hier ein ganz interessanter Artikel über "power rating of outboards" gemäß ICOMIA 28-83 Vorschrift.
Zitat:
7 Manufacturing tolerance
The corrected power at rated speed of any individual marine propulsion engine or propulsion system must not deviate more than ±10% or 0.45kW, whichever is greater, from its declared power, except that for governed engines or systems of more than 100kW [134-HP] the tolerance shall be ±5%.
(End transcription of the ICOMIA 28-83.)
Commentary
For outboard motor enthusiasts, this standard clarifies several frequent questions. First, the "rated power" is to be the corrected power after careful measurements at the "rated speed" which is to be the mid-point of the full throttle range recommended (3.1.1). Thus, if a manufacturer declares the full throttle range to be 5000-5500 RPM, then the rated power should be derived from measurements made at 5250 RPM.
The "rated power" is to be measured at the propeller shaft. (3.3.1)
The "rated power" is recommended to be presented so that there is no more than a 6% difference between the rated power and the peak power which occurs in the full throttle speed range. (6.2). For example, an engine rated at 225-HP should not have more than 238.5-HP at any speed in the full throttle speed range. In general, the measured horsepower will be greater with engine speed. This means that if the full throttle speed range is chosen to be a wide range, for example 5,000 to 6,000 RPM, it is possible that the engine's peak horsepower will occur near 6,000 RPM, but the rated horsepower must be that obtained at 5,500 RPM. The difference between these two horsepower ratings is recommended to not be greater than 6%. It appears that manufacturers have some room to fiddle with the engine horsepower rating by adjusting the RPM range which they declare to be the the full throttle speed range of the engine. Rating of the engine horsepower in this way accounts for some of the claims seen in which engines of a particular brand and rating can test at significantly higher horsepower in actual field tests.
The tolerance for variations in manufacturing permits engines to deviate not more than ± 10% from the "rated power" (7.0). Thus an engine sold as a 150-HP engine could produce as much as 165-HP or as little as 135-HP due to variations in manufacturing tolerances. Note that the more restrictive tolerance mentioned (± 5%) applies only to "governed engines" (i.e., engines running under a governor) whose rated power is greater than 134-HP (100 kW). It is my understanding that outboards are ungoverened engines in the context of this standard, and thus all individual production units are permitted a ± 10% tolerance in actual propeller shaft horsepower compared to "rated power."
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das Ganze ist auch nur
ein Auszug von da
kurz gesagt funktioniert das bei Aussenbordmotoren also so, dass sie ganz legal mehr oder weniger als die angegebene Leistung haben dürfen, solange sie innerhalb einer +-10% Toleranzgrenze bleiben.
Recommended, also empfohlen, ist, dass zw. "rated power" und "peak power" (also Spitzenleistung) nicht mehr als 6% liegen, erlaubt sind aber max. 10%.
Beispiel: ein ETEC 150HO ist vom Hersteller mit einer Vollastdrehzahl zw. 4850 und 5850 angegeben. Die "rated power" wird also beim Mittelwert davon, also bei 5350 genommen und beträgt 150 PS.
das heisst aber nicht, dass der Motor bei 5700 auch nur 150 PS hat, sondern bis zu 165 PS haben darf, was ja angeblich auch der Fall sein soll.
So ist auch der vom Hersteller empfohlene Vollastbereich von 5500-5600 verständlich, weil der Motor wahrscheinlich die volle Leistung erst bei 5600 erreicht.
"propped" man ihn also zu steil, sodass der Motor z.B. nur 5300 max. Drehzahl erreicht, so verschenkt man 15PS und wahrscheinlich auch Vmax und schöpft nicht das ganze Potential des Motors aus,
Das selbe gilt natürlich für alle AB, was aber nicht heisst, dass auch wirklich alle AB mehr PS haben, als angegeben. Die 10% Regel ist ja auch nach unten erlaubt. Es kann aber auch sein, dass ein 150er (irgendeiner) "nur" 140 PS rated power hat und die 150 dann eben auch erst etliche Umdrehungen höher realisiert.