Three .50 sized fourstrokes.
Today I ran three different 50 sized fourstroke engines on WildCat 10% fuel/18% syn/castor blend.
Idle rpm all three 2,000
Enya .53TN, APC 12x6 rpm==9.550 Still in production. Stock Enya plug
OS .52, APC 12x6 rpm=====9,523 Last series of the .52, OS-f plug
Saito .50, APC 12x6 rpm====9,515 Last series of the .50, Fox Miracle plug