My Daughter's 90cc Arctic Cat 4wheeler starts nice, idles fine but will not hold high RPM long enough to move forward for more than 20feet.  Attempting to accelerate from idle moves the machine ahead but then it seems to run out of gas.  Accelerating quickly the machine will pull a wheely but quickly bogs out.

I have disassembled the carburettor twice and cleaned needle and seat and cleaned the one removable jet with brake cleaner. no change.  It seems like the carb is not filling up with enough fuel - I checked the fuel line by removing the line from the carb and allowing fuel to pour into a can - seems to have a good flow rate.

I have had this problem before and it was solved by cleaning the carb.  I never really found the problem.

I have ordered a new needle and seat for it just to make sure that is not the problem.

Any thoughts?  

check the tank valve, it could still have some trash in the tank and the fuel petcock clogging up.

other than that have you tried adjusting the fuel/air mixture?

if it is bogging down on high rpm's then normally that is a sign that it is getting too much fuel in the fuel/air mixture.

turning the fuel/air mixture screw to the right in 1/4 turn increments let it run for a few minutes between 1/4 turns and then ride it to see if it got better.
be sure to mark where it is setting originally and keep up with how many 1/4 turns you make in case you need to get it back to where it was and try the other direction.  

Thank you for the feedback wolf1.
I replaced the needle and seat with a new set last night just to ensure that is not the problem. I checked the fuel line and found good fuel flow.

Still have the same problem.

I will attempt to adjust the fuel/air mixture screw.
Does clockwise rotation of the screw increase fuel to air mixture?

I had this same problem before and it was solved by cleaning needle and seat.  problem went away and machine worked fine.  not so lucky this time.

The machine does seem to take the high RPM OK just not for long; I can pop wheelies and travel for maybe 20yards - acts like it is running out of fuel.

I could possibly adjust the float level.  Doesnt seem to make sense when the machine was working fine before.  

I will let you know how I make out with the air/fuel mixture screw.

ChrisM  

No adjustment on the jets 0n this carb.

Solved the problem though!
The hi-end jet was plugged.
Previously I cleaned what I could get at - last night I realized that there was a second jet behind a plug.
This turned out to be the hi-end jet and it was plugged with gunk.

Cleaned the jet and the machine works fine.

ChrisM  

My sons 90 arctic cat just started doing the same thing. Is the carb easy to get at and take apart and clean? thanks  

I had similar problems w2ith my yamaha, carbs were actually fine but the line for the breather on the carb was plugged by a dirt collecting bug. Also check the gas cap breather line. Good luck.  

Ive got a arctic cat 2003 300 2x4 with the same problems. We have cleaned the carb 3 times. and have adjusted the air/fuel screw multiple times as well. I am lost and help would be great.
Ryan  

Ryan,

I think the 300 has an air jet molded in to the carb housing and opens to the venturi side of the carp with the cavity leading to the bowl. It takes very little dirt to clog or restrict dissassemble carb clean and blow air through the cavity.
Second thing is to check and make sure the main and pilot jets are in the correct ports ( on some of the carbs they are similar in appearance.