Overrated Horsepower?

[dfrants]

I have read that most outboards produced in the 70's and early 80's were sold with higher horsepower numbers than they actually produced( i.e. the Merc 50 was actually 45hp, the 80 only 75hp), was this true with the Merc V6's also? I've found a good running 1980 Merc 175 and was curious if it actually produces 175hp?

 

[racerone]

In the early / mid 80's the motor rating was changed from power at the crankshaft to power at the prop.---So yes , an older motor had a higher number on the decals.

 

[roscoe]

I doubt that many 45 year old outboards are going to produce the hp on the decal.

Also, the NMMA hp rating specifications allow a 10% +/- deviation from the rated power.

So even a new modern engine rated at 175 hp may only be
producing 158 hp.

Your 1980 block rated motor could have been rated at 165 at the prop, minus a possible 16 for rating error = 154..

Then subtract ??? hp for any wear and tear and tuning issues.

 

[cyclops222]

Does it start every time in 1 second or less ?
Does it run smoothly at all speeds ?
You do not need to post any what ifs.