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Post by jersey on Oct 5, 2013 22:16:49 GMT -5
Hi everyone,
I have a 2012 Jonway YY150T-12 150cc scoot with 3100 miles. The other day I was riding along and it started sputtering and surging. I pulled over and it died. I turned around and made it home 2 miles, sputtering and surging the whole way. Now, I can get it to start if I open the throttle slightly and hit the starter, and it will stay running (sputtering terribly) if I keep the throttle open. What could be causing this?
Things I've tried: checked and gapped spark plug. Replaced coil. Switched back to old CDI (bike uses AC CDI). Checked fuel flow just after the petcock (on carb side) and flow is good. Checked in air box and don't see anything that could be restricting airflow, even started it w/ box open and sputtered as before. Did a visual check of vacuum lines and didn't notice cracking, etc (but there are some old lines on there so I'll replace those next)
At this point I suspect something in the carb, but isn't it strange that something would seem to be affect BOTH the idle jet and main jet? That they would BOTH clog at the same time? Honestly tho I don't have much experience with carbs so someone tell me otherwise.
Thanks for any help.
Aubry
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Post by alleyoop on Oct 5, 2013 22:26:23 GMT -5
First thing you want to do is ADJUST your valves. Set them both to .004 inchs and see if that fixs the problem.
Alleyoop
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Post by shalomdawg on Oct 5, 2013 22:36:45 GMT -5
howdy, i'm not a mechanic so my suggestion is just conversation but that sounds like a high tension system problem to me. that would be from the coil or cdi to the plug.
lotsa miles and smiles to ya
ken
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Post by gearhead on Oct 5, 2013 23:00:30 GMT -5
So ya, I had the same problem and now my scoot is out of commission. I think the valve adjustment is the correct thing to do (I will tell you for sure tomorrow). If you fix other things and it stops surging but is running rough, it could be a deeper problem with your timing. I would suggest adjusting valves, fuel/air screw, and seeing how it runs. Valves are probably the number 1 reason scoots sputter after the Carb's anyway.
Good luck and let us know
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Post by alleyoop on Oct 6, 2013 0:51:01 GMT -5
Surging is a sign of running very LEAN, but before messing with the Fuel Delivery lets get the Valves adjusted first because if they are tight then adjusting anything else is just compensating for tight valves. If you adjust the fuel delivery first with tight valves then when you do adjust the valves then you have to re-adjust the fuel delivery again.
Alleyoop
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Post by pmatulew on Oct 6, 2013 7:07:14 GMT -5
You got smilied so not sure how many miles that was. but if it's been quite a few, and it hasn't been done already, then it would be worth your while to adjust the valve clearance. Then I would definitely go after those vacuum lines. Even if they look okay they could be leaking and throwing the mixture all off. Get yourself a fist full of baby zip ties to replace the spring clamps and cinch down all the hose connection points.
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Post by jersey on Oct 6, 2013 17:55:17 GMT -5
Ok, I neglected to mention I adjusted the valves about 130 miles ago, set both to 0.004 inches. I can check the clearances again, just to be sure though.
I replaced the vac lines that were original, so now there are no original fuel or vac lines on the scoot. Problem persists.
Ha, and just to make it more fun, now for some reason my seat is locked down and will not open, even with the key. I think I can get to the locking mechanism by removing some panels, but it is just another frustration.
In the mean time, I'll probably order a new carb. Original Chinese one is on there now, not sure how reliable they are. Opinions w/ just getting a new one? Is that the right thing to do?
Thanks
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Post by jersey on Oct 6, 2013 19:23:08 GMT -5
Ok, little update - I fixed the seat lock problem: seems when I'd had the side body panel off, the cable housing had slipped free of the cable housing retainer, so when I turned the key, instead of it pulling the cable back and releasing the seat latch, the whole housing was moving. I felt around up under there (the under-seat bucket was already out), found the cable housing and held it with my fingers while turning the key so it actually pulled the cable. Latch opened.
Anyway, let me know what you think about the carb - thanks
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Post by skuttadawg on Oct 6, 2013 23:23:29 GMT -5
Check the tubing from the airbox to the carb for leaks as well as the intake maifold . I had a small vacuum hose pop off of my TaoTao and man it ran like crap . I made it home and noticing the little hose dangling . I saw where it was attached but the clip was gone too . I put on a screw down clamp since they hold better and it was good again .
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Post by alleyoop on Oct 6, 2013 23:47:08 GMT -5
If it is a newer scooter 2012+ the carbs come with the fuel ratio mixture screw plugged and some even the carb bowl bolts. And now since the weather is changing to cooler temps motors need more gas. So you have to richen up the Carb so it feeds more fuel. So if the Fuel Ratio Mixuter screw is available and not plugged up richen it up. Turn it Counter Clockwise to get the HIGHEST IDLE out of that screw.
If it is plugged you have 2 choices Drill the plug out to get to the screw behind it or get an aftermarket carb 24mm which is what is on there.
Make sure you have NO VACUUM LEAKS, rips in the air filter tubing, cracked air box, cracked intake manifold, cracked vacuum lines etc..
Alleyoop
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Post by skuttadawg on Oct 6, 2013 23:49:44 GMT -5
Have you checked the diaphragm for tears in the top of the carb ?
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Post by alleyoop on Oct 6, 2013 23:58:13 GMT -5
If it Sputters at all revs it is not his diaphragm, that comes into play around 20+mph.
Alleyoop
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Post by jersey on Dec 28, 2013 17:46:16 GMT -5
Hi all -
update: I removed the carb, took it apart and sprayed everything with carb cleaner per instructions on youtube. I'm no expert, but it seemed in fine working condition. Nothing bent, no crud, no dry rot or tears in the diaphragm. Plenty of fuel came out of the bowl. I did notice what looked like a tiny amount of sandy residue in a couple places inside the carb, which blew away with the carb cleaner. Anyway, I reassembled it and ... still the same problem. It will sputter but stay running if I give it throttle and bring it to 2.5 - 3K rpm. As soon as I release the throttle, it dies.
Incidentally, the air / fuel screw is indeed available for adjustment. I could try to richen the mixture and see what happens.
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Post by skuttadawg on Dec 28, 2013 21:44:34 GMT -5
Drain out the gas in the tank . My 2T when it was new ran like a champ . Well one night I bought some gas from a shady place and the next morning it would not start up . It always starts up instantly . I first checked the sparkplug wire and then for fire since I knew I had a full tank of gas as well as good compression . I called my dealer before going too far as it was under warranty . They told me about a scooter with the same no start issue after it had been running good . He said they drained the tank and carb bowl and it had water in the gas . Refilled with ethanol free gas and tada it was good again . I bought a siphon pump from Harbor Freight and did the same thing to mine . I was thrilled it started right up like the other scoot did . I try to only get gas from trusted sources but sometimes I have no choice sine the tank is so small I fill it up for 2.50 of premium . I have had it happen two more times but I only drained the carb bowl and it fired right up .
So I would try draining out the gas and refilling with good gas and see what happens .
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Post by keikara on Mar 19, 2014 15:13:56 GMT -5
I know this is an old thread but I had the same problem with a 2013 150cc Jon-way scooter with 300 miles on it. Did everything that was stated here and on other sites finally took it to the dealer, turns out there is a sensor on the camshaft that can go bad, dealer is fixing at no charge. Dealer also stated that the cheaper Chinese version still use the sensor but that the Taiwanese versions do not use this sensor due to the problems with it.
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..BAD TO THE BONE..
