Carb Trouble

H

HardcoreHadaway

New Member
I am having trouble with fuel, and so I think it is the carb. When I turn the petcock off it goes like spit....until the fuel runs out. Then When I turn it back out I bog down to maybe 10 km.
 
It would help if we knew what engine and carburetor you have.

When asking for help or advice please give us some information to work with. Is your engine a 2 stroke or a 4? What carburetor does your engine have? What have you tried to remedy the problem? What have you checked?

See what I mean?

Tom
 
I am running a very standard kit. Black 80 slant 2 stroke. 66cc. The carburetor in question is the stock china piece of **** that causes everyone problems on this forum.

My problem is defiantly the float, which i adjusted by bending the metal prongs down toward the bowl to ensure the seal... I don't think it's sealing right. When I have the fuel on I think it's flooding When I turn the fuel off from the tank it goes so fast I broke the mounts.

So I will have a few days to wait for the 20 dollar speed carb. to arrive while I fix the mounts.

Marble cheese gets the best from both worlds.

Thanks for the help guys.
 
HardcoreHadaway said:
I am running a very standard kit. Black 80 slant 2 stroke. 66cc. The carburetor in question is the stock china piece of **** that causes everyone problems on this forum.

My problem is defiantly the float, which i adjusted by bending the metal prongs down toward the bowl to ensure the seal... I don't think it's sealing right. When I have the fuel on I think it's flooding When I turn the fuel off from the tank it goes so fast I broke the mounts.

So I will have a few days to wait for the 20 dollar speed carb. to arrive while I fix the mounts.

Marble cheese gets the best from both worlds.

Thanks for the help guys.
Click to expand...

Just wanted to add something here, I'll bet there is nothing wrong with your current carb...

If you bent the tab down that rides against the fuel inlet and shut off needle you went the wrong way with it, if you bend the tab up toward the needle holding the carb as it would be if mounted on the engine this will lower the float level and keep the needle for staying open to long thus causing the fuel level in the bowl to be to high.

If you will take the Throttle slide out of the carb ( the barrel shaped thing that the carb cable is attached to) and remove the cable so that you can remove the metering needle you can likely raise the small clip that is on that needle to the second highest position and this will lean the low to mid-range fuel mix, this will help with the problem your having most likely, however until the main jet size in the carb is reduced it will probably never run as good as it can and should, almost without acception these engines run way rich on fuel because the carbs are jetted to big, I solder mine up and re-drill the main jet with a #72 or #73 wire gauge drill bit and then adjust the metering needle to the best setting for a good low to mid range mix, these simple mods will have the NT carb purring on these engines, the NT carbs are so simple there really isn't much to go wrong with them that some easy adjustment wont usually fix....

When you get the Speed Carb you'll have to do these same things to it if you wont it to perform like it should on your engine, I dont have any of the speed carbs but the only advantage I can see to them over the standard NT carb is the fuel shut off, looks to me that the rest is just the same, I have heard that the throat of the carb is maybe 1mm larger or something like that.

My oldest build from back in 2009 has the NT carb, I reduced the size of the jet in and moved the needle clip up one notch on and stuck it back on the original Aluminum intake, carb has not been touched since then, now 2000 miles later and not a single issue, very simple carbs and very easy to tune on these engines.

Hope some of this will help you out here, sorry I don't have a video or a pile of picks to show things more clearly, at end of this message I'll include a link to where you can get a set of the wire gauge bits for really cheap and you will only need a small propane torch and a can of carb cleaner so you can solder the hole up and re-drill the jet for your carbs, I just hold the jet with pliers with the jets threads pointing up, I spray jet off well with carb cleaner to remove any oil, let it dry for a couple minutes then with some small solid core solder laying close by and ready, I start heating the jet up with the torch which only takes about 15-20 seconds, turn off and set the torch down and while it is good and hot stick the solder down in the hole so a SMALL..... amount of it melts into the jets metering hole and fills it in, now just sit the jet aside for a couple minutes to cool, go ahead and get the #72 wire gauge bit chucked up in the little pin vise drill chuck, now drill the jet slowly gently from the opposite end than you put the solder into turning the drill slowly and keeping it as straight as possible so you don't wollar out the hole and make it bigger than the size you're drilling out to, once you get this done put the jet back in the carb, clean the spark plug off good with wire brush and carb cleaner, take the bike out on a short ride like maybe 1/2 mile one way and then back home, let the engine cool for 10 minutes and then pull the spark plug and see what the color is, if its a nice light to medium chocolate brown and the engine doesn't 4 stroke (sputter....blap blap blap.....) under a load or at the comfortable cruise speed, you have it tuned in pretty good, if the plug color is white or very like gray when you check it just pull the carb bowl, remove the jet and drill it out with the next size larger bit, which would be #71 if the original size you used was the #72, if it 4 strokes..blap blap blap.... and the plug color is a bit dark, just heat the jet with the torch until the solder that is already in it melts and reseals the hole, then re-drill with the next size smaller, would be the #73 which is where all my NT carbs run the best.

If you don't have a torch you can pick up a small propane torch at most any hardware store or Home Depot and Lowes, you could also set the jet on the burner on an electric stove and check it after about a minute to see if the solder will melt in it, as soon as the solder will melt and fill the hole you will have it done that way and not have to buy a torch if that would be a problem and you don't have one.

Heres the links for the bit & pin vise you'll need for the job, best wishes.

http://www.widgetsupply.com/product/WB05.html (Drill Bits)

http://www.widgetsupply.com/product/BCX15.html (Pin Vise)

Peace, Map
reddd
 
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You're the bomb Mapbike! I have the throttle set like you're suggesting. I will try bending it the other way, got nothing to lose. If i have to mess with the jet so be it. I think it's flowing fine though cause when I turn off the gas it uses whats still in the bowl just fine, when I turn the gas back on it floods.
 
One other note, what angle is your carb at?
It needs to be as level as possible as it is completely gravity based.

And your motor mounts broke from over-reeving as the fuel mix leaned out as fuel ran out?
You have far more important issues to look at than the carb if your motor mounts are that poor as few things are more catastrophic than a motor mount breaking at high speed.
 
HardcoreHadaway said:
You're the bomb Mapbike! I have the throttle set like you're suggesting. I will try bending it the other way, got nothing to lose. If i have to mess with the jet so be it. I think it's flowing fine though cause when I turn off the gas it uses whats still in the bowl just fine, when I turn the gas back on it floods.
Click to expand...

You're welcome, I guess I didn't catch what KCvale is talking about concerning a engine mount issue, but if you are having issues with the mounting studs breaking, be sure to resolve that issue by upgrading the studs and making for curtain all of the mounting hardware is in tip top condition, that is very important, road with a fella one time that had his engine mounted up in a very non-secure way, front mount broke loose which in turn caused rear mount to break loose which allowed engine to turn at an angle enough to pull fuel line loose from petcock so at about 25mph engine started flopping in frame and fuel spilling all down on top of the hot engine and spark plug boot while he was still going...... that could have got very very ugly and resulted in him going to a B-BQ as the main dish..........ouch!

Also be sure that the float needle slides freely inside the the seat, if it has a bur on it that causes it to hang in the seat no matter how you adjust the float it will continue to cause the flooding problem, but hopefully a simple adjustment will remedy the flooding and you can get going again quickly.

Map
reddd
 
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Welcome Charles. Please fill in some blanks for us. Is the reed valve & carb a new performance add on or was it with the motor when you bought it? Is it a 66cc motor (sold as an 80cc). Does the piston have a reed window machined in it's side wall or has the cylinder jug been modified with a third port? If one are both of these mods haven't been made the carb an reed won't make horsepower in fact it could cut your original power in half...not good.

Is the engine running and if so does the plug indicate it's rich or lean? Is it 4 stroking etc.or what type problem are you trying to correct?

Rick C. .
 
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