Outer Limits 4x4 Board

my speedo flickers and sticks all the time. so i aquired a new one, trouble is it starts off at 15km/hr and appears to stay 15 out all the way up.

my main question is is there a zero adjustment on these speedos?
also i put some contact cleaner on the old one n got rid of some corrosion. it now works but flickers badly at over 80 any other hints?

Not sure about GQs but when I had my MQ speedo out (a long time ago now) I seem to recall thatI zeroed it by simply moving the needle on the spindle!

Also a flickering needle can be caused by lack of lubrication of the cable or a kinked or pinched cable.

Cheers