Carb crisis! By shibz02 (Read 718 times)

[shibz02]

I'm a long time reader but a first time poster. I recently purchased a new roketa 150cc scooter. I am not a mechanic but, due to various circumstances, I decided to do the PDI myself. After doing the basics such as changing the fluids and checking the tire pressure, I started to drive the scoot around and wracked up about 300km. I noticed the scoot would loose some power at intermittant intervals at high speeds. This weekend I decided that because my scooter was an 08' and I bought it new that it must have sat too long and the carb was dirty or the fuel lines/filter needed to be replaced. I took the carb out and cleaned it just like the video that the big guy posted. When i put it back in i replaced the fuel lines with 1/4" premium lines and new fuel filters. My work fixed the problem I was having at high speeds. However, I created a new one. Now when ever I start the scoot it dies unless I immediately start driving. After it has been driven around the block it will stay on but it will idle very strangely. Sometimes in excess of 2300 or as low as 1000 rpm. It also will fluctuate over time. Some notes that stand out to me: 1. The float didn't really bounce while it was upside down. Only when it was hanging down. 2. The enricher seems to not screw all the way down but it still works. 3. The fuel lines at 1/4" seem to be bigger than they should be for some of the nipples. 4. I didn't replace the vac lines.

How can I fix this?

[sprocket]

Hmmmmm...Did you change the air/fuel mixture screw when you took it apart? Usually this is
a cause for weird idling...did you remove this screw when you cleaned the carb?

The enricher part with the O-ring should be all the way in the hole...

1/4 fuel lines are too large they should be 3/16 ID... but it doesn't matter as long as it doesn't leak.

Things point to the enricher...need to check it out...

[kountryguy]

I do not know the answer to your questions, but it sounds like I am having the same problem with the same scoot. I have not as many miles yet, but at higher speeds, it just quits. Let it sit a couple minutes and it will start right up and run fine again. Your experience is why I have been reluctant to tear it apart. Good luck, let us know how you make out. Thanks

[sprocket]

kountryguy.. how does it quit? Just stops.. like you turned off the key?

What year is it and how many miles?

Over 800-1000 miles you need to set the valve gap... it is due and will rule out tight valves...

.004 INCH intake... .005 INCH exhaust

[kountryguy]

Like Shibz02 mine is a "new" 2008 Roketa MC-70-150. I only have about 125km on it. When it dies it sounds like the key is shut off, but if I am going downhill, sometimes it will restart. However it usually happens on the level or uphill and as soon as I maintain rpm's above 5000. I do not want to steal this thread. I have a thread going also. Thanks for any ideas.

[shibz02]

Jun 12, 2011 14:35:04 GMT -6 sprocket said:

Hmmmmm...Did you change the air/fuel mixture screw when you took it apart? Usually this is
a cause for weird idling...did you remove this screw when you cleaned the carb?

The enricher part with the O-ring should be all the way in the hole...

1/4 fuel lines are too large they should be 3/16 ID... but it doesn't matter as long as it doesn't leak.

Things point to the enricher...need to check it out...

Thanks for the fast response. I forgot to mention that I set the fuel to air ratio screw and idle screws before as part of my original PDI. Per the PDI instructions, I set the idle to 2000 then slowly turned the mixture screw until i thought it was at what they called peak rpms.

I did not however, take the screw out when I cleaned the carb. Should I have?

Also I don't think the enricher is fully seated because i put it on after the carb was installed rather than when I was finished cleaning it. I also think i bent the ring that goes around it. Its so flimsey!

[sprocket]

Yes.. you can still do it now. You should give it a really good couple of shots of carb cleaner from a spray can with a straw...

Be careful, there is a TINY rubber O-ring in there, a TINY washer and a VERY SMALL spring...don't loose
any part... The order is O-ring, metal washer, spring and screw..from the in to the outside...

YOu can do it on the engine. Loosen both carb brackets and turn the carb so the air fuel mixture screw is up and remove it. then give it some blasts. Put everything back in and set the screw to 2.5 turns out and then do through the adjustment of the A/F screw like before...