use?
 
The Restore Kid

The Restore Kid

New Member
#2
#2
You can see all of the parts moving on the motor? Even the throttle RITE ON The carburetor??

If it starts and idles.. And you hit the gas, and it sounds excatly the same, it sounds more like a spring fell off some where or something..

If it starts and ildes, then you hit the gas, and it starts chugging and sounds different, but won't accelrate, it is the carburetor loading up..

Is the choke on?? If you try to speed the engine up with hte choke on it will do that..

Could be bad gas.. drain it and try new..

Could be the float in the carb is bad and it's overflowing gas when it's not supposed to be..

Bad air filter, bad spark plug...

Could just be the carb is too rich and needs to be lened out some.. :shrug:
 
2

2ball

Member
#3
#3
I hoped this was going to be easy.

I could not tell the difference if the choke was all on or all off. Same thing happened no matter what the choke position.

Ill try new gas, air filter and plug.
 
The Restore Kid

The Restore Kid

New Member
#4
#4
I would just start with new gas.. leave the old stuff in there, and shake the shit out of it, to break loose any crap thats in there.. THEN dump it out..

Try new gas, and see what happens..
 
misfit

misfit

Member
#5
#5
What kind of motor are you looking at
It sounds like your running with a governor and you've lost a spring or piece of the linkage up to the carb. Try reving the motor using the throttle control on the carb itself, it turns the butterly inside open and closed.
The gas should be okay after sitting a couple months. Do you have a filter on your fuel line?

Only thing that makes sense to me is that the throttle on the carb isnt getting opened up.

Let us know on that motor....
 
2

2ball

Member
#6
#6
misfit said:
What kind of motor are you looking at
It sounds like your running with a governor and you've lost a spring or piece of the linkage up to the carb. Try reving the motor using the throttle control on the carb itself, it turns the butterly inside open and closed.
The gas should be okay after sitting a couple months. Do you have a filter on your fuel line?

Only thing that makes sense to me is that the throttle on the carb isnt getting opened up.

Let us know on that motor....
Click to expand...
Thanks for the help so far.

I have a new Coleman CT200U
CT200U Trail Mini Bike

It has a 6.5hp 196cc engine.

I'm not sure if I have a fuel filter
Maybe the fuel line is mucked up and not letting but a trickle of fuel in?

I pushed the throttle control on the carb and it had no effect just like when I turned the throttle on the handle bar.

A little more background, the last time it was ridden, my son said the throttle was not working right, and he kept pumping the throttle, until, all of a sudden, the engine reved high and the bike jumped forward. I rode the bike after that for about an hour with no issues. I put the bike away working good.

Probably not relevant, but when the bike was running I turned the fuel off and the bike went dead in about 5 seconds, but before it did, the bike reved high for half a second and cut off.

I hope to work on the bike tomorrow, so any suggestions on what to look for would be great.
 
misfit

misfit

Member
#7
#7
Just had a look at your bike online, it looks like it has a Predator motor.

Are you aware that the choke sticker on that motor is backward? Pushing the lever backward puts the choke on, forward is choke off.

If that doesnt help, pull your air cleaner off and look into the carb bore while working your choke lever. You may have a broken choke lever. If that appears to be working, open the choke so you can see past it, then turn the throttle control on the carb and look to see that the throttle butterfly is opening and closing inside the bore.

Try this and let us know....
 
2

2ball

Member
#8
#8
I fumbled around with the carb, I took it off and put it back on. The choke moves and the butterfly thing moves, but it seems to me there should be more movement, but I'm not sure. I put everything back together and now, it will start and run rough with choke opened, but it will not stay running when I close the choke.

What opens the butterfly? I see where the silver rod with the spring pulls on it, but should there be something where the throttle lever directly pulls on it?
 
paulhew

paulhew

New Member
#9
#9
Q:What opens the butterfly? I see where the silver rod with the spring pulls on it, but should there be something where the throttle lever directly pulls on it?
A:There is a linkage that connects the whole deal... follow the silver rod and spring back to where it all connects.

Try this:
Turn your gas tap off, remove your float bowl and clean it (one 10mm bolt), turn gas back on, check for fuel flow. Gas will dribble out of carb. Install float bowl.
 
Last edited:
2

2ball

Member
#10
#10
So the silver rod and spring are the only thing that open and closes the butterfly?

Is it like the throttle assembly where the rod opens it and a spring pulls it back closed?
 
The Restore Kid

The Restore Kid

New Member
#11
#11
Yes... sort of... The governor runs the butterfly... You pulling the throttle open, puts tension on the governor spring and pulls the governor open.. When engine gets up to speed, the governor pulls the throttle back shut, and keeps the engine at top speed.. The governor tells the engine how fast to run..

If the engine is not running, you should be able to hit the throttle, and the butterfly should go wide open, because the engine isn't running, and the governor has no power because the engine isn't running..

The governor feels how fast the engine is running, you merely get to suggest how far the butterfly goes open, the governor has the final say in how far it should be open...
 
2

2ball

Member
#16
#16
OK, so I pulled the carb off, sprayed it with card cleaner, put it back on and it works. Thanks for the help.

a few questions I have.

When the engine is off, the butterfly does not have full range of motion. when I look at it and move the throttle assemble, it only move from almost all the way opened to all the way opened. Is there something that happens, when the motor is running that closes the butterfly?

The engine is harder to start, before it would start no matter what the choke position, now it has to be started with the choke opened and has to warm up before closing the choke. Is there something wrong, or is it just that is is freezing when I am starting it now and it was summer before?
 
The Restore Kid

The Restore Kid

New Member
#17
#17
No, actually that sounds about rite.. :laugh: If it is all dialed in, it WILL BE a little bit lean when it's cold, because cold, the metal isn't warmed and swollen up, and everything isn't to it's running temp..

If you try adjusting that idle fuel thing like I mentioned.. That might help it start a little easier.. If you get more fuel to it on and idle, it will pull it easier when it's cold..

YOU GOTTA make sure to mess up the threads on it, so it doesn't fall out from being loose, but it helps quite a bit sometimes.. :smile:

The governor is what pulls the throttle shut.. when the engine is running.. Spinning weights inside the engine (governor) twists a rod, which pulls your throttle stuff back...

YOU are pulling on the throttle cable, trying to pull the throttle open, and you and that governor arm are fighting each other through the (governor spring)

The weights flying around, and the spring it's hooked to, are all balanced out, so the governor knows how fast to go.. :thumbsup:

when the engine isn't running, the governor has no power, and the spring is pulling the throttle open for you, so when you go to start it, the throttle is open some..

THEN when the engine starts, the governor takes over...

If all that is happening THAT'S GREAT!!! :laugh:
 
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