dbx 2 stroke scooter wont start and spits gas out exhaust

kickerfanatic · 02-20-2012, 11:05 AM

i have a 43cc or 49cc dbx gas 2 stroke scooter.

i picked it p from craigslist for $25. the seller said it was not used and just sits there. so i figured hey its only $25.

poblem is when i tried to prime it using the primer bulb it would not suck any gas at all.

i then inspected gas lines from carb to inside gas tank, found a rip in the sending line and replaced it.

i put carb back on and tried priming it again. suprisingly it did prime but it would not start.

so i pull started it some more to try to start it and every time i yank on the pull starter i get a nice stream of gas spitting out of the exhaust end of the motor. the carb has no air filter on at the moment but gas is only going one way. out the exhaust and all over the floor. i mean a nice lil stream of gas.

any ideas what could cause this ? i never seen anything like this before and can find no answers on the net...

Weldangrind · 02-20-2012, 09:36 PM

You're running really rich with no air filter. Figure out how to cobble some sort of air filter, change the plug, clean the carb and try again.

kickerfanatic · 02-21-2012, 12:52 PM

so if i put an air filter on, it should stop spitting raw gas out the exhaust ?

i already put a new plug and cleaned the carb..

thanks.

FastDoc · 02-21-2012, 01:27 PM

You may have a pumper carb which I am not familiar with but I bet this article will help.

http://www.dansmc.com/pumper_carb.htm

Weldangrind · 02-21-2012, 08:18 PM

It can't hurt. Fuel and air need to be mixed within a certain range, and you're well outside of that range with no filter. I wouldn't expect the fuel to ignite.

waynev · 02-21-2012, 08:48 PM

I'd have to say that it would be leaner without an air filter as any air filter will restrict the air flow a bit, to me if it's spitting fuel out of the exhaust then the crankcase is getting full of fuel, be careful and make sure you don't hydrolock it, that's a good way to do damage.
If the tank is mounted above the engine then the odds are the fuel is siphoning into the engine and causing it to fill up with fuel, could be a dirty or bad needle and seat.
Another bad example i have seen of this was on a snowmobile, the guy hooked up the impulse and fuel lines on his fuel pump backwards, so everytime he pulled the starter rope he was filling the crankcase with fuel, it got to the point of hydrolock and broke his starter.

MICRider · 02-21-2012, 09:56 PM

Quote:

Originally Posted by waynev

I'd have to say that it would be leaner without an air filter as any air filter will restrict the air flow a bit, to me if it's spitting fuel out of the exhaust then the crankcase is getting full of fuel, be careful and make sure you don't hydrolock it, that's a good way to do damage.
If the tank is mounted above the engine then the odds are the fuel is siphoning into the engine and causing it to fill up with fuel, could be a dirty or bad needle and seat.
Another bad example i have seen of this was on a snowmobile, the guy hooked up the impulse and fuel lines on his fuel pump backwards, so everytime he pulled the starter rope he was filling the crankcase with fuel, it got to the point of hydrolock and broke his starter.

This makes sense, I also recall reading that the carbs on these little two stroke scooter engines were prone to leaking. I recall a youtube video where the scooter owner picks up the back of the bike and drops it 6 inches or so to jar the carb to get it to seal.

Weldangrind · 02-21-2012, 11:39 PM

waynev, you're exactly right (again). Thanks for setting me straight.

02-20-2012, 11:05 AM	#1
kickerfanatic Join Date: Jan 2012 Posts: 16	dbx 2 stroke scooter wont start and spits gas out exhaust i have a 43cc or 49cc dbx gas 2 stroke scooter. i picked it p from craigslist for $25. the seller said it was not used and just sits there. so i figured hey its only $25. poblem is when i tried to prime it using the primer bulb it would not suck any gas at all. i then inspected gas lines from carb to inside gas tank, found a rip in the sending line and replaced it. i put carb back on and tried priming it again. suprisingly it did prime but it would not start. so i pull started it some more to try to start it and every time i yank on the pull starter i get a nice stream of gas spitting out of the exhaust end of the motor. the carb has no air filter on at the moment but gas is only going one way. out the exhaust and all over the floor. i mean a nice lil stream of gas. any ideas what could cause this ? i never seen anything like this before and can find no answers on the net...
	0

02-20-2012, 09:36 PM	#2
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	You're running really rich with no air filter. Figure out how to cobble some sort of air filter, change the plug, clean the carb and try again. __________________ 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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02-21-2012, 01:27 PM	#4
FastDoc Join Date: Mar 2009 Location: Southeastern Washington desert Posts: 14,761	You may have a pumper carb which I am not familiar with but I bet this article will help. http://www.dansmc.com/pumper_carb.htm __________________ Happy to serve.
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02-21-2012, 08:18 PM	#5
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	It can't hurt. Fuel and air need to be mixed within a certain range, and you're well outside of that range with no filter. I wouldn't expect the fuel to ignite. __________________ 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
	0

02-21-2012, 11:39 PM	#8
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	waynev, you're exactly right (again). Thanks for setting me straight. __________________ 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
	0

02-21-2012, 12:52 PM	#3
kickerfanatic Join Date: Jan 2012 Posts: 16	so if i put an air filter on, it should stop spitting raw gas out the exhaust ? i already put a new plug and cleaned the carb.. thanks.
	0

02-21-2012, 08:48 PM	#6
waynev Join Date: Aug 2009 Location: London, Ontario Posts: 1,097	I'd have to say that it would be leaner without an air filter as any air filter will restrict the air flow a bit, to me if it's spitting fuel out of the exhaust then the crankcase is getting full of fuel, be careful and make sure you don't hydrolock it, that's a good way to do damage. If the tank is mounted above the engine then the odds are the fuel is siphoning into the engine and causing it to fill up with fuel, could be a dirty or bad needle and seat. Another bad example i have seen of this was on a snowmobile, the guy hooked up the impulse and fuel lines on his fuel pump backwards, so everytime he pulled the starter rope he was filling the crankcase with fuel, it got to the point of hydrolock and broke his starter.
	0