YANMAR 6LPA-STP - 315hp
These engines contain many high performance features sure to appeal to the serious motorboater. The overhead cam design develops max hp at higher revs, allowing smaller, smoother running propellers. The camshaft is belt driven, reducing weight, number of parts, gear wear and noise.

The STP model even features 4 valves per cylinder for enhanced breathing and top end performance. A waste-gated water-cooled turbo really makes things happen when the throttle is put down hard. To reduce embarrassing black smoke in these times, the 6LP series engines have boost-compensated distributor-type fuel
pumps. Burn efficiency has been improved as well.

Two stage springs on fuel injectors reduce injection noise. Ladder- frame, full block- width crankshaft bearing cap structure reduces lower block area distortion and fights bearing slap. And of course belt drive makes for big cuts in timing gear noise, while the 12 balance-weight crankshaft and rubber engine mounts soak up much of the usual diesel vibration.
The STP gets you a "go fast package" of bigger oil cooler, gallery cooled pistons and big breathing 4-valve head.