Difference between Yamaha f90la and a yamahaf115la

[Bsr3470]

Difference between Yamaha 90 and Yamaha 115

I have a 2013 Bennington 20ss with a f90la which is pretty much the same as a f115la. So I bought a ECU for a 115 and installed it. It runs rough but runs at top end but I lost rpms. Is they're anything else I need to replace to turn my 90 into a 115 or adjustment I can make

 

[Bsr3470]

I have a 2013 Bennington 20ss with a f90la which is pretty much the same as a f115la. So I bought a ECU for a 115 and installed it. It runs rough but runs at top end but I lost rpms. Is they're anything else I need to replace to turn my 90 into a 115 or adjustment I can make

 

[racerone]

Are you sure 115 hp model is the same displacement as a 90 hp model , yes or no ?

 

[GA_Boater]

According to Yamaha both are 1.8L. But what about cams, pistons and head? Over 20 pound difference in weight too.

I don't know.

 

[boscoe99]

How in the world did you come to the conclusion that you could use an F115LA ECU in an F90LA?

Different block.
Different crank shaft.
Different head.
Different throttle body.
Different VST.
Different fuel injectors.
Different mid section.
Different lower unit.
Different wire harness.

Other than just about everything, as you say the F90LA is pretty much the same as the F115LA.

 

[boscoe99]

According to Yamaha both are 1.8L. But what about cams, pistons and head? Over 20 pound difference in weight too.

I don't know.

 

[racerone]

I can't believe that Bsr3470 did not check this out.-----Bought parts on line or consulted a dealer / shop ???

 

[GA_Boater]

Yamaha side by side comparison is where I got the 1.8L and weight difference. It's the same for the Mid-Range 115/10 and the Max SHO motors. Like I said - I don't know. Maybe newer can't be compared to a few years older. I'm learning.

I guess the way "to turn my 90 into a 115" is to replace the 90 with a 115.

 

[racerone]

Post # 3 is a reflection of looking it up.----The 90 HP has a displacement of 1.6 liter for 2013 and shares parts with the 75 HP model , not the 115 HP motor !!

 

[GA_Boater]

I agree racer. I was showing where I got my misinformed info. Still learning.