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Post by rich5857 on Mar 18, 2012 17:33:00 GMT -5
I'm trying to adjust the air/fuel ratio on on my carb because it's running lean. I've come to that conclusion because I have lost power and the spark plug is white. The problem is there is a copper plug over the adjustment screw so I have no idea how to remove the plug or if it's even adjustable. I also was going to take the carb apart to clean it, but the screws holding the two halves of the carb together are plugged as well so it seams I can't even take the carb apart. Any help would be appreciated. Thanks!
Also... How do I plug the gas line if I were to take the carb off to clean?
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Post by timber on Mar 18, 2012 19:42:06 GMT -5
I'm trying to adjust the air/fuel ratio on on my carb because it's running lean. I've come to that conclusion because I have lost power and the spark plug is white. The problem is there is a copper plug over the adjustment screw so I have no idea how to remove the plug or if it's even adjustable. I also was going to take the carb apart to clean it, but the screws holding the two halves of the carb together are plugged as well so it seams I can't even take the carb apart. Any help would be appreciated. Thanks! Also... How do I plug the gas line if I were to take the carb off to clean? You have to drill that little brass plug out with a small drill bit and can use a drywall screw to pull it out to access the mixture screw Mine came right out easy once I drilled a small hole in the center of it. The plug is only about 1/8" thick at most so dont drill too deep. The bowl screws it seems you have to grind a slot with a dremel and cutoff wheel. I'm looking at just getting a better carb, and one that you don't have to mess with drilling and slotting things just to access. |
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Post by phillylightguy on Mar 18, 2012 19:45:53 GMT -5
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Post by rich5857 on Mar 18, 2012 20:17:28 GMT -5
Thanks for the responses. I'll go ahead and try to drill it out.
Is there a good carb you'd recommend in case I decide to get a new one?
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Post by timber on Mar 18, 2012 20:33:35 GMT -5
Thanks for the responses. I'll go ahead and try to drill it out. Is there a good carb you'd recommend in case I decide to get a new one? I'm going to try one from our Maine guy here, probably not much of an "upgrade" but at least you can get into the thing without having to drill out tamper proof screws and things, and it will provide me with a spare as well as a test to see if the swopping carbs runs better. My stock carb didnt seem to really run right from day 1 and I think that's where my problem has been with poor, erratic idling, and it seemed like it might have been flooding as well. It might very well be dirty or a clogged passage inside somewhere, I never messed with it. But with the tamper proof screws I don't want to bother with having to drill that stuff out. Sometimes it's just easier, quicker and better to just replace the stupid thing than messing around with tearing into it and piece-meal replacing little parts on it. Probably true of the clutch and variator parts. These are reasonably priced at $34.99 and ready to put in; eshop.mainelyscooters.com/product/cat-139qmb/139qmb-50cc-4-stroke-carburetor-type-4/Carburetor Type-4 for 50cc 4-stroke QMB139 engines. Comes with charcoal cannister hook-up, accelerator pump and electric choke. *FITS MOST CHINESE SCOOTERS* Inner Diameter (intake): 20mm Outer Diameter (air filter mount): 38mm Electric Choke (plug style): 2-pin, male Accelerator Pump Charcoal Cannister Hook-Up On the gas line, I would probably just drain the tank into a jerry can rather than bending the hose over and crimping it or trying to stick something in it. I do believe tho without the engine vaccuum the gas valve stays off, so you might not even have to do that, the gas that will come out would be in the short line from the carb to that valve, but be ready with a can just in case it leaks somehow. |
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Post by rich5857 on Mar 18, 2012 20:44:40 GMT -5
Awesome, Thanks!
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Post by timber on Mar 18, 2012 21:13:17 GMT -5
You are welcome! I'm sure there's loads better carbs out there if you want to spend the big money, but I think most of the higher priced carbs are for racing and high performance, or they are chrome plated, and we don't need that kind of stuff for a 49 cc scooter  But I'll see how this carb works and post the results good or bad. |
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Post by rich5857 on Mar 18, 2012 21:21:49 GMT -5
Sounds good, I'd be interested to hear the results. I'm going to try to drill out the plug and adjust the A/F adjustment screw first and see how it runs before I buy a new carb.
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Post by skuttadawg on Mar 18, 2012 21:44:28 GMT -5
You can get larger jets or a better carb for 50 or less which is better than replacing a burned up piston from running too lean
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Post by redbullf1 on Oct 14, 2012 14:10:47 GMT -5
I cant afford a new carb im poor. but there is a very easy way to unrestrict the carb and all you need is a drill and a hacksaw as well as 15 min of your time its easy if you have mechanical ability. Use a hacksaw to cut a line right down the middle of the screw that needs removal but Only cut deep enough to use a screw driver to get that bolt out. Its kinda hard to explain it but im working on a video to put up on you tube. Now mind you that when tax season comes i will be spending some money on a bbk new bigger carb air filter performance exhaust and most of the transmission components as well (around 700 dollars worth) for now this will do since i have to store my scooter soon..reno nv is not scooter friendly during winter. happy scooting
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Post by prodigit on Oct 14, 2012 16:44:16 GMT -5
Subscribed!
These may be things I need to look at soon as well!
Would it work just to replace the carburetor, without any other modifications?
If so, will I experience a performance boost?
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Post by mainepeace on Oct 14, 2012 17:31:30 GMT -5
Not all carbs have an A/F screw under the cap. 2011/2012 carbs do not, and many 2010 don't either.
No, you won't get a performance boost just by replacing the carburetor, unless the carburetor is a restriction or not working properly. The stock carb is 18/19mm and a larger carb will not give you more power on an otherwise stock 50. If your current carb isn't working properly or is jetted improperly then a new carb will help.
Greg
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Post by prodigit on Oct 14, 2012 20:31:34 GMT -5
I don't know if it's working properly. Just trying to figure out where the spark plug is, and if I can remove it without removing the whole tupperware armor, so I can have a look.
After how many miles can I see if the engine runs too lean? (meaning, after how long driving will the spark plug turn white?).
I was just expecting, if the jets are larger on the new carb, and the mixture runs richer (more perfect), performance should increase!
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Post by redbullf1 on Oct 16, 2012 23:16:28 GMT -5
I finally got to test my stock carb with a bigger main jet.. the thing is if your engine cant get the proper amount of fuel it will never make its full stock power. also my stock carb had a 79 main jet and i had problems like for example if i gave my scooter too much throttle too fast it would bog down and actually lose power and kinda feel like it was going to stall even after i unplugged my A/F screw and adjusted my carb. well with the current 81 jet i have in there now it no longer does that and believe it or not i have faster take off and 5 mile an hour higher top speed. (please note that what worked for me will not work for everyone) I live in a very high altitude in reno nv with my scooter bone stock i was maybe hitting 28 or 29 miles an hour but usually i cruised around 25 the very experience scooter mechanic at my local scooter shop told me to put lighter roller weights (went from 5 gram to 4.5) and a slightly bigger main jet and well as soon as the carb was tuned properly my scooter will accelerate up to 35 mph in what i consider a normal fashion no more bogging down and my scooter is now a happy peppy scooter a lot more fun to ride now. these were very cheap mods i got a set of rollers brand new for free since i traded my scooter trunk for them ( trunks make scooters look ugly lol) and the jet well those things are literally dirt cheap. but please remember these mods worked for me mainly for 2 simple reasons I am 260 pounds and i live above 5000 feet. talk to scooter riders in your area and see what worked for them especially if they are about your weight good luck happy scooting
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Post by carasdad on Oct 17, 2012 8:07:12 GMT -5
I don't know if it's working properly. Just trying to figure out where the spark plug is, and if I can remove it without removing the whole tupperware armor, so I can have a look. After how many miles can I see if the engine runs too lean? (meaning, after how long driving will the spark plug turn white?). I was just expecting, if the jets are larger on the new carb, and the mixture runs richer (more perfect), performance should increase! To remove the plug...pull the plug cap..use a standard deep well plug socket( the small one in your tool kit) No need to remove the engine cover cooling housing plastics. The plug is there..it's just deep...once the cap is pulled..poke a finger in the hole.....you will feel the plug. Being one of the new TaoTao scoots that they jet way lean...expect to find your plug near white or a slight ashen grey.  If so..slot the shear screws on bottom of carb with a small hacksaw or use a dremel tool cutoff wheel. Remove the screws with a standard flathead screwdriver. Take the old screws to your hardware store and get new ones to replace those..  |
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Post by redbullf1 on Oct 17, 2012 21:04:25 GMT -5
I will be adding my video to youtube sometime tomorrow morning on how exactly to fully de-restrict stock carbs like i said on my post above its easy. hope you guys check it out before you spend 50 bucks on a new carb. Im waiting to buy a new carb when i get a BBK next february for now this will do.Link will be posted as soon as video is visible on youtube. thanks and happy scooting
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Post by prodigit on Oct 17, 2012 22:06:37 GMT -5
I'm trying to improve my tao atm50, but when it goes between 35, 37 and 40MPH, I think I probably get as much performance out of it as possible... Still I'd love to see if I can remove the brass cap, and improve performance a bit more.
Today I was working on a grass trimmer. It turned out it was running a too rich mixture.
By lowering the choke (adjustment screw idle), seemingly the top end performed better.
Perhaps if my scoot is running too lean, adjusting to a richer idle, may improve performance in the top end, without much other modifications?
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If so..slot the shear screws on bottom of carb with a small hacksaw or use a dremel tool cutoff wheel. Remove the screws with a standard flathead screwdriver. Take the old screws to your hardware store and get new ones to replace those.. 