If the spring was broken the needle would go right around and stay at the other end just under the 0.
Send it to me John i'll fix it for you, better yet send both speedo and tach, ill do a refurb for you on them.
FWIW Theres a special on Nimbus 2000 repairs this week only.
PM me about this,,,,,,,,,,,,,,,,,,,,,,if you dare to,,LOL