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May 23, 2013, 5:04am

ScootDawg Scooter Forum :: The Garage :: 250cc Scooters and up.... :: hesitation from stop light

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Topic: hesitation from stop light (Read 422 times)

barnie
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hesitation from stop light
« Thread Started on Aug 13, 2011, 12:23pm »

have a jcl mp250a that starts fine/idles fine/runs at higher speeds just fine but has a hesitation/bog down starting from stop
thru about 2500 rpm (acts like an unsteady fuel supply then as you get up to about 35 mph seems to run just fine, valves and fuel air screw are all good. checked needle and diaphram in carb and all are good. if i give it a good shot on the throttle it goes ok, but if u want to run at slower speed it seems starved for fuel. think i need to clean carb?? your help appreciated. barnie

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bhinch
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Re: hesitation from stop light
« Reply #1 on Aug 13, 2011, 2:43pm »

Welcome....it might be your fuel filter....worth a shot...enjoy the ride...

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harrywr2
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Re: hesitation from stop light
« Reply #2 on Aug 13, 2011, 2:46pm »

Aug 13, 2011, 12:23pm, barnie wrote:

think i need to clean carb?? your help appreciated. barnie

Sounds like a lean bog. I'd inspect your airbox for cracks and if none are found move on to cleaning the carb.

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leo
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Re: hesitation from stop light
« Reply #3 on Aug 13, 2011, 9:49pm »

a belt that is too small will cause slow starts as will too heavy rollers.

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mrpolymers
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Re: hesitation from stop light
« Reply #4 on Aug 15, 2011, 9:47pm »

Barnie,

I had a similar problem about a month ago. I also, have a JCL MP250A scooter. Poster Leo I think has placed his finger on it. I had a problem from a stop not getting much acceleration. I too, thought it was a carburetion issue. Well, I decided to check my variator and roller weights. Turns out, one of my doctor pulley weights was damaged and I had a broken fin in the variator. It was not allowing the variator to close properly until I had the throttle wide open for a time to achieve the proper RPM. Replaced with a new variator and new weights.. Runs better now then it did with the Dr. Pulley weights. Check the variator...

« Last Edit: Aug 15, 2011, 10:03pm by mrpolymers »

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TERRA NUVO
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Re: hesitation from stop light
« Reply #5 on Aug 15, 2011, 11:42pm »

welcome barnie

I have no idea what it might be but good luck

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tduhon48
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Re: hesitation from stop light
« Reply #6 on Aug 19, 2011, 10:15pm »

have you changed out you fuel lines and air lines.. the lines that come on these scooters are cheaply made and result in vacuum leaks and fuel leak causing lack of power on start up

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edfr
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Re: hesitation from stop light
« Reply #7 on Aug 19, 2011, 10:26pm »

You answered your own question, saying if you give it a good twist on the throttle it goes ok.
Up to those speeds your mostly running off the PILOT JET.

You Fuel Ratio screw is not adjusted correctly. Now it is hard to tell if your running rich or lean at low rpms.
But just put it on the Center Stand and First turn the Fuel Ratio Screw 1/4 Counter CLockwise(RICHEN IT). Then twist the throttle like you do when you experience the bog. If it is Worse then Turn it CLOCKWISE(LEANER) 1/2 turn and try it again. If it gets better or it goes away your done. You may need another 1/8-1/4 turn once you put a load on it, so take the screwdriver with you.
Lefty

« Last Edit: Aug 19, 2011, 10:29pm by edfr »

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♣Luke♣
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Re: hesitation from stop light
« Reply #8 on Aug 20, 2011, 11:02am »

that's a typical IAC problem. (idle air control)valve.

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trailheadmike
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Re: hesitation from stop light
« Reply #9 on Aug 20, 2011, 12:23pm »

Work up from the small things before you start taking apart the carb, etc. I'd start with Lefty's suggestion - first properly adjust the carb to see if that cures the problem.

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