UK Karting - Notice Board (2-Stroke Karting) : Re: Rotax Max Carb

Notice Board (2-Stroke Karting)

Re: Rotax Max Carb
Posted by 'alanrr' on 18 May 2016 @ 22:50

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alanrrJoined: August 2001
Total Posts: 491
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The default position of the air screw is two turns (anticlockwise) from the fully closed position. This works most of the time but I will describe the adjustment procedure for getting better results.

Firstly, the engine can’t be cold for this adjustment. It’s necessary to adjust the carburettor with engine at operational temperature, between 45ºC and 65ºC so bring it up to temperature first.

The starting point for the throttle stop screw is not definable as all carbs vary but you can look down the carb with the airbox off and watch the point at which it starts to raise the slide for a starting point.

With the engine stopped, close the air screw turning it in fully but not too tightly and open it two turns. This is the default position. This is the position we need in order to adjust throttle stop screw.

Start the engine and adjust throttle stop screw to get the engine idling but the revs as low possible at around 1200-1400 rpm. You may find the engine keeps stalling until you get this step right.

Once you've adjusted the throttle stop screw, stop the engine, close air screw and open it about 1.5 turns. Now you're going to have to listen to your engine.

Start the engine and slowly open the air screw till you get a smooth sound to the engine. Open the air screw by a 1/4 turn each time till the engine runs smoothly and the revs should rise to a bit higher than with the standard position.

If it revs too high, you can bring the revs down with the throttle stop screw.

You're looking for the highest revs by adjusting the air screw and then reducing the revs on the throttle stop screw.

Be aware that it's an air screw and not a mixture screw, so as you turn it out you are leaning the mixture not enriching it.

You shouldn't have to wind it out more than aboit 4 turns as it can come loose out on the track.

It may be that there's an obstruction if you can't get it to idle nicely.

Message Thread:

Rotax Max Carb by 'Stevetony' (18 May 2016 @ 10:21)

Re: Rotax Max Carb by 'Stevetony' (18 May 2016 @ 13:53)

Re: Rotax Max Carb by 'alanrr' << You are here!

Re: Rotax Max Carb by 'alanrr' (18 May 2016 @ 22:53)

Re: Rotax Max Carb by 'Stevetony' (19 May 2016 @ 6:33)

Re: Rotax Max Carb by 'TeamPoor' (19 May 2016 @ 12:52)

Re: Rotax Max Carb by 'alanrr' (19 May 2016 @ 21:52)

Re: Rotax Max Carb by 'Stevetony' (20 May 2016 @ 12:01)

Re: Rotax Max Carb by 'alanrr' (20 May 2016 @ 19:48)

Re: Rotax Max Carb by 'TeamPoor' (23 May 2016 @ 13:10)

Re: Rotax Max Carb by 'alanrr' (24 May 2016 @ 10:25)

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