Originally Posted by codprawn
Many do - it all depends what country you are in. It is for environmental reasons rather than anything else!!!
We have imported modern 2 strokes Mariner/Tohatsu engines from USA, Panama, Japan and all their manuals stated 50:1 ratio, so for this brand, the geographical / environmental location is not an issue for going 100:1. For the moment, will stick with usual 50:1 untill there is a factory bulletin specifying so. Consult your owners manual for your 2 strokes engine brand before going 100:1 or repent forever for experimenting.