UK Karting - Notice Board (2-Stroke Karting) : Strange Carb Problem on Rotax Max.

Notice Board (2-Stroke Karting)

Strange Carb Problem on Rotax Max.
Posted by 'PhilipBaker' on 18 Apr 2011 @ 10:01

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PhilipBakerJoined: May 2009
Total Posts: 1
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Last month at practice I had a very strange carb problem on my Rotax Max. It gets to around 10-11K rpm and then hesitates, it doesn't pull through this to rev any higher, so I'm stuck spluttering along at 10-11K's. It feels like it's starving of fuel.
I eventually tracked down the issue to the rubber overflow pipe that goes over the top of the carb. Prior to this I had stripped the carb, the fuel pump, the PV and replaced the battery to try and eliminate the issue, but no joy. Eventually I tried someone else's carb and it was OK so again I rechecked my own carb, went back out but still no good. In the last practice session of the day I pulled off the track and decided to pull off the rubber overflow pipe, went back out and magic, worked as normal.
I was expecting the pipe to be blocked somewhere but I could see nothing wrong but bought a new one anyway. I cut out a section in the middle of the pipe about 1 inch long as you do and put this new one on. I also had the carb ultrasonic cleaned. Went practice on Saturday and exactly the same issue! What the??? Pulled off the rubber tube and back to normal 14K+ revs.
I really cant work this one out, why would the carb work without the pipe but will not work with it on. I could understand if there was no cutout and I even made it longer to allow more airflow but still it made no difference. Can anyone explain this strange behaviour as I can't understand this one?
It also works fine with 2 seperate tubes, so I can solve this but I would really like to understand this.

Message Thread:

Strange Carb Problem on Rotax Max. by 'PhilipBaker' << You are here!

Re: Strange Carb Problem on Rotax Max. by 'ScoobyScene' (18 Apr 2011 @ 10:27)

Re: Strange Carb Problem on Rotax Max. by 'Superslow' (18 Apr 2011 @ 14:28)

Re: Strange Carb Problem on Rotax Max. by 'PhilipBaker' (18 Apr 2011 @ 14:28)

Re: Strange Carb Problem on Rotax Max. by 'Vincemax' (18 Apr 2011 @ 15:53)

New Paddle, New Needle by 'ScoobyScene' (18 Apr 2011 @ 17:49)

Re: New Paddle, New Needle by 'PhilipBaker' (19 Apr 2011 @ 9:54)

Re: Strange Carb Problem on Rotax Max. by 'Jazpas' (18 Apr 2011 @ 16:06)

Re: Strange Carb Problem on Rotax Max. by 'PhilipBaker' (19 Apr 2011 @ 9:58)

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