Having a 4.236 in my boat I tend to read threads about them. We all have seen the 4.236 listed as having 67 or 72 or 85 or ?? Hp and I've often wondered about this.
The HP ratings that I did a quick google
search for show that they all fall on the HP curve from the "Pleasure Craft High-Speed Rating" graph.
67 HP at 2000 rpm
72 HP at 2250 rpm
84 HP at 2800 rpm
So from this I presume that the engine
regardless of the HP rating is the same and that the maximum rpm setting in the governor is what selects the rated HP. I presume that Perkins
did not use an actual different governor. Can anyone confirm this?
It makes sense to me to limit the rpm to 2000 and call it 67 HP for an engine
that is designed to run at WOT for ever in a heavy displacement
work boat. All the while setting the governor to 2800 rpm and calling it an 85 HP engine for a taxi or delivery
The engine in my boat does about 2200 rpm at wot no load and is a bit over propped so it does only 2000 rpm in gear
If there is any question here it would be can anyone confirm these presumptions? And has anyone changed the max rpm settings on their engine. I'm not planning to do so but I am curious.