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Post by jwgarber1725 on Mar 21, 2013 19:53:14 GMT -5
Ok ... So
A while back I bought 2 Roketa MCR-15-50 Scooters
Both 2-Strokes
I finally got to assembling mine and have yet to have it running properly.
I got it to start and run and it seemed ok .. took it 5 miles to a restaurant. Ate something about 35mins.
Came back out and it would not stay running.
Below are the symptoms
1. Hit Starter Button with break lever pulled
--- Motor starts and revs up to either a really high or low RPM depending on where I have the Idle Screw Set.
Then it turns off. It simply will NOT idle and stay running.
This carb has NO Fuel/Air Screw it is a Slide carb with throttle into the TOP
My air filter box has a snorkel coming out to the Carb intake side.
Then right beside that snorkel is another small snorkel that is connected to nothing.
If I cover part of that small snorkel with my finger I can make the bike start up and it will rev to idle point and stay until I pull my finger off. If I pull my finger off the hole it will slowly rev down and then die
So I am thinking since I cut air off and it revs there is a vacuum leak somewhere but I cannot see any obvious leaks or issues.
What I tried
1. Cleaned carb no carb spray just tore it down pulled the jets and ran wire through em. the carb was spotless inside and I mean spotless.
I could see light through the jets and blow air through them freely.
2. Adjusted the idle screw to no end!!
My idle screw also does not have a spring on it.... shouldn't the idle screw have a spring??
My idle screw is awfully long as well. It seems it has to be backed wayy out to keep the slide at a reasonable level.
Trust me it IS an idle screw its not a A/F mixture screw. The spot a AF screw would be is capped off and looking inside the carb itself there is NO screw there.
That is all I have tried. Nothing works.
If I get the bike started by choking the airbox snorkel with my hand then hop on and manage to take off it stays running until I stop and try to let it idle.
So what you guys thinking
Air leak, bad carb issue somewhere, bad gas what!!
Any help would be awesome
Thanks
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Post by alleyoop on Mar 21, 2013 20:03:58 GMT -5
If you have a 2t with a Slider Throttle cable going into the top center of the carb THE CARB HAS an AIR RATIO MIXTURE screw and it is on the RIGHT SIDE near the AIR FILTER INTAKE SIDE. The IDLE SPEED SCREW is in the Center of the CARB to raise or Lower the SLIDE to raise or lower your IDLE. I put together how to tune each type of carb a CVK and or SLIDER carb. Go read this How-To I put together. Alleyoop itistheride.boards.net/index.cgi?board=tt&action=display&thread=53 |
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Post by jwgarber1725 on Mar 21, 2013 21:21:07 GMT -5
If you have a 2t with a Slider Throttle cable going into the top center of the carb THE CARB HAS an AIR RATIO MIXTURE screw and it is on the RIGHT SIDE near the AIR FILTER INTAKE SIDE. The IDLE SPEED SCREW is in the Center of the CARB to raise or Lower the SLIDE to raise or lower your IDLE. I put together how to tune each type of carb a CVK and or SLIDER carb. Go read this How-To I put together. Alleyoop itistheride.boards.net/index.cgi?board=tt&action=display&thread=53I looked inside the carb when it was off the bike. Looking in from the "Intake" side of the carb you can see the channels including the one the A/F mix screw would be used to restrict or allow more air into the channel. Here is a Picture of a similar carb online it is not the one I have but I can demonstrate the screw layout with it.  The white circle is the idle mixture screw. Mine has no spring on it though. the red circle is the A/F mixture screw and channel. However on my carb its a simple small brass washer there with a hole in the middle of the washer. I will take the carb off and inspect it again but I was positive no screw was in there, just the washer. I hope the I am wrong because if there is a screw there it would make adjusting things a of a lot easier ADDED INFORMATION Ohh better picture from your Guide LOL  The silver air ratio screw you show there is where the brass piece with a hole in it is on my carb. That is my exact carb 100% |
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Post by alleyoop on Mar 21, 2013 21:44:04 GMT -5
Then your missing the screw if you look at the carb from the air intake side you can EVEN see the Point of the SCREW in the hole blocking the amount of air coming into that air passage. If it is missing no wonder you cannot get it adjusted. The fuel is constant on these carbs depending on the size of the jets so the adjustment is to either give it more air or less air. If no screw there it will run lean. As far as a Spring on the Idle Speed screw any spring will work maybe a ballpoint pin spring if not just go to the hardware store and get one. You need a little pressure so the screw does not vibrate out. I will not vibrate in because the Slider is pushing down on the screw so it will vibrate out. Alleyoop  |
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Post by jwgarber1725 on Mar 21, 2013 21:57:36 GMT -5
Then your missing the screw if you look at the carb from the air intake side you can EVEN see the Point of the SCREW in the hole blocking the amount of air coming into that air passage. If it is missing no wonder you cannot get it adjusted. The fuel is constant on these carbs depending on the size of the jets so the adjustment is to either give it more air or less air. If no screw there it will run lean. As far as a Spring on the Idle Speed screw any spring will work maybe a ballpoint pin spring if not just go to the hardware store and get one. You need a little pressure so the screw does not vibrate out. I will not vibrate in because the Slider is pushing down on the screw so it will vibrate out. Alleyoop Yea I looked down that channel and there was no screw. The carb on the other bike seems to be exact same way. Just a brass cover is there with a tiny hole in the middle. When I get a chance probably on monday I will take that carb back off and double check to be 100% sure. I will try to track down a spring for the idle screw as well. Id say the ballpoint pin spring would fit fine. any clue why this thing would have just a brass cover and no actual screw? |
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Post by alleyoop on Mar 21, 2013 22:03:32 GMT -5
Yea, they plug them up to run lean for emissions. When you take it off see if you see the point of the screw in there. It may just be a CAP on the screw so customers cannot mess with it. Now on the other hand you may be looking at the screw but no screwdriver slot in which case you can put a slot in it yourself. Or it could be a plug which you would need to Drill out to get at the screw behind the plug like most of the new FUEL RATIO CARBS that come with the scoots now.
Alleyoop
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Post by jwgarber1725 on Mar 21, 2013 22:07:24 GMT -5
This is crazy...
You are most likely 100% correct and I probably just did not see the screw down the channel. I will look closer when I take the carb off again.
Dumbest thing I have ever seen. I hope its a simple cap and not some weird screw with no cuts in it or some bs.
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Post by jwgarber1725 on Mar 27, 2013 22:33:08 GMT -5
Alleyoop...
As usual you were right on the money.
When I took off the carb again to double check everything I went to work on that brass piece covering where the A/F mix screw is.
I finally got it OFF the carb and sure enough there is a A/F screw there.
I drained the entire tank of gas just in case I had water in the gas. Just to be sure it was not the issue.
So I have a empty carb and gas tank
I turned the carb A/F in until snug. Then I backed it out 1 and 1/2 turns.
Put in a bit of gas
and it fired right up and idled.
It did not die until it ran out of what bit of gas I put in it.
I am out of gas so I cannot fill it up with anymore but I think the issue is solved now.
I will let you guys know sometime after I get some fresh gas back into the tank and get working on it again.
Thanks Alleyoop for getting me to check for that A/F screw again. I was told by another person that its possible some 2T carbs would not have an a/f screw so I was sure mine did not.
I was wrong.
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Post by alleyoop on Mar 27, 2013 22:40:46 GMT -5
FANTASTIC!! Glad I was able to help
Alleyoop
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Post by gumby on Sept 12, 2014 0:47:27 GMT -5
Alleyoop... As usual you were right on the money. When I took off the carb again to double check everything I went to work on that brass piece covering where the A/F mix screw is. I finally got it OFF the carb and sure enough there is a A/F screw there. I drained the entire tank of gas just in case I had water in the gas. Just to be sure it was not the issue. So I have a empty carb and gas tank I turned the carb A/F in until snug. Then I backed it out 1 and 1/2 turns. Put in a bit of gas and it fired right up and idled. It did not die until it ran out of what bit of gas I put in it. I am out of gas so I cannot fill it up with anymore but I think the issue is solved now. I will let you guys know sometime after I get some fresh gas back into the tank and get working on it again. Thanks Alleyoop for getting me to check for that A/F screw again. I was told by another person that its possible some 2T carbs would not have an a/f screw so I was sure mine did not. I was wrong. So... How did you get the cap off of the a/f screw? I'm having the same issue. I've had it for 4 days and it hasn't run for more than 5 seconds at a time! It's a "brand new" 2011 2-stroke. I was seriously going to order an adjustable carb, but if I can save $50 and a week of waiting, I might be able to ride this beast before the snow flies here in WI. |
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Post by alleyoop on Sept 12, 2014 22:18:46 GMT -5
Get a 1/16 bit drill bit and drill in the center of the plug just a little not to deep no more than 1/8 of an inch and then get a a small screw with a point a wood screw and screw it in and see if you can either unscrew it or remove the plug.
Now I am saying it may be the actual Air Screw and they just flattened the top of it that is why I say try to unscrew it counter clockwise or it may be a plug and the screw is under the plug.
If Jwgarber172 comes on he will verify which it is or you can try it yourself
Alleyoop
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Post by gumby on Sept 13, 2014 11:52:45 GMT -5
Thanks alleyoop. I'll give it a go this afternoon. I hope I don't have to "notch" it, because I don't have a rotary tool and hate having to buy stuff I won't use much. Here's a pic if it helps anyone...  |
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Post by gumby on Sept 13, 2014 11:54:51 GMT -5
By the way, I'm new here. Fist time scootist and wanted to thank all of you for your help and previous words of wisdom that gave me the confidence to order this machine.  |
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Post by alleyoop on Sept 13, 2014 12:36:07 GMT -5
Great picture to me looks like a plug and to notch it since it looks like brass just anykind of saw blade will work. Or take it to a hardware or garage and they will do it for you I am sure for nothing. Or if you have a file that will work as well does not take much to put a slot IF that is the screw if plug then the screw will be underneath it.
Well since it has a little hole in the center get a small screw one with a point on them and try screwing it in if it is a plug it will start turning. If it turns then pull on it a little or a little back and forth and see if it comes out.
Alleyoop
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Post by gumby on Sept 13, 2014 17:13:30 GMT -5
I got the plug out a lot easier than expected. Just used a small drill bit, and when I pulled it away the plug came with it! Now the bad part. Adjusting the air flow didn't help me at all. I even took the air filter and cover completely off. It would not start at all. I put them back on and adjusted the screw, but I'm back to where I was. It fires up, revs up, and dies after 2 or 3 seconds. This thing is testing my patience... Any other ideas?
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..BAD TO THE BONE..
