Kymco Miler 125 throttle problem - please help.

[pichulec]

Hello everyone. I recently bought of my friend scooter Kymco Miler 125. Scooter hasn't been used for long time (last time started a year ago). Replacing battery, which was the initial problem has been sorted out now, but after yesterday's ride I've noticed throttle problem. On certain positions of throttle (1/4 twisted mostly), when I twist it and hold it, engine not responding for a few seconds. After that when i keep holding throttle on the same position engine start responding. Mostly on full throttle engine responding without any problem. Described problem happening mostly on low rpm (1/4 TWISTED THROTTLE -  under 4 - 5k RPM). Yesterday I stopped in the middle of roundabout twice because of no power. In my opinion cleaning the carburettor should help, but I don't have much experience in motorbikes so I am asking here. Any help will be appreciated

[pipster326]

Did you try adjusting the throttle cable? I would try that before I tore into the carburetor


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[pichulec]

I forgot to add there might be a water in the tank, because in first day, when i bought the scooter i twisted key in wrong side and didn't know that I opened fuel tank (left overnight - it was raining). So if you get all together it must be carburetor. It's very unlikely that is a throttle cable because when i twist and hold, after few seconds in this position engine reacting.

[mrbios]

Your pilot jet is clogged.  The pilot is a "ramp" to the main jet and when clogged does exactly what you describe. 

Resolution:

1. Pour a 1/4 of a bottle of 91% rubbing alcohol in your gas tank or do the same with isopropyl alcohol from Walmart or the auto store.  It will dissolve the water and it will be burned up with the gas.  It is not likely to be causing a problem as water floats on top of the gas and gas flows from the bottom of the tank to the engine.  It is still good to remove it because water will rust a metal gas tank which many scooters have.  Also, bacteria lives in the water and can produce a slimy waste product that can clog jets. 

2. Watch my videos which clearly explain basic carb theory and cleaning.  The videos will show you why the clogged pilot jet is the most common issue.

Carburetor Cleaning Part I   
Carburetor Cleaning Part II   
Carburetor Cleaning Part III   

[pichulec]

1/4 of how big bottle?  Fuel tank is 9 litre,  at the moment half full

[CROSSBOLT]

Gasoline is lighter than water so the water will be at the bottom. Water=8 lbs/gal; gas=6lbs/gal.

Karl
 

[Mr. Paul]

Clogged pilot jet was my first thought also.

[mrbios]

Gasoline is lighter than water so the water will be at the bottom. Water=8 lbs/gal; gas=6lbs/gal.

Karl

Thanks Karl. 

[mrbios]

1/4 of how big bottle?  Fuel tank is 9 litre,  at the moment half full

Basically, a few ounces should be fine.  If you buy that actual product it should provide more information. 

[pichulec]

The main question is how much water get in to tank. If large amount none of those will help...

[pichulec]

After adding 1/4 bottle of redex to fresh fuel, looks like problem it's getting sorted by itself. After one ride throttle reacts much better (nearly no problem) and bike have more power, engine runs smoother. Probably after a while problem will go Thx for help guys.

[pichulec]

After some time of testing I can say the problem is still coming back - but with the difference - now coming back only when the scooter is cold. Looks like I will have to clean the carburetor eventually..