Jmstar 150cc scooter shuting off

BigWill · 07-13-2010, 09:31 AM

well the jmstar scooter i have was real nice. Until it started shutting off while rideing it. i would start it up then give it some throttle and it would just bog out and shut off any suggestion i would appriciate it. :(

Cal25 · 07-13-2010, 10:00 AM

do you know if it is getting spark and fuel?

Weldangrind · 07-13-2010, 12:18 PM

Welcome!

That sounds like the stock spark plug. Have you tried a new NGK?

Reveeen · 07-22-2010, 09:37 AM

Sounds like a fuel "issue", but as was suggested, pull the plug (noting the colour) and replace it with an NGK.

Usually the plug colour will tell the tale and give you a direction to head in.

These scooters have some, well, kind of built-in problems:

The fuel/vacuum lines are made out of garbage. Try replacing all with quality stuff (being careful doing 1 at a time).
With the fuel tank under the floorboards in order to give you under seat storage, there is a vacuum operated fuel pump that can give trouble, so give it a look/test. These are non-rebuildable, replace only specimens, that will gum up (if fuel is allowed to dry in them), and stop working/working well.
The electric chokes affixed to the carburetors seem not to have a long life, and if stuck closed, can give you the trouble you describe (check plug colour). You can use an ohm meter, checking for 12V (with the key on running), and continuity (resistance) unplugged from the harness, they do sometimes "stick" internally, there is no test for this, only replacement.
If stored for a long time the carb will "gum up". carefully remove the float bowl and clean out everything with carb cleaner. There is a formed "O" ring on the bowl, that will immediately shrink, so running hot tap water over it (and GENTLY stretching it) will allow it's re-use.

General *thought* from around the different forums is that the carb can start giving trouble within 500 miles on these bikes, and they recommend replacement. Though none seem to advise replacement with what (all Chinese scooters seem to use the same carbs, so I have no idea what you would use to retain the existing features).

Cal25 · 07-22-2010, 10:42 AM

Great information there. thanks!

07-13-2010, 09:31 AM	#1
BigWill Join Date: Jul 2010 Posts: 1	Jmstar 150cc scooter shuting off well the jmstar scooter i have was real nice. Until it started shutting off while rideing it. i would start it up then give it some throttle and it would just bog out and shut off any suggestion i would appriciate it. :(
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07-13-2010, 12:18 PM	#3
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	Welcome! That sounds like the stock spark plug. Have you tried a new NGK? __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
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07-13-2010, 10:00 AM	#2
Cal25 Join Date: Feb 2008 Location: Terrell and Grapevine Tx. Posts: 1,585	do you know if it is getting spark and fuel?
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07-22-2010, 09:37 AM	#4
Reveeen Join Date: Jun 2009 Location: orbital platform Posts: 741	Sounds like a fuel "issue", but as was suggested, pull the plug (noting the colour) and replace it with an NGK. Usually the plug colour will tell the tale and give you a direction to head in. These scooters have some, well, kind of built-in problems: The fuel/vacuum lines are made out of garbage. Try replacing all with quality stuff (being careful doing 1 at a time). With the fuel tank under the floorboards in order to give you under seat storage, there is a vacuum operated fuel pump that can give trouble, so give it a look/test. These are non-rebuildable, replace only specimens, that will gum up (if fuel is allowed to dry in them), and stop working/working well. The electric chokes affixed to the carburetors seem not to have a long life, and if stuck closed, can give you the trouble you describe (check plug colour). You can use an ohm meter, checking for 12V (with the key on running), and continuity (resistance) unplugged from the harness, they do sometimes "stick" internally, there is no test for this, only replacement. If stored for a long time the carb will "gum up". carefully remove the float bowl and clean out everything with carb cleaner. There is a formed "O" ring on the bowl, that will immediately shrink, so running hot tap water over it (and GENTLY stretching it) will allow it's re-use. General thought from around the different forums is that the carb can start giving trouble within 500 miles on these bikes, and they recommend replacement. Though none seem to advise replacement with what (all Chinese scooters seem to use the same carbs, so I have no idea what you would use to retain the existing features).
	0

07-22-2010, 10:42 AM	#5
Cal25 Join Date: Feb 2008 Location: Terrell and Grapevine Tx. Posts: 1,585	Great information there. thanks!
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