Hesitation With Throttle.. « Thread Started on Sept 10, 2011, 11:12pm »
I have had my scooter for around 3 years now and have a love/hate relationship with it. I am constantly having problems with it running correctly. It is always something new and different.
With the most recent set of events. The scooter was running crappy so I pulled the carburetor and cleaned it out as well as the main and low jets. Upon reinstall, I am now getting a problem where when it finally gets started after filling up with gas, if you give it any throttle, it wants to die and it will hesitate. I am thinking the fuel filter may be clogged or giving me trouble.
I have re-cleaned the carb several times as well as just did a valve adjustment and replaced the spark plug. I ordered a new carburetor online to hopefully fix my problems but I want this running and trying to figure out what is going on before the new carb comes in.
Joined: Oct 2008 Gender: Male Posts: 3,163 Location: Yuma, AZ
Re: Hesitation With Throttle.. « Reply #1 on Sept 10, 2011, 11:46pm »
it's either too little amount of gas goes to the combustion chamber OR to much gas ,that the sparkplug cannot burn..is the petcock working ok? see if there is pressure leak too. or may need to adjust air /fuel screw properly.
Re: Hesitation With Throttle.. « Reply #2 on Sept 11, 2011, 8:32pm »
randomly changing carburetors is a costly and non accurate idea for a repair. "running crappy", what do you mean? starting? WOT? Have you pulled the plug after running it to see how it is burning?
Joined: Jul 2011 Gender: Male Posts: 1,564 Location: Colorado
Re: Hesitation With Throttle.. « Reply #3 on Sept 12, 2011, 10:26am »
When I had the same symptoms, I had the smallest tear in the diaphram on top of the carb. Hopefully your new carb will solve your problem as well as it did on my scooter. After setting your valves and cleaning the carb, you were correct to order a new carb. Its pointless to rebuild the carb since a new one is like $10 more than the rebuild kit.
Joined: May 2010 Gender: Male Posts: 570 Location: Indianapolis, IN
Re: Hesitation With Throttle.. « Reply #4 on Sept 12, 2011, 2:36pm »
If a thorough PDI has never been performed on this scooter, you will continue to have similar results. Good news is, it's never too late to get in there and do this vital task. Much of it can be done while the dawgs are scratching their butts coming up with something for you
A/F of some sort does seem to be the gremlin, but the cause could be anything from OEM rubber failure, clogged filter, dirty tank. or even just bad old gas, and sitting too long. (The last possibly the biggest factor atm) or any of the above.
Roketa MC10K50~JMStar 139QMB Scoot Dawg PDI NGK Iridium Plug Fram Fuel Filter Fuel\Vacuum Line Mods~Blue's Way Red Perf Coil Blue Perf CDI 6.5gr Dr Pulley Sliders Gates Powerlink Belt 18mm Carb/Accel Pump Perf Disc Air Filter Mod'd OEM Exhaust
When I had the same symptoms, I had the smallest tear in the diaphram on top of the carb. Hopefully your new carb will solve your problem as well as it did on my scooter. After setting your valves and cleaning the carb, you were correct to order a new carb. Its pointless to rebuild the carb since a new one is like $10 more than the rebuild kit.
I installed my new carburetor tonight that came with a new intake and air and fuel filter and it runs like brand new again. Best $45 that I have ever spent on this damn thing!
When I had the same symptoms, I had the smallest tear in the diaphram on top of the carb. Hopefully your new carb will solve your problem as well as it did on my scooter. After setting your valves and cleaning the carb, you were correct to order a new carb. Its pointless to rebuild the carb since a new one is like $10 more than the rebuild kit.
I installed my new carburetor tonight that came with a new intake and air and fuel filter and it runs like brand new again. Best $45 that I have ever spent on this damn thing!
I spoke a little too soon. With 2 holes drilled in the stock muffler and the free flow filter that came with the new carb, I was getting a lot of popping and hesitation after the scooter heated up. Nothing initially, just after 5 minutes of riding. I played with the air/fuel screw but no luck. I plugged the muffler holes up and still no luck. I then swapped that smaller free flow filter for my old UNI filter and still no luck. I am now back to square one with the stock muffler with the closed up drilled holes and stock intake and it drives great but I am still getting a tad hesitation after it warms up. Do I need to keep playing with the air/fuel screw to dial it in properly?
Re: Hesitation With Throttle.. « Reply #8 on Sept 15, 2011, 12:45am »
Maybe one other thing to check is make sure you get rid of the pair system. This injects a lot of air into the exhaust which can cause any unburned hydrocarbons to pop. This sound is usually muffled to just a pfft but with an open exhaust you just notice it more. Also check the pilot jet size, you really don't need more than a 34 pilot jet size even with exhaust and intake mods. Too much fuel can cause popping on deceleration. And a hesitation on acceleration.
As for tuning, return everything to stock first, then try to figure out what's causing your probelm and then you can go about changing things up. Otherwise you'll never figure out the problem. Also make sure you've got a full jet kit and adjustable needle, it'll help a lot. It's likely with an opened up exhaust AND free filter you may need an even larger jet than what came with your new carb.
Re: Hesitation With Throttle.. « Reply #9 on Sept 16, 2011, 9:03am »
What is the pair system?
I am not getting popping on deceleration, only on acceleration.
I removed my carb last night to inspect the main jet on the new carb and found out it was an #82. I was getting popping with the #82 and the free flow intake as well as with the stock air box.
I swapped out my spare #90 main jet and played around with the air/fuel screw about 15 times going 1/8th of a turn each time in both directions and no luck. I put the new air filter back on to see if that would help the new larger main jet but the popping is still happening. I can not find a point where it is not as bad or stops, it's constant.
Joined: Jul 2011 Gender: Male Posts: 1,564 Location: Colorado
Re: Hesitation With Throttle.. « Reply #10 on Sept 16, 2011, 3:23pm »
You may want to take your intake manifold off and check for a hairline crack at the base. Also look at the spacer under the manifold. They have simple O-rings than can crack. Do you have stock exhaust? Also check that the exhaust pipe bolts are tight.
I am not getting popping on deceleration, only on acceleration.
I removed my carb last night to inspect the main jet on the new carb and found out it was an #82. I was getting popping with the #82 and the free flow intake as well as with the stock air box.
I swapped out my spare #90 main jet and played around with the air/fuel screw about 15 times going 1/8th of a turn each time in both directions and no luck. I put the new air filter back on to see if that would help the new larger main jet but the popping is still happening. I can not find a point where it is not as bad or stops, it's constant.
Tuning this damn thing is stressing me out!
Any ideas now?
If it is POPPING it is to RICH PERIOD. Your Main Jet is TO BIG that is your problem. So put the Air Filter system you want to go with and leave it on and go down on your Main Jet. Usually two sizes down will be enough. So if it was POPPING with the #82 get an #80.
You can try the #82 and try Lowering the Needle and see if that is enough. Now if it POPs at WOT then you will need to get the #80 and put the Needle setting back. Lefty
Re: Hesitation With Throttle.. « Reply #12 on Sept 16, 2011, 7:34pm »
So I swapped in the #85 jet, down from the #90 and I was still getting popping.
I had a brand new spare NGK plug and swapped that out and it run the best it ever has. My speedo was showing 40 mph but that cant be right. I noticed maybe 2 pops but that may be able to be fixed when I play with the air/fuel.
My plug that I pulled out did not look too bad, just had a brown spot on top. Thoughts?
ANYONE SEE SCARFACE TELL HIM LEFTY IS BACK IN TOWN
Joined: Dec 2010 Gender: Male Posts: 5,411
Re: Hesitation With Throttle.. « Reply #13 on Sept 16, 2011, 7:55pm »
Htownscoot, In the previous post you said you had a number 82 and 90 now you say an #85(which is it)?. In EITHER CASE IF IT POPS it is running RICH (PERIOD). I do not understand why you are still asking the same question. If you got an 85 in there now go with an 82 if you have an 82 go with an 80 very simple solution for the popping and running rich. Lefty
Htownscoot, In the previous post you said you had a number 82 and 90 now you say an #85(which is it)?. In EITHER CASE IF IT POPS it is running RICH (PERIOD). I do not understand why you are still asking the same question. If you got an 85 in there now go with an 82 if you have an 82 go with an 80 very simple solution for the popping and running rich. Lefty
I have 2 untagged jets, one #82, one number #85 and one #90.
I am currently using the #85, since I had problems with the #82 and #90. Replacing the spark plug helped a lot but I am not sure why.
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