Where are the screws on carburetor for adjusting

Carburettor will probably need tuning, often there are three screws; one is a throttle stop screw to adjust the idle speed and two to control the fuel, one for low speed and one for high speed. Successful adjustment takes time and requires much patience as adjustment of each screw affects the other to some extent.

It isn't usual with small high speed engines but it is worth checking the exhaust is not strangled.

There are quite a few reasons. What motorcycle do you have?

you need to tell me what make and model your bike is as it depends where the air screw is

Find the adjustment screws on the front of the carburetor. Then Start the engine and let it warm to normal operating.
Adjust both screws equally and find the right mixture.Bring both screws up slowly and listen until the engine purrs smoothly. Any raggedness or rattling is a sign of too lean a mixture. Keep turning until you find the sweet spot.

Hello,
Check this site: http://tekindoor.com/miscellaneous/stihl-chainsaw-carburetor-adjustment/

Theher is good information.

There is no adjuster for the Husqvarna 450. Husqvarna recommend that if there's not enough oil reaching the bar that you slow down the engine by adjusting the carburettor screw. I have the same saw and also wanted to adjust the oil flow. I didn't change the carburettor and it's still cutting away without doing any damage. It's meant to use less than a tank full of oil to the tank full of fuel when you're cutting near constantly. With stops in between it will use more fuel and less oil.

Firstly consult your manual regarding carburettor settings. There should be a high and low speed adjustment on the saw, often called or labeled as "L" and "H".

These are often located on the main motor body, closer to the handle on one side and require a screwdriver or similar to adjust. They might be buried and you have to look down the adjustment holes in the outer body to see the screws.

Basically you need to adjust the "L" or low idle screw.

Firstly, warm up the chainsaw and allow it to get up to temperature... The blade, as you say will probably be spinning still with hands off the throttle... Grab your screwdriver and adjust the "L" or low idle screw turning it counter-clockwise (at least on most saws) very slowly until the chain just stops turning on the bar. If you go to far you may stall the motor. You just want the chain to have just stopped moving on the bar, and that is your "L" setting position...

Has to be done with a warm engine though.

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