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Post by rickhun on Dec 17, 2012 8:54:15 GMT -5
I have a friend with a new sonny 150 3 wheel scooter ,only has 300 miles on it went one morning to ride and now wont run at high rpms , runs good at low idle and speed but it justs sputters at high rpms . we put new plug --no change---i took my carb. off put on his and same thing . we new to scooters someone please help 4cyle
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Post by scootnwinn on Dec 17, 2012 10:57:32 GMT -5
Did you already adjust the valves? Make sure your plug cap is fitting well too.
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Post by Deleted on Dec 17, 2012 11:32:33 GMT -5
Before you...
Well, no...
And you might get away with not having to adjust the valves now but I will say that AS you go diving into the cylinder head inspect closely around the carburetor intake manifold for air leaks, it is very possible she's sucking air as these scoots are famous for developing these....
Vacuum lines as well.
And while you're at it order up a gasket set (They run around $8 or so and cover one of every gasket you need) because the exhaust, the intake (both cylinder head to manifold AND manifold to carburetor), the tensioner, the cylinder head not to mention the valve cover, AND in some cases the transmission are ALL gaskets I've had to replace the first year.
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Post by 50cc on Dec 17, 2012 11:53:56 GMT -5
Sounds like too big of a main jet.
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Post by Deleted on Dec 17, 2012 12:00:31 GMT -5
Sounds like too big of a main jet. No, not unless someone has done modifications...  |
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Post by rickhun on Dec 17, 2012 12:40:26 GMT -5
No i have not checked valve adjustment ,will check that next.
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Post by scootercapecod on Dec 17, 2012 19:51:02 GMT -5
Before you... Well, no... And you might get away with not having to adjust the valves now but I will say that AS you go diving into the cylinder head inspect closely around the carburetor intake manifold for air leaks, it is very possible she's sucking air as these scoots are famous for developing these.... Vacuum lines as well. And while you're at it order up a gasket set (They run around $8 or so and cover one of every gasket you need) because the exhaust, the intake (both cylinder head to manifold AND manifold to carburetor), the tensioner, the cylinder head not to mention the valve cover, AND in some cases the transmission are ALL gaskets I've had to replace the first year. I agree with the intake or vacuum leak. Somewhere along the way it's just not getting enough airflow. I'd go with a cracked intake manifold or gasket. |
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Post by skuttadawg on Dec 18, 2012 0:51:37 GMT -5
For starters its still not broken in yet so be easy on it . After broken in it may go a lil faster with less friction than when its new and tight . When you say sputter is that like a lean misfire ? Remove the spark plug and look at its color to see how the jetting is and here is a chart to help you get an idea on how it is www.4secondsflat.com/plug_chart.htmlAny vacuum leak like if a hose came off or cracked will hurt top end . Most of us opt to replace the fuel lines and vacuum lines with automotive grade fuel lines since some have crappy ones that cause issues Did you use a NGK plug ? Checked the gap ? Most need the valves adjusted at 2,000 miles or so . When they get too tight it may get hard to or unable to start as well as stall when it gets warm . Some may not have the valves set right from the factory so would be good just to check them . Any autopart store sells the valve feeler gauges as they are bent on the tip Is the gas tank above the carb or one of those mounted in the floor ? If in the floor many stock fuel pumps can not deliver as much fuel as needed at high RPMs and a Mikuni pump is 30 or so A size or two larger mainjet can help sometimes |
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Post by rickhun on Dec 18, 2012 8:18:08 GMT -5
will check plug , the gas tank is below carb. remeber it only has 300 miles on it looks like a thousand lines i will check them.
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Post by rickhun on Jan 6, 2013 7:56:00 GMT -5
I have checked valves, they are right , changed plug, changed carbs, checked all lines , well im just puzzled, it will idle but when given gas it just skips dont know if its not getting enough gas or is it electrical  please help this is a sonny DF150TKB Would love to do away with the cal. emmisions on this thing. |
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Post by scootercapecod on Jan 7, 2013 16:22:25 GMT -5
I'm along with skuttadawg on this one. It seems like a fuel delivery issue but sometimes an intermittent short in the wiring that you plug into the CDI can cause that havoc as well, so it wouldn't hurt at least to give that a look over. As for the fuel issue if that turns out to be your trouble, make sure all lines are clean and sealing properly. Any leaks will and do cause issues
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Post by ce on Jan 7, 2013 17:20:45 GMT -5
Check all the wires to the CDI, coil, spark plug and ground. Usually the coil wires are loose, or the plug wire is unscrewed.
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Post by rickhun on Jan 8, 2013 7:28:03 GMT -5
I did notice that 1 wire coming off coil was loose ,so i tighten up , did not help
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Post by scootercapecod on Jan 8, 2013 8:54:10 GMT -5
Well, at least you eliminated future problems there so be thankful you did notice that. Meanwhile don't give up on it, I'm still thinking maybe weak fuel pump or a vacuum leak causing a lack of fuel flow. Check the intake manifold for any cracks or signs of wear, I'm willing to bet there's a break.
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Post by Deleted on Jan 8, 2013 10:29:56 GMT -5
I would remove the carburetor, the intake manifold, and the spacer.
Then put it all back together VERY carefully checking to make SURE she's NOT leaking air.
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Post by tvnacman on Jan 8, 2013 12:17:08 GMT -5
I would remove the carburetor, the intake manifold, and the spacer. Then put it all back together VERY carefully checking to make SURE she's NOT leaking air. While you have it off dump a cap full of gas in the hole and try to staty it . If it spudders or starts then your on to something . John |
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Post by wangchicken on Jan 10, 2013 2:46:12 GMT -5
i would consider changing a cdi i had one intermittently do similar thing, idle perfect ran OK and randomly run bad only at upper rpm,after i tested it and figured out it was the cdi ,i continued to run cdi until it completely failed ,which was about 50 more miles , service manuals are available on this site great reading material.
as with Chinese scooters some parts you will want to have on hand for when needed, i believe there is a thread on parts to buy .
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Post by rickhun on Jan 10, 2013 8:10:46 GMT -5
thanks i will look into all these things this weekend.
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please help this is a sonny DF150TKB Would love to do away with the cal. emmisions on this thing. 
