Speed is dependant on a number of factors. Most importantly the size, type and weight of the boat that it is on and the number of people on board. A 50 HP outboard will push a small aluminum fishing boat a lot fast than it will a 20 ft fiberglass boat.
I have a 50 HP 2 stroke that will push a 16 foot aluminum boat 35 MPH.
What mph compare to a 3.3 horse power outboard motor
8-15
It depends on the size craft it is pushing. A 5hp outboard should run fast enough to plane out say a 10 to 12ft. aluminum boat with one man aboard.
50 mph
A 3.5hp outboard will give you 8mph tops, which would be a normal walk to a slow jog.
You will notice on the throttle handle that there are three positions on the legend. "Really Slow", "Start" and "Slow".
I have a 14/36 flat boat with a 15 and it goes 26mph with only me and minimal gear.
it has a shaft that go in the motor that moves the boat =-Þ
on my avon air floor inflatable in okinawa with 2 and fishing gear about 4 to 6 mph. avon 310
just stay with the 50 to 1 ratio and you can't go wrong.
carburator jets clogged!
I have a 1980,115 Johnson Outboard on a Very Heavy 16ft Crestliner Fiberglass boat,I can get it up to 62kms per hour with 4 people in it .(I used a GPS to test this )