SHO?

Whats the difference in the Yamaha 4 stroke and the “SHO” motor?

Performance. The sho is a cranked up version of the 4 stroke

I believe variable timing, weight, different valving, in some cases I believe the lower units have different ratios.

Depends on the size you are looking at. In the 225 & 250 hp versions the only difference is the non-SHO alternative is the off-shore model which is an identical 4.2L V6 except the offshore has a larger alternator, beefier motor mount and more saltwater corrosion protection. Also the SHO is black instead of grey. In 200 hp the difference is significant, the SHO is still the same 4.6L V6 as the 225 or 250 but the only non-SHO 200 hp motor they make is an inline 4. Looking at the Yamaha website there doesn’t appear to be any difference in the 175 and below SHO/non-SHO motors except for the color of the engine cover. Same displacements, compression ratios and gear ratios. The only exception is the 150hp where they still make the original 2.7L 150hp mechanical control version along with a 2.8L digital control version and the SHO model.

Bass-n-Eyes wrote:

Depends on the size you are looking at. In the 225 & 250 hp versions the only difference is the non-SHO alternative is the off-shore model which is an identical 4.2L V6 except the offshore has a larger alternator, beefier motor mount and more saltwater corrosion protection. Also the SHO is black instead of grey. In 200 hp the difference is significant, the SHO is still the same 4.6L V6 as the 225 or 250 but the only non-SHO 200 hp motor they make is an inline 4. Looking at the Yamaha website there doesn’t appear to be any difference in the 175 and below SHO/non-SHO motors except for the color of the engine cover. Same displacements, compression ratios and gear ratios. The only exception is the 150hp where they still make the original 2.7L 150hp mechanical control version along with a 2.8L digital control version and the SHO model.

It’s funny how they’ll use the same motor and just increase compression and/or RPM’s to change the HP and model.

My parents just bought a pontoon with a 90 hp SHO. Traded the pontoon back in for a fishing model (duh) and the new one had a 90 hp Yamaha 4 stroke

Are you saying there is no difference between the two?

I believe the H.P.on any of the manufacturers that have high output motors
cab be as much as 9% more H.P. than what is stated.

lindyrig79 wrote:

Are you saying there is no difference between the two?

Looks like the published specs are the same

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Weird. Wonder if there’s a premium price for a black cover?

marineman wrote:

Looks like the published specs are the same

Thanks. I’m not an engine guy, but that does seem odd. At least I was somewhat right in telling them I’d prefer the standard 4 stroke (in my mind anyway)

You need to expand all the specs biggest difference is the gear ratio standard 90 is 2.15:1 the SHO is 2.33:1 Plus from my experience the SHO’s run higher rpm.

Ummm- S.upper H.igh O.utput, like the 90’s Ford Taurus SHO _but not your Grandma’s Taurus!