Thanks for the info -
I agree from my post - the richening has prob been about 1/2 a turn in total, certainly not 2 turns - but the positions are not changing in flight.

First to check will be the pickup - Is there much adjustment there ? as the magnet (1) and mounting screws for the sensor are fixed ?

It has certainly picked up RPM - now pulling 7000 on a 24x10 Menz

Which leads to my 2nd problem of noise - over 100db at 3 metres - which is a problem with my new airfield having noise restriction at 95db
I hope to fix with a different prop, and will be trying a 24x12 3w and 26x10 Menx next

Would you class the MVVS canister a muffler or as a pipe, as I have plenty of horses - I may have to change ..

Have you any thoughts on my predicament

Model - Composite ARF 2.3 Extra

Best regards
Dominic