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Post by phatboy on Apr 30, 2014 21:53:01 GMT -5
Hey
I see others have similar problems, not sure if mine is the same
I just bought a 150cc Chinese scoot, 72 km on it so far. Warm day today (80F) so did some riding
I got to this long steep uphill, a couple miles long. 40 mph speed limit so kept her near WOT most of it, halfway up the scoot lost power so I turned off the road and it dies. After 5 min she started up again. At first it would just idle, if I twisted the throttle it would try to die. Then in a few seconds it would rev again and I took off.
Cruised up the hill again and near the top same thing. 5 min later got it going, rode 20 km or so no issues, normal riding.
Then another long uphill, not WOT. Near the top it lost power again so I immediately stopped and it did not die, just idled and like before it would bog and not rev up. I let it idle for a few seconds and it ran normally again, then rode home.
So yesterday I did overfill the tank, but I did try opening the tank during one of the stalls did not seem like there was vacuum in there. If over filling caused my probems how do I fix it, the tank is no longer over filled after riding 30 km today.
I see adjust valves but would valves cause this. it feels like fuel starving
have other unrelated problems will make another thread.
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Post by JerryScript on Apr 30, 2014 23:16:31 GMT -5
You may be having an issue with lack of vacuum at WOT. The carb looses vacuum pressure at WOT, and sometimes there's not enough vacuum to keep the petcock open, which lets your float bowl run dry and you die. One solution is to install a manual fuel valve, but you must not forget to shut it off when you turn off the scooter or you could have your fuel all leak out.
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Post by alleyoop on Apr 30, 2014 23:34:14 GMT -5
Let me ask a question is your tank lower than your carb or higher than your carb like behind the seat. Reason I ask is if its behind the seat higher than your carb you have a gravity fed fuel system. So going up a hill especially a long one your at an angle and it may be that due to the angle it is not filling up the carb bowl fast enough. You can verify that next time it starts to act up going up the hill Stop or make a u turn and go down the hill and if it doesn't act up, then that is the problem. If so then I would get a Vacuum Pump and not a Petcock.
Alleyoop
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Post by phatboy on Apr 30, 2014 23:55:47 GMT -5
thanks for replies
tank is lower than the carb its under your feet when riding. so it must have some kind of pump?
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Post by alleyoop on May 1, 2014 0:11:14 GMT -5
Cool, then it has a fuel pump, then I would suspect your valves. Adjust them both to .004 inchs. And yes that would cause the same problem, going up a hill puts a lot of load on the motor and gets hotter making things worse. They must be just on the edge where it will shut off even after running on the flats and coming to a stop and it will not want to idle without giving it some gas to keep it running.
Alleyoop
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Post by phatboy on May 1, 2014 2:13:35 GMT -5
did some reading, some one else said you can get gas in the charcoal canister from over filling
just wondering if theres fuel in the cannister, will it ever come out on its own or do i have to drain it out.
Also I found a post that says if valves are tight then vaccum is low, is low vaccum what causes the engine to stall. wonder if i could check that with a vaccum gauge. i have one some where.
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Post by phatboy on May 15, 2014 1:41:22 GMT -5
Hey, the scoot did it again, have more info
this time it did not start (except with starter fluid) not even hours later, meaning its a fuel problem. i thought it was the fuel pump so i looked at the lines, i found that the hose clamp that was suppose to be on the end was on the middle of the line between pump and carb. I didnt think anything of the clamp in the wrong place so i pulled off the line to test the pump, and cranked the scoot, fuel shot out of the pump. i put the line back on correctly and she fired up.
so whats going on here. would the clamp really pinch off the line to the point it would not run at all?
or did running the pump without the hose on it blow out some crap, trapped air or something and make it work again?
Want to get to the bottom of this, so it wont happen again.
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Post by craisin on May 15, 2014 5:56:43 GMT -5
Hey, the scoot did it again, have more info this time it did not start (except with starter fluid) not even hours later, meaning its a fuel problem. i thought it was the fuel pump so i looked at the lines, i found that the hose clamp that was suppose to be on the end was on the middle of the line between pump and carb. I didnt think anything of the clamp in the wrong place so i pulled off the line to test the pump, and cranked the scoot, fuel shot out of the pump. i put the line back on correctly and she fired up. so whats going on here. would the clamp really pinch off the line to the point it would not run at all? or did running the pump without the hose on it blow out some crap, trapped air or something and make it work again?If it runs right from here on you may have got to the bottom of it. Want to get to the bottom of this, so it wont happen again. |
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Post by urbanmadness on May 15, 2014 12:31:02 GMT -5
This is very typical.... Running at WOT, these engines don't make enough vacuum to keep the pump running. An electric fuel pump would solve the problem, or using a different riding technique (see below). Also make sure all the vacuum lines and fuel lines are as short as possible. I have also seen it happen on bikes with vacuum petcocks as well, you lose vacuum, and it closes the petcock.
Bad Valve adjustment, or a worn belt can amplify the problem well. Tire pressures can too. Think about it, these things all affect fuel efficiency.
One way I got around it, is if I knew I was going up a hill, I'd back the throttle off, then go WOT, then back it down and go WOT. that way you keep fuel in the fuel bowl. It's very irritating but it does work. Or the second you feel it bog, back off the throttle for a second or two, then open her back up but not all the way.
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Post by phatboy on May 15, 2014 19:31:50 GMT -5
i hope i solved it, scoot did not do it today. rode it hard today. though it was  yesterday and scoot was idling in traffic for a while and it probably got a lot hotter, today no traffic and 75F on same route. but no problems at all. as for the vaccum problem i wonder if this would work, there are small vacuum reservoirs in the HELP! section of auto parts stores, throw one on with a check valve. seems so obvious, i have to wonder if the scoots already have them? |
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Post by urbanmadness on May 16, 2014 17:12:50 GMT -5
becuase the pump needs pulsed vacume. A vac can, gets rid of the pulse and just makes it a vacumme.
think puff puff puff (what your scooter needs), instead of hisss.
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Post by alleyoop on May 16, 2014 19:29:13 GMT -5
i hope i solved it, scoot did not do it today. rode it hard today. though it was yesterday and scoot was idling in traffic for a while and it probably got a lot hotter, today no traffic and 75F on same route. but no problems at all. as for the vaccum problem i wonder if this would work, there are small vacuum reservoirs in the HELP! section of auto parts stores, throw one on with a check valve. seems so obvious, i have to wonder if the scoots already have them? Nope and not needed. And out of thousands of the guys on the forums with scoots you probably would be the 1st one to try one. Not your cause of a vacuum problem IF you have a vacuum problem which I doubt. Just think of what creates the Vacuum and if all that is good then it is not a Vacuum problem. Alleyoop |
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Post by walterwhite on May 18, 2014 13:21:08 GMT -5
i had an hard start issue since i bought my scoot but i replaced the carb & fuel line and it went away, hope that helps
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Post by phatboy on May 18, 2014 13:42:56 GMT -5
i am thinking of a new carb, i discovred the one on there has no mixture screw and has these brass plugs instead of screws on the float bowl, never seen anything like it.
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Post by JerryScript on May 18, 2014 20:42:04 GMT -5
The air/fuel mixture screw is covered by a brass cap. The "brass plugs" in the float bowl are screws with the heads cut off. Both of these things are done to prevent you from modifying the carb settings so that the scooter can pass certain emissions requirements. You can drill out the brass cap covering the a/f screw, and tap out the cut off screws on the float bowl and replace them. Or you can just replace the carb.
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..BAD TO THE BONE..
yesterday and scoot was idling in traffic for a while and it probably got a lot hotter, today no traffic and 75F on same route. but no problems at all.