The primary reason a gear meter won't count is that the gears are not moving. Once you have ensured that the filter is clean, and all necessary valves are open (main valves, product valves, throttle valves, etc.) to allow flow, it may be necessary to *carefully* open the gear meter to check for obstructions in the gears themselves.

If you have opened the gears previously -and especially if recently- it may be that the gears were inserted 'upside down'; always make sure that BOTH gears have the magnets (two small circular magnets per gear) facing OUTWARD and that the gears spin freely with little force by hand.

Lastly, always lightly, but firmly, tighten the face plate back on (we don't have a torque spec for this); allow the o-ring/gasket to do its job, don't over-tighten!

Here is a link to Gear Meter Repair