Scooter starts and runs, but won't idle? By aggressor2790 (Read 3,671 times)

[aggressor2790]

What's up, guys? I've been reading these forums for a bit and decided to make an account.

Little bit of background info: I have 2 Taotao Atm-50cc scooters. Both have around 500 miles on them.

I tipped one over on its side going maybe 10mph, and it lost a lot of power. I tried everything. New carb, checked all connections and wires, checked vacuum lines, etc. I noticed that my battery wasn't keeping a charge after the crash, so I figured it had to be something with the stator. I took the flywheel off, etc, and noticed that one of the coils were damaged.

Then I took the stator, flywheel, etc off of the running scooter, put it on the messed up scooter and couldn't find my keys . So, I THEN put the messed up stator on the working scooter to see if I'd get the same symptoms (bogging under gas, extreme loss of power, dying battery.) I did, so I took the bad stator off and put the working stator back on the working scooter.

After that the working scooter continued with the same problems that the other scooter had. I took the flywheel back off and noticed that the woodruff key was gone. I ordered some and put it on. It now runs good, but it won't idle. :\

Things I've tried:

Put another stock carb on the scooter, still does nothing.

I've even adjusted the valve clearance. They were both pretty tight, so I set them both at .004. Still no idle. :\


Anything else that I'm missing here?

[aggressor2790]

Any ideas at all, guys?

I replaced the auto-choke, petcock and lines, carb, ect.

I should also mention that the battery has gone completely dead. No lights or anything, except when it's running. Still won't idle.

I put the idle screw all the way in, and it will idle for maybe 10 secs now, but then cuts off.

[aggressor2790]

I went out to take it around the block before playing around with the carb some more, and now when I have it at wide open throttle, the rpms drop down to idle, then rev back up to wide open throttle. It'll keep doing this as long as I have the throttle all the way back. It will barley go up a hill because of this.

I'm about ready to give up. :\

Can anyone please help?

[aggressor2790]

Was riding around the block, reached down to mess with the carb, and it shocked the crap out of me??

What the hell is up with that?

[alleyoop]

Ok, have you checked for AIR LEAKS, the intake manifold could be cracked or the Air Tubing and or the air box. The symptoms rpms going up and down is a VERY LEAN CONDITION. Not enough gas is being sucked into the motor.

So time to adjust the FUEL RATIO MIXTURE on the carb. And here is how to do that:
Alleyoop


If your carb has a SCREW near the INTAKE MANIFOLD side the Carb has a FUEL RATIO MIXTURE Adjustment screw.

Turning the Fuel Ratio Mixture Clockwise LEANS it Turning it Counter Clockwise RICHENS it.

The Idle Speed screw is on the Throttle Control Wheel that the Throttle Cable pulls on. The Idle Speed Screw usually has a SPRING under it to keep the setting. Turning that Clockwise RAISES the Idle and Turning it Counter Clockwise LOWERS the Idle.

Most of your 250+ scoots come with 30+ mm Carbs. The procedure is the same just that the Fuel Ratio Mixture Screw may be in a Different place. They also have a ACV Valve that looks like a flying saucer attached to the front top of the carb. Other Carbs usually have them on the right side by the Throttle bracket.

[red]IF YOUR CARB HAS A SCREW ON THE AIR FILTER SIDE GO SEE 2TS CARB TUNING.[/red]

[red]Follow this procedure to tune the carb: Take your time 1/4 turn to much in either direction makes a big difference.[/red]

ADJUSTING YOUR FUEL RATIO MIXTURE:









[red]YOU WANT THE HIGHEST RPMS OUT OF THE AIR RATIO MIXTURE SCREW:[/red]

Start your scoot and Get The Engine Nice and Hot about 5 minutes so that the Enricher IF it has one is no longer Allowing Extra Fuel to come in. Then do the following to fine tune the Fuel Ratio Mixture:

[blue]FUEL RATIO SCREW:[/blue]

FIRST TRY RICHENNG THE FUEL MIXTURE FROM ITS CURRENT SETTING:

1. [red]RICHEN THE FUEL RATIO MIXTURE:[/red]

Turn the Fuel Mixture Screw COUNTER CLOCKWISE 1/4 of a turn and wait 10 seconds to let the engine catch up with the new setting.

a. If the RPMS go up REPEAT #1 UNTIL the RPMS GO DOWN OR NO CHANGE(then go to b).

b. TURN the Fuel Ratio Mixture Screw CLOCKWISE 1/8 and that should be your highest Fuel Ratio Mixture setting—GO TO #3.


[green]******[/green]If on the FIRST 1/4 TURN from the STARTING Position IN #1 ABOVE the RPMS GO DOWN OR NO CHANGE , turn the Fuel Ratio Mixture Screw Back the 1/4 turn to the Starting position and wait 10 seconds until the engine catches up -- GO TO #2[green] ******[/green]


2.[red]LEAN THE FUEL RATIO MIXTURE:[/red]

Turn the Fuel Mixture Screw CLOCKWISE 1/4 of a turn and wait 10 seconds to let the engine catch up with the new setting.

a. If the RPMS go up REPEAT #2 UNTIL the RPMS GO DOWN OR NO CHANGE(then go to b).

b. TURN the Fuel Mixture Screw COUNTER CLOCKWISE 1/8 and that should be your highest Fuel Ratio Mixture setting—GO TO #3.


[red]IF YOU GOT TO THIS POINT AND NOT INSTRUCTED TO GO TO #3 THAT MEANS THERE WAS NO CHANGE IN RPMS FROM DOING #1 or #2 ABOVE, IT IS TIME TO CLEAN THE CARB:
YOU NEED TO CLEAN YOUR PILOT JET AND PASSAGE AND AIR PASSAGES AND THEN START FROM #1 AGAIN.[/red]

3. [blue]IDLE SPEED SCREW:[/blue]

The Idle Speed Screw on a Carb that are on most 4Ts you will find on the right side on the THROTTLE CONTROL WHEEL. It is the screw with a SPRING on it.
To Lower the IDLE you turn it COUNTER CLOCKWISE to Raise the IDLE you turn it CLOCKWISE.

If after adjusting your Fuel Ratio Mixture your idle is to fast Turn the IDLE SPEED SCREW COUNTER CLOCKWISE. For the 50s-150s they like to idle around 1500-1800rpms, for the 250s+ they like to idle from 1800-2000 rpms, pick the smoothest idle with the rear wheel not spinning ---GO TO #4.

4. [blue]TEST YOUR ADJUSTMENTS:[/blue]

Now give the Throttle a QUICK twist and the RPMS should climb up quickly without hesitation or bogging and come down to where you set your Idle at---GO TO #5.

5. NOW take a ride and try it out, the Fuel Ratio mixture may need a tweak in either direction now that the motor has a load on it.

The tweak will be minor maybe a ¼ turn richer or leaner IF it acts up with a load---GO TO #6

6. When it acts up BACK OFF the throttle about ¼ of an INCH AND HOLD IT THERE:

a. If the motor speeds up it is LEAN you need to richen it up a little.

b. If the motor settles down and or stumbles and then settles down it is RICH you need to LEAN it out a little.
GO TO #5 AGAIN.

[blue]Problems with the IDLE:[/blue]

1. Give the throttle a quick twist:

A. If the rpms drop below idle speed, then recovers (or stalls), it is RICH —Turn the Fuel Mixture Screw Clockwise ¼ turns at a time and go to #1.

B. If the rpms do not drop quickly to the idle speed but hang and drop slowly it is LEAN —Turn the Fuel Mixture Screw Counter Clockwise ¼ turns at a time and go to #1.

[aggressor2790]

I've checked for air and vac leaks yesterday, but never saw anything. I even checked the gasket at the intake. All seems fine. I also spent hours messing with the carb, but it's still the same I'll give the carb another shot, though.

[aggressor2790]

Quick question. Would the stator and flywheel cause a problem like that? I know it doesn't make sense, but all these problems started when I took the flywheel off to change the woodruff key.

I also have the same exact problem going on with my other scooter, which started after I took a fall. The scooter fell on the right side, and guess what's on the right side....Flywheel and stator.

Just seems a little weird. Could it have anything to do with timing since I messed with the flywheel?

[aggressor2790]

Another bit of important info: When idleing, if I give it some gas, the rpms are hesitant to come back down, unless I hit the back brakes, or wait a while. It also has surges of rpms. It'll just be sitting there, and almost take off without me hitting the gas.

[aggressor2790]

I followed the directions for adjusting the carb, but it still does the same thing.

[alleyoop]

Well something is wrong with your CARB or the PILOT JET is clogged and its passage.

RE-READ the tuning procedure, PROBLEMS WITH IDLE, THE LAST SENTENCE B. That is what happens it is LEAN so your fuel ratio mixture is not working.

Take the carb off and check the FLOAT it may be stuck or because of the fall it may have got out of adjustment and or is binding and not filling up the bowl to its correct level.

Adjust the float like this:


Alleyoop

[aggressor2790]

The carb I have on there is pretty much new. :\

[alleyoop]

How many turns out is the Fuel Ratio Mixture?

Doesn't matter if new or whatnot, the scoot fell over and caused something to be out of whack. Does the throttle linkage return back quickly or maybe that is hanging up.

TAKE A PIC OF THE CARB AREA.

Alleyoop

[aggressor2790]

I'll check on all of that for you in a bit. No phone with camaera on me right now. I'll have one around 5. The throttle cable is fine, though.


Edit: The carb that was on the scooter isn't on there anymore. I took that off the day after the crash thinking that was the problem. The one I have on there now is a stock carb I had sitting around. It's pretty much brand new.

[alleyoop]

Well turn the fuel ratio screw clockwise until it stops and count the number of full turns it took to stop. I can truthfull tell you that sucker is running LEAN AND MEAN.
Your not running it without an air filter are you. It is either getting to much air or not enough fuel.

Ok bud talk at you later on this afternoon we will get it straightened.
Alleyoop

[aggressor2790]

I took the air filter out yesterday to check and see if anything was clogged. Haven't put it back in yet, but it was doing that before I took it out.

Never had one in the other scoot, though.