Jetronic air flow meter sticky to move

[pentoman]

I just purchased a complete injection/intake unit for a 2.5-16. It's all still together in one piece, just removed from another 2.5-16 and consists of air flow meter, fuel distributor, most of the fuel pipes, intake pipes, EHA etc. This is because I have a problem with saggy throttle response on my own 2.5-16.

I have noticed the air flow meter flap is very easy to move on the spare unit. A world different from that on my car which is comparatively much stickier. I think that this must be my problem. To explain: Mine comes up to rest position easily enough but requires more pressure to go down. But worse than that when you push the plate down you can feel it's pushing against something else giving it extra resistance (presumably this is the plunger in the distributor sticking). So if you push the plate down with your finger then let the pressure off, the air plate itself will come up very quickly right along with your finger, but the plunger does not - you can feel the delay of 1-2 seconds before the plunger catches up and you feel a 'bump' when it does catch up and hits the air flow meter arm. Also during this period you can very freely operate the air flow flap and the resistance of the plunger against it has disappeared.

Is this normal? Perhaps there's something I'm not understanding, because I'm comparing an air flow meter that's off the car with one that's on the car? I did remove the fuel pressure by unplugging the fuel pump relay and turning the car over(amazingly it ran for a second or two) but it made no difference, it's definitely sticky. While I was there I adjusted the plate to make sure it's central and resting properly.

How would I best fix this stickyness - transfer the whole spare airflowmeter/distributor/etc in one piece over? Or take mine apart to try to diagnose? Lubrication?(!)

Yours excitedly (chasing the prob for 18 months!)