high output engines!

[ericcs]

can someone explain how H.O. engines work. As we all know, several makes of engines have various HP models with H.O. variants, so how does it work. If say, my boat is rated to 100hp, and I put a 100HO engine on, it must then be over powered, as they all claim these versions have greater performance. So you would expect they have more HP than what the sticker says. I know there is up to a 10% either way fudge on HP figures, depending on brand, so my 100hp could actually be 110hp, and then by getting the HO version, it could be maybe 120hp?

[stevej]

There is an alowance of plus minus a few % on engine outputs
I thought it was 10 %
“I tried to google to back that claim up but couldn’t find it at this time”

You have engine of the same capacity same max revs with various hp labels and no other part differences and in some cases I think there is no difference hp wise as they are just playing with that above 10 percent figure

60hp labeled can be 55 or 66hp for example

But in answer to your question If the manufacturer states in its literature that the 100ho puts out 115 or 105. then yes the engine exceeds the capacity plate

[Noelm]

HO engines do not necessarily have more HP (contrary to popular belief) they develop their HP at a different RPM to a "normal" engine and can often suit certain boats better.

[Noelm]

Different engines sharing a common block is not new, and it has nothing to do with a 10% variance, there is lots of ways a common block can have multiple HP ratings.

[stevej]

the 115s are just detuned 130s at different levels then as its a 1.7l block as well

truth is you dont know what hp you are getting as no one puts out dyno figures

[Noelm]

Being the same block/capacity means nothing except SOME parts are interchangeable, lots of things can be different to obtain the extra HP, cams, heads, pistons, valves, exhaust ECU and various other parts can be different, on the same basic block, in the "old days" the 85/90/115 V4 Evinrude/Johnson all shared a common block, but, not all parts were the same, plenty say, "just change the carby jets" but that doesn't work, it just gives you a poor performing heap of crap. Motors like the 9.9 and 15HP are common powerheads, but, one is 50% more HP than the other, it's not black and white, and a lot of internet myth surrounds it all.

[stevej]

Capacity is everything but your welcome to your view

Even the guys on the etec forum say many parts are identical between the outboards sharing the same displacement

[myusernam]

No replacement for displacement

[Noelm]

That's not what it's a about, he is saying different HP engines have the same basic block (and capacity) not whether bigger is better or not.

[Dirtyfuzz]

I remember reading something about the Mercury 115 pro xs was actually 140hp at WOT but something about they only test the hp at a certain rev range to pass, bullshit or valid?


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[billfisher]

No replacement for displacement

Some of the HO engine do have a bigger displacement. Eg the HO Etec is a 4 cylinder whereas the regular 90 hp is a 3 cylinder.

[stevej]

in this case the 130 is 1.7l
the 115 and 115ho are also 1.7l so a detuned 130hp, or most likely just a 130 spec with a 115 ho sticker

[ericcs]

There is an alowance of plus minus a few % on engine outputs
I thought it was 10 %
“I tried to google to back that claim up but couldn’t find it at this time”

You have engine of the same capacity same max revs with various hp labels and no other part differences and in some cases I think there is no difference hp wise as they are just playing with that above 10 percent figure

60hp labeled can be 55 or 66hp for example

But in answer to your question If the manufacturer states in its literature that the 100ho puts out 115 or 105. then yes the engine exceeds the capacity plate

I remember 10% was the tolerance. Back in the day, the Evinrude/Johnson's were more than the sticker said, because they were rated at the prop. other brsnds were at the powerhead.

[Chimo]

"in this case the 130 is 1.7l
the 115 and 115ho are also 1.7l so a detuned 130hp, or most likely just a 130 spec with a 115 ho sticker"

These are the G1 motors I believe.

But
The new G2 115 140 and 150 are 1.9 lt 3 cylinder motors and the 115 is in fact a 115HO only.

They apparently can be had with or without the built in steering.

The price is apparently not released as yet

If thats changed what are the numbers?

[Bremic]

I remember reading something about the Mercury 115 pro xs was actually 140hp at WOT but something about they only test the hp at a certain rev range to pass, bullshit or valid?


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Surely the max horsepower will be reached at WOT, certainly not half way up the rev range.