Outboards 2009 - HP, Weight, Make Comparison

[Wynand N]

Originally Posted by mwatts

Are the Tohatsu's in the chart the 4-strokes or the 2-stroke Direct Injected (TLDI) engines?

Looked a bit mixed in the charts;

25hp is on par for the plain two stroke short shaft
30hp at 72kg is a four stroke shorty (71.5kg)
40hp is a TLDi two stroke (93.5kg) short
50hp also TLDi two stroke at 93.5kg (plain two stroke short = 72kg!)
70hp is a TDLi two stroke at 143kg - long
90hp also TDLi two stroke at 143kg - long
115 is a TDLi two stroke at 173kg - long

Just for the interest, here are some weights of plain two strokes by Tohatsu

70hp = 105.5kg - long
90hp = 135kg - long
115hp / 120hp = 164kg - long
140hp = 164kg - long

[rwatson]

They must have a special South African Models

http://www.tohatsu.com/outboards/115tldi_spec.html
quotes the 115 hp as 178 kilos, dont know where you got 173, but not a lot of difference

All the other weights on the chart were spot on, but rounded up to next Kilo.

The two stroke figures are now included on the chart. They look about on par with the Yamaha.

I was a bit worried about the figure for the 140 HP 2 stroke, even the Yamaha 115 weighs 193. But according to http://www.tohatsu-outboards.com/tohatsu-140-HP.htm, that is correct

WHOOPS - READ THE FINE PRINT, THE 140 2HP IS NO LONGER AVAILABLE ACCORDING TO THAT LAST WEB SITE

[tom28571]

Originally Posted by rwatson

Hmm, can we not trust the facts quoted by manufacturers ? They get validated by lots of different people. I wouldnt have thought they would fib much.


yes - whats the point you want to make ?


I really am not sure what you mean by this. Could you explain more please ?


No - its only the 60 that is "much heavier"
The Suzuki 60 is 1298cm Displacement, and weighs 160 kilos, way over comparable motors. I cant think of when weight isnt a factor, but I would be interested in how the weight makes it more rugged. I have no experience with that engine.

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Outboard manufacturers have often fibbed about their power ratings. Maybe not so much now as in the past.
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The point is that many people always assume that 4 strokes are much heavier than 2 strokes. I only point out that this is not always so.
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Only what I said above.
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Since the Suzuki 60 appears to be the same motor as its much more powerful sisters, it appears to be a detuned version. Detuned engines are generally considered to be more reliable and rugged than their more optimized competitors. Ask any mechanic, especially those responsible for racing engines.

I am not challenging any of the data or statements you made and thought my comments were self explanatory. I do deal with outboards regularly and am interested in comparisons. I do trust the weights given by manufacturers but when specifying a motor of given power for a boat, need to look closely at the specs of those available to avoid space and weight problems.
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[rwatson]

I wasnt "having a go" at you Tom, just trying to educate myself a bit

Originally Posted by tom28571

Outboard manufacturers have often fibbed about their power ratings. Maybe not so much now as in the past.

I guess we will have to apply some faith in consumer law till we can do some tests. The thing I would like to see is the power curve of each of the engines. Maximum power at high revs makes for a short lived engine.

What we need is a separate authority to test newly purchased outboards to verify the figures. This would confirm to the buyer that the engine they bought was up to spec, and provide realistic HP figures.

Originally Posted by tom28571

The point is that many people always assume that 4 strokes are much heavier than 2 strokes. I only point out that this is not always so..

Well, if they arent heavier than two strokes, basic engineering principles mean there is a problem with one of the engines.

Originally Posted by tom28571

Since the Suzuki 60 appears to be the same motor as its much more powerful sisters, it appears to be a detuned version. Detuned engines are generally considered to be more reliable and rugged than their more optimized competitors. Ask any mechanic, especially those responsible for racing engines.

Re the Suzuki 60, the 60,70,80 and 90 are all 4 cylnders
The 60 Hp = Displacement: 1298cm3 (79.2 cu. in.) (DF60)

The 70 Hp = Displacement: 1502cm3 (91.6 cu. in.)

My take is that there is no detuning - just smaller capacity. Theoretically you could re-bore the block on the 60 hp and make it a 90 in simplistic terms.

That in itself wont make it more reliable or more robust. Its just a marketing ploy to "fill in the range"

Originally Posted by tom28571

I .... thought my comments were self explanatory.

Well, I didnt understand what you meant by "What the actual developed HP of these engines is".

Is "developed HP" different than just plain "HP" ?.

I understand that the HP output can be ruined by a bad prop choice, and that HP takeoff figures can be from the Prop shaft, or the Crankshaft and produce different figures. I was just trying to get a bit more explanation.

Originally Posted by tom28571

I do deal with outboards regularly and am interested in comparisons. I do trust the weights given by manufacturers but when specifying a motor of given power for a boat, need to look closely at the specs of those available to avoid space and weight problems.

Good - the more input we get, the better thre information.

[tom28571]

As far as I know, we in the US don't have any controlling entity that can enforce HP ratings as well as many other specs that we might like. I, for one, will happily do without more government intervention. There are industry standards that help to standardize such things. Mercury was once famous for under-rating their outboards. It let the Merc 10 run on lakes where HP was limited as well as making the Merc so much faster than the competition at the same "HP".

The rest is just pot stirring. No problem.

[marshmat]

I don't think there's anyone in the US actually "enforcing" hp ratings, but my understanding of the industry standards is that an engine has to be within 10% of the claimed horsepower ratings. Outboards are supposed to be rated at the prop shaft. Example- a few years ago ('99 or so), there was a Merc 90 and a Yamaha 100 that were built on the same line, the powerheads being identical in all respects. Both actually produced about 96 hp at the prop. Merc called its version a 90 because a lot of boats had a 90 hp rating, while Yamaha decided to market "a bit more power" at the same price as a 90.

[tom28571]

Originally Posted by marshmat

I don't think there's anyone in the US actually "enforcing" hp ratings, but my understanding of the industry standards is that an engine has to be within 10% of the claimed horsepower ratings. Outboards are supposed to be rated at the prop shaft. Example- a few years ago ('99 or so), there was a Merc 90 and a Yamaha 100 that were built on the same line, the powerheads being identical in all respects. Both actually produced about 96 hp at the prop. Merc called its version a 90 because a lot of boats had a 90 hp rating, while Yamaha decided to market "a bit more power" at the same price as a 90.

Matt,

My points exactly, and this filters all through the hp range and names on the decal.

[Fanie]

I will be more than happy to supply spec/data on the engines

So Wynand, what will it take to actually get the info I requested from you - I was under the impression you are a dealer

I, for one, will happily do without more government intervention.

It is no where more true than here Tom. Anything with a 15 hp motor here has to be surveyed, yearly It just about making money and nothing else.

[Jack B]

[quote=rwatson;301306]Hmm, can we not trust the facts quoted by manufacturers ? They get validated by lots of different people. I wouldnt have thought they would fib much.


Interesting little game of ping pong this.
We recently built a boat using the Cummins 425hp QSB 5.9 engine. When launched the trim was all messed up and we had to do a lot of remedial work. Eventually we ended up weighing items, including the complete boat to try and get the trim right.
The end of it all was the Cummins weight was given as 612 kg, and we verified this with them. The actual weight was 840kg with ZF box which is 72 kg. This makes their advertised weight about 20% out.
Engines of this power to weight ratio will nearly always be used in performance boats where weight is definitely an issue. In fact we would not have bought the Cummins if the correct weight had been advertised.
But in saying all that it is still a nice engine.
Our rule now is, check the weight before fitting it. They DO fib.

Jack.

[hoytedow]

Originally Posted by mwatts

No Yamaha's lower end brand is Selva. Tohatsu's are built by Nissan. I don't know if they are 1:1 the same though.

Actually, Tohatsu builds engines for Nissan.

[Wynand N]

Originally Posted by Fanie

So Wynand, what will it take to actually get the info I requested from you - I was under the impression you are a dealer

Fanie, I will do better and phone you with the info. I was so busy meeting deadlines with boat repairs/buoyancy now that summer is here again and guys wanting to get on the water, I forgot your stuff....

Anything with a 15 hp motor here has to be surveyed, yearly It just about making money and nothing else.

Actually Fanie, according to SAMSA Marine Notice 13 (latest) any engine size up to and including 15hp, are excluded from all the crap (skippers license, COF, COL) but the hull, if over 3.1 meters, must still have buoyancy fitted and the boat must carry the basic safety equipment as required in Category "R" boats.
Anything over 15hp, even a 15.5hp, you are in for the full monty so to speak

[Wynand N]

Originally Posted by tom28571

The point is that many people always assume that 4 strokes are much heavier than 2 strokes. I only point out that this is not always so.

Im with Watson on this - I still have to see a 4S of similar hp that is lighter than a 2S version....

Originally Posted by tom28571

Detuned engines are generally considered to be more reliable and rugged than their more optimized competitors.

This is true - having all the Tohatsu info at hand, I can safely say that the following engines are sisters of same cylinder capacity and tuned and de-tuned to their specific ratings. Usually the lower rated engine achieved its HP at lower RPM and some carb jetting, timing and port tuning are the main differences. The numbers below are for two stroke only.

4hp & 5hp - single cylinder - 102cc
6hp, 8hp & 9.8hp - twin cylinder - 169cc
9.9hp & 15hp - twin cylinder - 247cc
25hp & 30hp - twin cylinder - 429cc
40hp & 50hp - three cylinder - 697cc
60hp & 70hp - three cylinder - 938cc
115hp, 120hp & 140hp - four cylinders - 1768cc

[tom28571]

[quote=Wynand N;302449]Im with Watson on this - I still have to see a 4S of similar hp that is lighter than a 2S version....

A matter of reading the words. The statement was "much" heavier, not "lighter" than 4 strokes.

[rwatson]

Originally Posted by Wynand N

the following engines are sisters of same cylinder capacity and tuned and de-tuned to their specific ratings. Usually the lower rated engine achieved its HP at lower RPM and some carb jetting, timing and port tuning are the main differences.

Hi Wynand

You would have to provide the RPM/HP curve graph to convince me though.

Especially with two strokes. A cheaper, nastier exhaust will drop the HP significantly.

Actually, I dont see the 60 HP 2 stroke on sale
say at http://www.tohatsu.com.au/products.htm

are you sure they are still current ? - the 140 HP 2 stroke you quoted before is N/a

[Wynand N]

Originally Posted by rwatson

Actually, I dont see the 60 HP 2 stroke on sale
say at http://www.tohatsu.com.au/products.htm

are you sure they are still current ? - the 140 HP 2 stroke you quoted before is N/a

Watson, seems like different markets dictates different engines. Here in the land of murder, rape, corrupt government/president etc, we have no laws re emissions to adhere to, and we still have have a ball.

The Tohatsu 60hp is available from our importer and in stock. The 140hp is a hot number here and freely available - how many do you want to order from me?

As soon as I have time available, I will post you the rpm of the "sister" engines mentioned later.