Idle mixture screw!

I have tried putting a long 3mm Allen key into the hole and feel the screw but the Allen key just spins tried a 4mm but that wouldn't sit in the hole on top of the screw!
Is there a special tool needed or is mine just fubar? If it is are these still available anywhere?

 

Should be 3mm, how long is the one your using? Might be bunged up with gunk..

 

It's a t handle one and it's about 6". It's deffinately long enough just hoping its not rounded!!
If it is full of gunk how will I clean it? I need to adjust the idle mixture as the tickover is lumpy and out!

 

Has your allen key the ball-type end or the flat one? The screw recess is fairly shallow, and a flat-ended allen key will fit better.

i.e. this:



will grip better than this:

 

It's not the ball type it's the flat type alexis!

 

Squirt it out with carby cleaner. If there's enough room, we use cleaning gum (blue tack) to lift out the grit. you'd be hard pushed to round off a 3mm hex.

 

That's what I was thinking about the rounding off. It's too small and shouldn't be tight enough to round off! Ive got some carb cleaner so I'll try that first! Shame you can't see enough through the little hole to see what's going on! Could always take the airbox of the metering head and take a look!

 

Right I've had a look down the hole at the mixture screw and I can tell you that there is no 3mm hex head in there? To me it looks like it has been drilled slightly!! Wtf

 

Cheers rj. I'm going to have a look tonight if the rain holds off! I'm hoping it is just full of crud and not completely drilled out!!

 

Right I've had the metering head off the airbox and I can see the idle screw but not the top of it! I can see that 2 circlips on the out side of the metering head at each end of the pivot for the metering flap! So how do I get the flap and arm out to gain access to the screw?
I've tried searching but haven't found anything! Does anyone know how? Rj??

 

Brilliant cheers rubjonny! Yeah I know it's for setting mixture at idle just need to set the Co as I've had an abf fitted and want the Rickover to be nice and smooth and not lumpy like it is.
I've checked for vacuum leaks and have sorted any so my last port of call is the idle mixture!
Ill let you know the progress as and when!
Do you reckon it may be a good idea to document the strip and rebuild?

 

When I get round to doing it I shall take as many pics as I can! Did you disconnect the fuel lines as I don't really want to go down that route!

 

Excellent thanks for your help and advice Rj! I'll get on to it as soon as I can!

 

I had to strip my metering head down years ago due to the same problem, you need to be able to turn the adjuster screw without putting pressure on it to set the mixture correctly.

 

Thanks for the tip Keith

 

If your metering head is dead then TSR can get hold of new ones, 300 + vat though :/