Fuel/Oil Mix Ratio.-

[Sea Rider]

Was wondering in which year did Yam started using 100:1 fuel/oil ratio on their 2 strokes 8 HP motors ?

Is there a missing collar that holds in place the thermostat inside cylinder head, or this model only uses a thermo without collar. Someone stole what was inside..




Year is unknown, but it's a 8 HP with non exhaust through hub motor powered by a 3 blade prop with end cone.

Happy Boating

 

[robert graham]

I believe the 100:1 ratio was a short- lived experiment by Yamaha years ago and the long since recommend 50:1 Seems the 100:1 didn't provide adequate corrosion protection while motor was off......

 

[boscoe99]

I believe the 100:1 ratio was a short- lived experiment by Yamaha years ago and the long since recommend 50:1 Seems the 100:1 didn't provide adequate corrosion protection while motor was off......

Au contraire Robert. Many, many, many Yamaha two strokes are designed to run on a 100:1 fuelil ratio. Some of the last two stroke pre-mix models offered by Yamaha USA specify a 100:1 ratio.

I remember the day when 25:1 was the norm. When 50:1 motors came along there were folks who could not believe that so little oil was being added to the gasoline. They would throw in some extra.

As a point of interest, for whatever it is worth, a number of the large HP Precision Blend Models (oil injection) function on a 200:1 ratio at idle. The point at which they get to 50:1 is not known to me.

 

[boscoe99]

Was wondering in which year did Yam started using 100:1 fuel/oil ratio on their 2 strokes 8 HP motors ?

Is there a missing collar that holds in place the thermostat inside cylinder head, or this model only uses a thermo without collar. Someone stole what was inside..




Year is unknown, but it's a 8 HP with non exhaust through hub motor powered by a 3 blade prop with end cone.

Happy Boating

What is the ID on the motor? If nothing is there, look at the CDI. What markings are on it?

All of the USA 8 HP models (1984 ~ 2009) show the use of a collar.