Interesting facts on HP Ratings...

[walleyehed]

According to ICOMIA 28-83, all NON-GOVERNED engines must be within 10% of rated power on engines UNDER 100kw (about 135-140HP).<br />GOVERNED engines must be within 5% of rated power, but manufacturer has the right to specify WHAT RPM the GOVERNED engine developes it's RATED power.<br />THIS is how manufacturers get through the hole on HO-type engines....they have the right to rate the engines HP at 4500 if they wish, but these engines MUST have Rev-limiters, and no specs exist as to what RPM the rev-limiter has to be set.<br />Just thought this might answer some questions for some folks.<br />This being said, let it be known there will always be a 'Rude closing the gap from the rear...

 

[seahorse5]

Re: Interesting facts on HP Ratings...

Walleyehed,<br /><br />You are close, but you have to read the ICOMIA specs very carefully. Rev limiters are not considered governors.<br /><br />On rated rpm, an outboard motor does NOT have a governor, so it is an UNGOVERNED engine.<br /><br /><br />"3.1.1--In the case of ungoverned engines, the declared speed shall be the mid-point of the full throttle speed range recommended by the manufacturer for propeller selection."<br /><br /><br />Concerning rated power and the plus or minus 10%deviation, the ICOMIA 28-83 specs read as follows:<br /><br /><br />"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 the tolerance shall be ±5%."<br /><br /><br />Once again, an outboard is NOT a governed engine and is NOT a [propulsion] system, so the first part of the sentence applies, which is + or - 10%. It is very easy to mis-interpret these specs the way they are written.

 

[walleyehed]

Re: Interesting facts on HP Ratings...

Don't take me wrong seahorse, but if a rev-limiter is governing the engine RPM-for whatever reason, why is it considered NON-governed???<br />My second question, and with all due respect, why is an outboard NOT a propulsion unit????<br />with this being said, how do they get by with the HO's being non-listed, and give no indication of where (RPM) the HP really is measured?

 

[seahorse5]

Re: Interesting facts on HP Ratings...

No sweat, my friend. <br /><br />Rev limiter is a safety item to keep a motor from coming apart and it is designed to be effective above the normal operating range of the motor. It is not a governor to keep an engine at a certain setting.<br /><br />You being an aircraft afficianado, my old Hawk XP had the Continental IO360 with a governor to keep it at or below 195hp. With a kit I could bypass the governor and turn 2800 rpm and develop 210hp, same as Cessna Skymaster.<br /><br />According to ICOMIA, there are marine engines and marine propusion systems. We are talking engines.<br /><br />The HO's have an narrow rpm operating range and the max hp is developed in the mid part of the range from what I've been told. I don't know why they say "factory tuned for best performance" instead of a hp rating, but it's a neat marketing tool, and the HO runs similar to the XS Mercs so the hp should be close. Bombardier is really an "in your face" company now, compared to OMC's milk-toast attitude. It's refreshing and it pi$$es off the competition. Next year I'll bet we see a flurry of infomercials and comparisons from all the manufacturers.

 

[walleyehed]

Re: Interesting facts on HP Ratings...

Thanks for the clarification...<br />Skyhawk XP....good bird..better than the new Hawk SPs.<br />I hope to see more 'Rudes on the fishing trail..like to see more yammys and mercs in the back seat again..

 

[OBJ]

Re: Interesting facts on HP Ratings...

Really interesting thread folks. Thanks for posting it.<br /><br />Sounds like ya' got a "thing" for Rudes Kenny....

 

[Dhadley]

Re: Interesting facts on HP Ratings...

If you think Bomb is being "Rude" to their competition now, just wait till you see what's next.

 

[phatmanmike]

Re: Interesting facts on HP Ratings...

does this mean a motor can be a 225 HO if it has a "stated" hp rating of 225 hp at, say, 5200 rpm, but actually makes 250hp at, say,6000rpm, even though its rated as a 225 hp motor?<br />is this what i think your saying as to how they are able to have a 225 AND a 225HO??????????<br /><br /><br />is this the loophole you speak of?

 

[seahorse5]

Re: Interesting facts on HP Ratings...

Nope, there is a section that covers what you are saying and that is why also the hp rpm has to be exactly between the operating rpm. That was the old Merc trick back in the 50's and early 60's, underrating the motors.