Yamaha
Outboard Motors

Homosassa Marine
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Yamaha
Outboard Motors

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2004 HPDI Technology

"These new HPDI's have it all — reliable, dependable and fuel efficient. And the acceleration is fantastic! Yamaha, you've done it again!"

Bruce Richardson
Key West, Florida

 


Yamaha
HPDI

Conventional
DI


HPDI RELIABILITY

Only Yamaha HPDI outboards feature unique internal-opening injectors, creating superior fuel atomization for improved performance and durability. In competitive DI outboards, the fuel injectors protrude into the combustion chamber, disrupting the fuel flow and creating the potential for carbon buildup that could reduce performance and cause potential engine malfunction.

Only Yamaha HPDI outboards feature a unique lower piston ring that optimizes the flow of oil to the upper piston ring, for unmatched reliability.

Yamaha HPDI outboards use normal spark plugs. Other DI outboards require hotter-running spark plugs that are more expensive and can be prone to pre-ignition problems.

HPDI INNOVATION
Yamaha starts the new millennium with a new dimension in marine fuel injection: High Pressure Direct Injection (HPDI). Yamaha HPDI Outboards are not redesigned automotive engines. We developed a system exclusively suited to the demanding requirements of marine outboards.


How HPDI works.
Eight sophisticated engine block sensors relay vital engine operating data to the Yamaha microcomputer, which instantly optimizes ignition timing and fuel mixture. The fuel is drawn to the fuel pump, routed through the vapor separator, and then pressurized by the high speed fuel pump to an incredible 700 psi. The injectors distribute the finely atomized fuel into the cylinders, above the pistons. Yamaha's exclusive 02 sensor continuously measures the oxygen present in the exhaust gases, enabling the computer to deliver the precise fuel mixture to each cylinder at all times. HPDI technology is just a hint of things to come, as Yamaha takes outboard technology into the new century.

PRESSURE PROVIDES INSTANT STARTS AND PRESSURE REGULATOR maintain injection pressure at a constant 700 psi.

700 PSI HIGH PRESSURE FUEL PUMP creates greater atomization of fuel for improved combustion.

INTERNAL OPENING FUEL INJECTORS do not protrude into combustion chamber. Nothing obstructs the fuel flow.

COMBUSTION CHAMBER designed to be fuel efficient at all rpm ranges, especially 2500-5500 rpm range where fuel economy is really important.

PATENTED O2 SENSOR enables microcomputer to control the air/fuel mixture and operating temperature on a per cylinder basis.

NEW 76-DEGREE BLOCK DESIGN — new narrower design provides more power.

Tomorrow's outboard fuel injection system is a reality today. Yamaha's HPDI meet the Federal EPA emissions standards for 2006 — reducing emissions by 75% — while providing the performance and fuel economy you need. It's uniquely designed to deliver fuel economy at all rpm ranges, especially the 2500-5500 rpm range, where you really need it. And not only does it do all this better, it does it as much as 4.5 decibels quieter.

700 PSI High Pressure Fuel Pump

 Back To Home Page
Accessories  |  Parts & Service Who We Are
Century Boats  |  Cobia Boats  |  Sylvan Boats
& Johnson Outboard Motors  |  Yamaha Outboard Motors
Order Parts or Accessories