I bought an off brand Chinese 150cc scooter used. i have adjusted the valves to a setting that seems to work best during the colder days. I have also cleaned the Carb and replaced the electric choke. It ran great for a while with the exception of backfiring. I now have a new problem; if I drive it for more than a few miles at a time it will act like it is choking, then it loses power and when I come to a stop it will die. If I sit for a bit and try to crank it a few times it will eventually restart and then run like nothing has happened.
I suspect you have a faulty petcock or on some models perhaps a fuel pump. Check the vacuum hose for leaks to these. It usually runs off the intake elbow, that the carb is attached to. If there is a plastic 'T' in the vacuum line replace it with brass...
What is happening is the float bowl fills with gas and you run for a few minutes. Then it empties and it stalls out. When it is running there is probably not enough vacuum to keep the float bowl filled...
I would check the valves...this could also cause a drop in vacuum pressure...
If you have a fuel pump you may also have adjusted the valves too far out so it is not getting a good enough pulse to pump enough gas to keep it going at speed. Also an ignition pickup going bad can give you a similar problem.
Did you adjust your valves Intake .004 and Exhaust to .005? You mentioned that " i have adjusted the valves to a setting that seems to work best during the colder days" what did you adjust them to? If adjusted right it does not matter whether its cold or hot, that is more to do with the amount of fuel it requires. Cold Weather requires more fuel to be feed so you richen it up, Hot Weather you may have to Lean the Carb out. Lefty
Thanks for the advice. I am going to check the valves again this weekend as well as the fuel filter. Seems like I am always having to adjust those things. I read up on the ignition pickup, sounds similar to what I am dealing with as well. It doesn't nor has it ever liked to idle.
It has been a while since posting on this so. I adjusted the valves to spec and it started, idled and ran great. However, it still died after driving a little while. With time the distance I drove before it died got shorter and shorter. Now it is less than 2 miles. I checked the fuel filter and made sure that the fuel pump was getting enough vacuum to move the gas. Gas runs great into the fuel filter and the filter is not clogged. It started, but idled rough. After helping it idle to give the fuel system a chance to regain the fuel lost due to changing fuel filter, the engine was bogged down and shut off when giving gas. Now I can not get it to start at all.
Backfiring is caused by a LEAN condition. So start checking for air leaks, Header Pipe is always suspect when backfiring, Vacumm hoses cracked Intake Cracked Air Filter cracked etc.. You have a leak somewhere, if it has emssion stuff check those hoses and where they connect as well. It should only be getting air from the Air Filter. Lefty
Longbo 150cc Prodigy and the Voyager. Buy them as cheap as you can, find the cheapest parts . Ride em hard . They will break anyway .
Post by danwhittaker on Apr 9, 2011 20:28:04 GMT -5
i had the exact same issue about a month ago.. tried everything i could possibly think of before ordering new parts.. nothing seemed to help..
i replaced my cdi box and my ignition coil with performance parts..
since then ive put nearly 500 miles on it without a single issue..
i was told by numerous people on here that neither part sounded faulty, due to the symptoms. (backfiring, bogging down and dying, hard to restart..) might be something to look into. symptoms are identical to the issue i was having.. it was only a $50 fix.
The CDIs have capacitors in them and while they will work, they get slow to charge and this sets the engine into a 'retard' spark state.. it usually runs very poorly at 1/2 throttle and above...
The coils can also become slow to charge and this causes the engine to run like the timing is out of whack, which it is...hence the backfiring.
The problem is that these conditions are very hard to diagnose and they can be intermittent, based on things like heat etc.
I recommend everyone change their CDI, ignition coil and pick-up coil (Hall Effect stator trigger) every 3rd season, even if the scooter is running fine. Costs about $50.00 for stock parts and $80 for NCY or better parts.
wereed: HOw can I start a thread?
Jun 1, 2013 10:55:49 GMT -5
wereed: or respond to a thread I started three years ago...
Jun 1, 2013 10:56:07 GMT -5
marklorenzi: I just bought one of the Fleetwoods. They look like a clone of the Honda XRM's they sell overseas. It is in transit now and I should get it this week. I will try to post my experience here. Call me the guinea pig hahaha.
Jun 2, 2013 20:29:11 GMT -5
flyangler: wereed, this forum is read only the new forum is on the banner above. Dan
Jun 5, 2013 7:35:29 GMT -5
silkyg1973: can someone please tell me how to post
Jun 10, 2013 12:08:46 GMT -5