Mercury as well as most outboard manufactures have a number of different shaft lenths to fit different applications here is how you measure get a standard tape and measure up from the cavitation plate on the leg up to the bottom point on the powerhead, common lenths are 15" (short shaft) 20" (long shaft) and 25"(extra long) hope this helps
Yes. The ELPTO stands for (EL)ectric start (P)ower (T)rim (O)il injected
If not using the factory supplied oil injection, use a 50:1 ratio. This is roughly one pint of 2 cycle oil, to six gallons of fuel.
Electric Start, Long Shaft, Power Trim, Oil InjectionTwo Stoke means a two cycle engine. An engine that fires on each upstroke.
I have a 19' Crestline with a Mercury 50 ELPTO that has a 12X101/2 Turningpoint prop. Max speed with (2) aboard is 23 MPH by GPS @ 5600 RPM in ideal conditions. I crusie at 4000 RPM at about 13.5 MPH burning 2.5 gallons per hour. Max speed drops to 20 MPH with (5) aboard and will crusie at 12.5 MPH at 4000.