75 vs 90 Yamaha on a 170

[HIFLUTIN]

Wanted to put a 90 Yammy on my 170
Stumbled on a 75 at a good deal.
I believe they are the same block/diff carbs.
Any input on any other differences & perfomance/results for my 170
Thanks

[flounderpounder225]

Wanted to put a 90 Yammy on my 170
Stumbled on a 75 at a good deal.
I believe they are the same block/diff carbs.
Any input on any other differences & perfomance/results for my 170
Thanks

Both great motors and fuel efficient, if the 75 is a great bargain, I would jump on it, the 15 hp is not going to be THAT big of a difference.

[akbridge]

If its a steal get it.  If its not the performance you want, sell it and get something bigger.  I believe it will perform well.  You should see speeds around 35 mph.

[Bobber]

Are you comparing 2 or 4 strokes?

The old 2 stroke C75 was the same block as the 2S 90, not oil injected and had the lowest compression ratio of any modern outboard which means it can run well on 82 octane fuel - it was very popular with boat rental places as a result. Its main drawback was that up until the late 90's its steering yoke and shift shaft were not stainless and prone to failure.

[HIFLUTIN]

Are you comparing 2 or 4 strokes?

The old 2 stroke C75 was the same block as the 2S 90, not oil injected and had the lowest compression ratio of any modern outboard which means it can run well on 82 octane fuel - it was very popular with boat rental places as a result. Its main drawback was that up until the late 90's its steering yoke and shift shaft were not stainless and prone to failure.

Its a 2 stroke
Thanks for the reply

[Bobber]

I had a 1994 C 75 on a KW 1720, bit lighter than your 170 - with just me, full fuel and gear and a stock aluminum 17p prop it would barely hit 35mph on the GPS @ 5500 rpm, 32mph with 3 aboard. Added a doel-fin (no tabs) which cut it back a few mph but it planed out easily with 3 aboard. Cruised at 4500rpm @ 28mph, about 4 mpg if memory serves. Great motor, ran smooth for a 3cyl looper but a real biatch to start cold on a cold morning. Only problem I ever had with it was the notorious 3cyl Yammy TNT drift.