Where is the adjuster screw for the carburettor ?

oe screw is for idle and the other is for rpms
hold the throttle at the point it starts to sop and adjust the high speed screw until you can keep increasing the throttle
won't be much off the setting it is now

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.

Problem with Cars & Trucks
Air fuel mixture screw adjustment of spaco 17d carburettor Open Question

Drill a small hole in center of welch plug and run in a sheet metal screw and pull.

Some ATCO carburettors have more than one hole for attaching the throttle cable to the governor pivot, which will allow some variation of the speed setting by moving to a different hole.
Just before the throttle cable reaches the governor pivot it passes through a metal lug (separated from the pivot by a spring) here there is threaded screw on the throttle cable - loosen or tighten this to adjust running speed.
There is also a throttle stop adjusting screw which on the side of the carburettor which you can adjust to set the idle speed.

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.

I can help with this.
On the earliest models they had slide type carburettors. This is to say that the slides were actuated by the throttle cable acting on a linkage that physically lifts the slides in the carburettors. This type of carburettor has its balance(syncronization) adjusters under the caps on top of the carburettors.(the cap isn't round & has 3 screws in it)
Number three carburettor is fixed & dosn't get adjusted.

You'll have to put the bike next to a bench & attatch a long piece of fuel hose from the tank to the fuel hose on the carburettors.You can join the two pipes together using a short piece of hose that snuggly fits on the outside or inside of the two hoses. You can also join them with a suitable shirt piece of metal pipe,or what is called here in Australia a P3 barb.These are available from tool suppliers that supply air compressor hoses & fittings.
(I made a remote tank from an old lawnmower petrol tank,a long piece of hose & mounted it on a tall stand.Under it I have a tray with all my different adaptors in it.)

You adjust number 2 cylinder to the same vacume reading as number 3 cylinder first.
Now adjust number 1 cylinder to the same vacume reading as number 2 cylinder.
Next adjust number 4 cylinder to the same vacume reading as number 3 cylinder.
Recheck that they are all the same & your done.
The adjusters are of the screw & locknut(8mm)type.
You can struggle with an 8 mm ring spanner & a flat bladed screwdriver,buy an adjusting tool(genuine, or non-genuine from a bike shop) or make one.

To make one you weld a bar onto the side(at the top)of an 8mm extended quarter inch drive socket.Then find a long small screwdriver that will fit down the hole.

After you make each adjustment,stop the engine & open the throttle wide open & release a couple of times.(This seats the slide).After diong this re-start the engine & re-check your adjustment.
I place a fan blowing on the engine to help control the engine temperature as the adjustment can be a bit of a fiddle.

I prefer to use mercuary type vacume guages as they dont go out of calibration.

If you are using dial type guages check that they are all reading the same by checking them all one by one on the same cylinder.
Some Suzukis' have a pipe (covered with a black rubber stopper) at the top of each carburettor(at the front) & others have an allen screw on the cylinder in front of the carburettor manifold rubber.
If yours has the allen screw you will also need adaptors that screw into the hole once the allen screw is removed.

If you bike has diaphram type carburettors on it(you'll be able to recognise this by the top caps of the carburettors being black & roundish in shape & held in place by 4 screws), the adjusting screws are between each carburettor & are the spring loaded type.
The adjusters are located in-between each pair of carburettors visable from the top.
These are easier to adjust as there is no lock nut to struggle with & all you need to turn the adjusting screws is a long (flat or phillips)screwdriver.
Again, balance the center two first,then the left pair then the right pair.

This procedure is applicable to all in line 4 cylinder motorcycles (even most fuel injected ones.

Regards Andrew Porrelli

Would this be the 1108cc or 1372cc model Uno ? You will find the vacuum advance unit attached to the distributor. Check the pipe connection from the vacuum advance to the carburettor - loose or damaged. This is normally the main cause for uneven idling/stalling. Alternatively the carburettor needs adjustment via the carburettor idling screw. Hopefully this will help. Good luck.

it shouldn't be all that special it'seither a small flat tip screw driver or its usually a torques screw either one should be avalible at any hardware store or toolstore