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Post by barnie on Aug 13, 2011 12:23:34 GMT -5
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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Post by bhinch on Aug 13, 2011 14:43:50 GMT -5
Welcome....it might be your fuel filter....worth a shot...enjoy the ride...
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Post by harrywr2 on Aug 13, 2011 14:46:17 GMT -5
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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Post by leo on Aug 13, 2011 21:49:15 GMT -5
a belt that is too small will cause slow starts as will too heavy rollers.
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Post by mrpolymers on Aug 15, 2011 21:47:23 GMT -5
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...
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Post by TERRA NUVO on Aug 15, 2011 23:42:51 GMT -5
welcome barnie
I have no idea what it might be but good luck
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Post by tduhon48 on Aug 19, 2011 22:15:01 GMT -5
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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Post by edfr on Aug 19, 2011 22:26:52 GMT -5
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
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Post by ♣Luke♣ on Aug 20, 2011 11:02:13 GMT -5
that's a typical IAC problem. (idle air control)valve.
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Post by trailheadmike on Aug 20, 2011 12:23:51 GMT -5
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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