Start cold engine with a little throttle By gingel (Read 936 times)

[gingel]

Hi,

When my scooter engine is cold (even if it's only off for 30-60 mins),
and i start it, i have to give a little throttle so it will start, after that it's running.

When engine is warm, then i only have to push the starter, without throttle.

Is it normal? Can i do something about it?

Thank you.

[Bashan]

Have you set your valve gap? That's usually what causes those symptoms. But some of them are just hinky like that too. Rich

[Alleyoop]

When in that time the ENRICHER has already retracted so it is then running a little on the rich side even though the motor has not completely cooled off. So try Leaning out the Fuel Ratio Mixture try it 1/4 Clockwise at a time and see if it starts better when NOT completely COLD. Opening the throttle a little at that point is only letting more air to be sucked in to match to much fuel.
Alleyoop

[gingel]

If i'll lean the mixture, what will happen when the engine is completely cold?
Should it start without throttle?

Now when it's completely cold, i also have to give a little throttle.

The valves were checked.

Thank you.

[Alleyoop]

Yes it should start without throttle if all is functioning correctly. It could also be the IDLE is set to low. To low means the Butterfly is closed to much covering up the tiny Pilot jet holes that suck the fuel from the Pilot Jet. As you open the throttle just a little it uncovers more of the tiny fuel holes so it sucks more fuel plus a little more air.
Alleyoop

[gingel]

I just want to mention that i have this scooter a few years, and i always had to give
a little throttle after the engine was a little cold.
But now i installed a new carburetor, so i thought maybe this thing will also be solved.

The idle is now about 1700-1800 RPM when engine is warm.
I guess i can open the idle screw a little, but then the idle RPM will be
faster when warm.

I will try to lean the mixture, and see what happen.

The scooter is 125cc 4T.

Thank you.

[gingel]

So i tried to lean the mixture (turned the mixture screw Clockwise almost 1/2 a turn),
but it's the same.
More than 1/2 Clockwise, and the engine start to sound not good.

So i guess this is how this scooter. i read that there are scooters that need
a little throttle when starting.

About the idle RPM, is 1700-1800 ok for 125cc motor?

Thank you.

[Alleyoop]

The Idle you set it to where you can get the smoothest Idle out of it. anywhere from 1500-1800 is usually where they will idle, Just as long as your REAR WHEEL is not spinning fast otherwise you will have to hold the brake when your stopped.
Alleyoop