l. I have a 2000 model Yamaha 2hp motor and the manual says use 100:1 ratio, but the shop that sold it to me said use 50:1 as the engine will last a lot longer. Who is right, the manual or the shop? 2. I also have 2 old Evinrudes, 1957 5.5hp, and 1968 3hp. Can I use 50:1 in these motors and if not, is it because the alloys, bearings, etc. used back then were not as hard as today's products? Thanks for helping me increase my knowledge. I have another question which I will post seperately because this one is already pretty long.
