49cc Pocket Bike Carburetor Won't Draw Fuel

38396 Views 48 Replies 6 Participants Last post by CAM2, Oct 14, 2012

vaking14

Discussion Starter · Sep 18, 2012

The motor fires up briefly when I manually inject fuel through the throat
of the carb. Will not fire up otherwise. I have completely cleaned the
carb twice. I siphoned the fuel line to make sure that the fuel is available
at the carb fuel inlet. I also have purge pumped the carb (repeatedly pressed the plastic bulb at the bottom of the carb). I have been working
on small engines for four years, but this one has me totally at a loss. Any suggestions?

1 - 20 of 49 Posts

CAM2

· #2 · Sep 18, 2012

Try this..............

Remove the HighSpeedNeedle from the side of the carb...........

Take a can of carb cleaner with a snorkle straw.....stick straw into HSN hole...

Crack the throttle wide open and spray 3-5 3-5 second bursts of carb cleaner into the highSpeedNeedle hole

Take a jewelers screwdriver and richen the LSN 1/4 turn richer

Set the Highspeed Needle to 1 3/4 turns out.............

Make sure the black fuelline is on the larger ribbed nipple and the clear line on the smaller smooth nipple........

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vaking14

Discussion Starter · #3 · Sep 18, 2012

Okay I just did it and it did start for a few seconds but died on me. . . I guess when the fluid burns out it stops running & another problem may be that I dont have an airfilter on the bike all I have is the adapter part on! Do you have anymore suggestions?

vendeta44

· #4 · Sep 18, 2012

Petcock failure perhaps?

http://www.pocketbikeplanet.com/showthread.php?t=39248

vaking14

Discussion Starter · #5 · Sep 18, 2012

This type of two stroke doesnt have one. I have a x7 pocketbike engine; grey & black motor!

vaking14

Discussion Starter · #6 · Sep 22, 2012

The problem i had with this bike was the carb so i brought a new one primed it like 3-5 times, started on the 3rd pull

EPR

· #7 · Sep 23, 2012

Good work, glad you got it fixed.

tycrazyjohn

· #8 · Sep 27, 2012

Hello, glad you got your issue fixed! Not trying to steal this thread, but I have the exact same problem. Long story short I have an old x1 that's been sitting for years. I wanted to get it running so I took the carb apart and cleaned it, replaced the gaskets before and after the manifold, cleaned the fuel lines and tank, changed the spark plug and charged up the battery. It starts just fine, only with starting spray though. I have determined that I'm not getting a single drop of fuel to the carb from the tank. The primer bulb is cracked open (hopefully I can find a new one in town tomorrow) but I didn't think this was necessary to draw fuel, only to help at the start? Also the fuel filter "element" that rests at the end of the hose is missing. Can I buy a new one or do I have to buy a whole new line? I know carbs for these are pretty cheap, and that I'll more than likely have to replace it but I'd like to see if I can get this to work first. Oh and yes, the fuel lines are free of debris and the black one is on the larger nipple and the clear line is on the smaller one. Thanks in advance!

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tycrazyjohn

· #9 · Sep 27, 2012

Just to add to that...I sucked on the fuel line and I now have fuel flowing to the carb with no problem, however it still will only run off starting spray. So basically the carb is not sucking the fuel on it's own. I'm slowly believing that my carb is shot all together, is there a way to make sure though? Should I try cleaning it again?

CAM2

· #10 · Sep 27, 2012

tycrazyjohn said:
Just to add to that...I sucked on the fuel line and I now have fuel flowing to the carb with no problem, however it still will only run off starting spray. So basically the carb is not sucking the fuel on it's own. I'm slowly believing that my carb is shot all together, is there a way to make sure though? Should I try cleaning it again?

Theres a small tiny purgeport in the manifold that needs to pump the inner diaphragm inside the carb to pump fuel

If the hole is clean and clear remove the highspeed needle,,take a can of carb cleaner with a snorkle straw,,stick the straw inside the HSN hole,,rotate the throttle lever to full open and spray 3-5 3-5 second bursts into the HSN hole til fuel sprays out of the Venturi...Once you get the spray replace the HSN to 1 1/2 turns out

Also make sure the fuellines are on right...Black line goes on the larger ribbed carb nipple,,clear line goes on the smaller smooth one...

tycrazyjohn

· #11 · Sep 27, 2012

Alright, just tried that and still the same issue. I sprayed burst until carb spray came out the velocity stack, and replaced the needle and backed it out 1 and 1/2 turns. It started and ran for a second but then died and won't start on it's own again. I took the carb apart again and every port is clean and clear, my only concern is the diaphragm. It "pops" a little but just barely. I've never seen a carb of this type brand new before, so I have no idea if the diaphragm is in normal shape or not. Any more suggestions?

tycrazyjohn

· #12 · Sep 27, 2012

I did notice something I thought was odd, however it may be normal. If I'm not mistaken the purgeport is the tiny hole that runs from the cylinder through the manifold and into the float section of the carb? Well I stuck the straw from the carb can through the manifold and it's clear, and it goes into the cylinder a little ways and stops. Should it keep going? Even more odd is that the purgeport on the carb is blocked off. I don't mean there's gunk stuck in there, it really looks like there was a screw in there that broke off. Is that supposed to be that way?

CAM2

· #13 · Sep 27, 2012

tycrazyjohn said:
I did notice something I thought was odd, however it may be normal. If I'm not mistaken the purgeport is the tiny hole that runs from the cylinder through the manifold and into the float section of the carb? Well I stuck the straw from the carb can through the manifold and it's clear, and it goes into the cylinder a little ways and stops. Should it keep going? Even more odd is that the purgeport on the carb is blocked off. I don't mean there's gunk stuck in there, it really looks like there was a screw in there that broke off. Is that supposed to be that way?

the purgeport is supposed to be open and clear,,,When the straw stops your hitting the 90 degree bend.....That bocked off hole isnt supposed to be that way and your primer bulb should be in perfect working order and not have any cracks or splits in it so its time for a new carb....$13 bux shipped on ebay.............

You can buy a whole new fuelline kit with weighted fuel clunker from home depot..........

tycrazyjohn

· #14 · Sep 27, 2012 (Edited)

The 90 degree bend make sense, I can't see down that hole but now I know why it stops. Yeah I figured a new carb was in order, I'll buy one as soon as I can. I'd still like to tinker with this one for now while I'm waiting, and I think I can buy a new primer bulb from Lowes this afternoon. Do you think I should try to drill out whatever it is that's stuck in the purge port on the carb?

UPDATE:
I went ahead and drilled whatever was in the purge port out. Probably a dumb idea, but I'm ordering a new carb anyways so I figured I'd give a shot. After I got it out I could see a clear passage through the purge hole into the carb body, so I put it together and reinstalled it. As soon as I connected the fuel line, gas started pouring everywhere. It all came from the primer bulb (since it's cracked). Tonight I'll pick up a bulb and try it, but I'm assuming it's not normal for the bulb to fill with fluid as soon as the line is hooked up? If it is then I may have solved my problem. Any input and opinions would be greatly appreciated! I'll post again tonight after I put the new bulb on.

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EPR

· #15 · Sep 27, 2012

There is a knotch in the cases where the 90 degree ends that is open that feeds the cylinder. No clear port no pump gas.

tycrazyjohn

· #16 · Sep 27, 2012

You're talking about inside the cylinder itself? That one I'm pretty sure is clear, and I know the manifold and gaskets are clear, and the carb is now clear since I drilled it out. Should that primer bulb instantly flood with gas or only after you pump it?

CAM2

· #17 · Sep 27, 2012 (Edited)

tycrazyjohn said:
You're talking about inside the cylinder itself? That one I'm pretty sure is clear, and I know the manifold and gaskets are clear, and the carb is now clear since I drilled it out. Should that primer bulb instantly flood with gas or only after you pump it?

only after you pump it up..Thats why its called a primer bulb...it primes the carb with fuel and theres a red or orange check valve that needs to be operating correctly aswell....

tycrazyjohn

· #18 · Sep 27, 2012

CAM2 said:
only after you pump it up..Thats why its called a primer bulb...it primes the carb with fuel and theres a red or orange check valve that needs to be operating correctly aswell....

Ah, that's what I thought. So what would cause it to flood with fuel as soon as the line is connected?

CAM2

· #19 · Sep 27, 2012

tycrazyjohn said:
Ah, that's what I thought. So what would cause it to flood with fuel as soon as the line is connected?

gravity and a siphon effect

tycrazyjohn

· #20 · Sep 27, 2012

CAM2 said:
gravity and a siphon effect

But that would be normal then, right?

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