The 10ci quantum uses the same rings as the 13ci 5hp. or something.
Its coming back to me now.

The early vane with the vertical pull start. Thats 10ci

The later one is 12ci.



If thats the case, I must say, quick throw the whole mower in the bin before it eats your first born and bites you on the arse.
Those early 3.5 quantums are damn evil.