CONTINUOUSWAVE

Where on an outboard do the manufacturers rate their outboards for horsepower?

Where does the Environmental Protection Agency rate the outboards for horsepower?

If you cross check a manufacturer's rating with the EPA's rating, there is quite a difference in horsepower.

--Paul

PJMSport15MY1984 wrote:Where on an outboard do the manufacturers rate their outboards for horsepower?

Generally manufacturers rate their engine power by displaying a decal on the cowling that indicates the propeller shaft horsepower as described by some common standard. The commonly used standard is the International Council of Marine Industry Association ICOMIA 28-82.

On my Evinrude outboard engine made in 2009, there is a cowling decal that says "225" which means the manufacturer has rated the engine as a 225-HP engine. There are also two clearly visible and permanently attached metallic labels that give more data; engine power is given in kiloWatts, not horsepower.

I have an example of such a secondary labels, in this case for a model-year 2008 E-TEC 250 H.O. engine:



One purpose of the secondary labels is to provide CE Marking. CE Marking is a certification mark that indicates conformity with health, safety, and environmental protection standards for products sold within the European Economic Area (EEA).

The lower label gives the engine power as 186.4 kW, which is equal to 249.9-HP. On that particular engine, the cowling decal says "250 H.O." where "H.O." means "factory tuned for high performance." So as far as I can deduce, there is not any variance between the cowling decal rating and this metallic label rating.

The upper label on the engine gives engine emission and related information, such as:

--the EPA engine family number (8BCXM0200223)
--the type of fuel to be used (unleaded gasoline)
--the spark plug to be used (QC8WEP)
--the spark plug electrode gap distance (0.028-inch ± 0.003)
--the engine emission controls (ECM, DFI)
--the FEL or family emission limit (16.16 G/kW-hr)
--the oil to be used (TC-W3)
--the engine displacement (3441-cc)

PJMSport15MY1984 wrote:Where does the Environmental Protection Agency rate the outboards for horsepower

I do not think the EPA offers any such rating of engine power. The EPA does list (somewhere on their website and buried in a very large spreadsheet presentation) the engine data the manufacturers submit to it as evidence of compliance. But if the EPA actually provides its own ratings of power, I would have no idea where you would find that information. I have never seen any EPA test data--just the manufacturer's submitted data. The data submitted to the EPA is usually in their preferred units of measure, and for power the data is in kilowatts.

PJMSport15MY1984 wrote:If you cross check a manufacturer's rating with the EPA's rating, there is quite a difference in horsepower.

I am confused by your statement, considering that it was preceded by two questions asking where the two rating data were to be found. If you did not know where the rating data was to be found, how did you conclude that there was a variance between them?

I meant what part of the engine does the manufacturer use to rate horsepower. For example, do they measure it at the crank or the propeller?

Ratings you see on the cowls are with ±10-percent of the actual certified dyno tested output power. So in theory a 70hp motor could range from 63hp to 77hp. Evinrude Etec 225 was certified at 3 different dyno ratings, yet carried the 225 and 225H0 decals as marketed.

225 various ratings:

167.79kW - 225.01hp
178.97kW - 240.02hp
186.83kW - 250.54hp

Outboard companies certify the engine data annually with the EPA with a large amount of information on emissions, power, RPM, etc.


D-

PJMSport15MY1984 wrote:...what part of the engine does the manufacturer use to rate horsepower. For example, do they measure it at the crank or the propeller?

Your question is answered in the document I mentioned, ICOMIA 28-83. You should read the document to understand more about outboard engine power rating standards. Since about 1983 outboard engine horsepower is measured at the propeller shaft. On outboard engines made prior to c.1983 the power was usually measured at the crankshaft output.

dtmackey wrote:Ratings you see on the cowls are with ±10-percent of the actual certified dyno tested output power.

In ICOMIA 28-83 there is a much more specific procedure for determining the "rated power" and there is no tolerance of 10-percent involved. Rather than recite the standard, I encourage you to read it. You will find that determination of the rated power is not allowed to be as far as 10-percent off the actual power.

There is a MANUFACTURING TOLERANCE that permits the manufacturer's production process to produce engines whose actual output varies by as much as 10-percent from the rated power, but that allowance is only in the production process, not in the rating process. The ICOMIA standard was written in 1983. That was 35-years ago. Manufacturing of engines--especially outboard engines--was quite different then. Production output might vary by 10-percent--tolerances in mass production of outboard engines back then were not quite what they are in 2018.

Typically in today's modern manufacturing, it would be very unusual for any manufacturer to have a manufacturing process where his product output consisted of such a wide variation in characteristic as important as horsepower. I think any manufacturer who actually made engines that varied by plus or minus 10-percent in a random manner due to production tolerances would be out of business. Today's manufacturing is much more precise than that.

There is no secret any more about horsepower output--at least in the USA. Spark-ignition marine engines are regulated for exhaust emission by the EPA. The regulated level of exhaust emission is defined in quantities of emission per horsepower-hour. Perhaps this is not completely clear, and I will try to explain.

If an engine is producing, say, 100-HP, then in one hour of running at 100-HP output the engine must not produce more than a certain amount of the regulated emission products. For example, let's say there is some emission product that is to be limited to an output of 5-grams-per-horsepower-hour. A 100-HP engine would be permitted to produce 500-grams of that emission product in one hour.

As a general rule one can say that meeting the EPA emission limits requires the manufacturer to work harder in design and manufacturing than he might otherwise do. Thus we can say that making a 100-HP engine that only produces 500-grams of emission is a hard target to reach.

Consider a situation--often proposed by particular fans of particular brands--that engine Brand-A is really going to make 110-HP but for reasons of marketing or some unknown motivation, the Brand-A folks decide to rate it as a 90-HP. If the engine is a 90-HP engine, it only gets to product 450-grams of emission product. So if that engine were really a 110-HP engine, its actual emission output would be at a rate of 450-grams/110-HP-hour. That means that the engine would be meeting a much harder standard. It would be meeting 4-grams-per-horsepower-hour instead of the higher 5-grams-per-horsepower. That is a standard that is 20-percent better than required--and harder to meet.

The result of the EPA exhaust gas emission regulation of marine spark ignition engines has really been to eliminate any sort of misrepresentation in rated power labeling in modern engines. If you get an engine that says it is a 100-HP engine, you can be confident that it is not more than 100-HP. I don't think there is room in EPA emission certification for any manufacturer to "under-rate" their engines because that would put them at a disadvantage in meeting emission limits.

In the opposite direction, over-rating the engine is likely not going to work well, either. The EPA wants to see that the engine emission output is within the range allowed, and just declaring a 90-HP engine as a 110-HP engine is not going to earn the engine more emissions. The engine can only emit the regulated exhaust components based on its actual horsepower.

Further consideration to be given to influencing engine horsepower output are the following:

--the gasoline fuel
--the air temperature
--the barometric pressure
--the humidity

All of those elements need to be controlled in output power testing. All will influence the power output.

Testing for EPA certification uses a particular grade of gasoline fuel. Air temperature, barometric pressure, and humidity affect air density.

A further influence in the case of outboard engines being used to power boats is the water the boat is being used in. Use in tropical freshwater will product different boat speeds than use in arctic saltwater, due to variation in water density.

jimh wrote:Further consideration to be given to influencing engine horsepower output are the following:

--the gasoline fuel
--the air temperature
--the barometric pressure
--the humidity

All of those elements need to be controlled in output power testing. All will influence the power output.

Testing for EPA certification uses a particular grade of gasoline fuel. Air temperature, barometric pressure, and humidity affect air density.

A further influence in the case of outboard engines being used to power boats is the water the boat is being used in. Use in tropical freshwater will product different boat speeds than use in arctic saltwater, due to variation in water density.

Jim,

Gas, air temp and the other items are all assumed in testing and there are engineering calculations to adjust for this. HP ratings are not tied to testing a boat/motor combination in different latitude/longitude settings around the globe relative to boat speed on countless boats manufactured. EPA data is certified by each manufacturer to the EPA. This means each company completes the testing and then certifies their results to the EPA, any funny business and you have a problem like VW did on their TDI diesel, so in a perfect world EPA certifications are legit.

I encourage a stimulating conversation in this area as I did read over the ICOMIA 28-83 standard and scratch my head. I'm hoping with your deep industry and engineering background, you can shed some light on this and educate me.

D-

The influence of the water density is, or course, not part of EPA testing, but it will account for many differences in reported performance from boats. I see variation in performance in my own boat between running on a hot, humid day in the summer with air temperatures of 90-degrees and water temperatures above 70-degrees compared to the same engine, boat, and propeller running in late fall with water and air temperature maybe 50-degrees and low humidity. The engine makes more power in the denser air and the propeller and boat work better in the denser water.

As for EPA test data, I recall someone was tracking a particular engine over several years of test data. The engine, sold with a 90-HP rating, seemed to have various horsepower in EPA test data; for a while (2007 through 2011) the maximum power was 88.8-HP, and recently (2016) it was 82-HP. Apparently the manufacturer was making adjustments to the engine tuning to accomplish different outcomes. I don't know exactly what caused the different certification data horsepower. I can just presume that perhaps one year they were tuning for maximum output power and maybe another year decided to tune for better emission or some other characteristic.

I agree that the horsepower rating provided in the EPA test data is probably the best or truest horsepower rating you can get. But, as my example illustrated above showed, an engine with "250" on the cowling was tested for EPA certification at 249.9-HP. I think the general conclusion is that in today's engine you get the rated horsepower and no more.

I spent some time tracking down that ICOMIA 28-83 standard and publishing it. For a long time the only place you could find it in clear text was on CONTINUOUSWAVE.COM. But ICOMIA 28-83 is only a recommendation. I haven't seen any federal regulation that requires compliance with it, and I haven't seen any declarations from manufacturers they are rating their engines according to it--but that seems to be what everyone says it being done.