Volvo Penta - V8-225

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Captain's Report

Mission Statement for the Volvo Penta V8-225

The mission of the V8-225 engine is to provide boaters in the 18’-24’ (5.5 m-7.3 m) range with a catalyzed 8-cylinder 5.7 L sterndrive alternative to smaller engines on the market, particularly the 6-cylinder 4.3 L engines. By providing a lot more torque at the low-end from a package that is only slightly larger and heavier than the 4.3 L engine, the new V8-225 ensures that boaters will unquestionably have the power needed in a single engine for towing sports and hauling around a crowd. Secondarily, as noted, she should be an engine of choice for boaters in high altitudes.

Distinguishing Features

Very Low CO Emissions. According to a test done by the California Air Resources Board the engine has "…3 g/kW-hr carbon monoxide (CO) emissions over the certification E4 test cycle." California's voluntary five-star exhaust emissions standards for CO is 50 g/kW-hr.

Volvo Penta V8-225

The new Volvo Penta V8-225 catalyzed engine was designed for easy maintenance and daily fluid checks in the sometimes cramped engine rooms of boats from 18' to 24’.

Durability. Because this engine is a V8 instead of a V6, it is naturally smoother running. It has five crankshaft bearings instead of the four found on the 4.3 L engines. Further, the thermostats in the exhaust manifold keep temperatures there at 140-degrees F (60 C) thus eliminating condensation that historically rusted cast iron heads and allowed water to get ingested into the cylinders. The V8-225 will also run at lower temperatures than the V6 and other V8s, we’re told by Volvo Penta. (See below.)

Full Power at Altitude. Because the V8-225 has an engine displacement that is 1.4 L greater than the 4.3 L engine -- 32% greater -- it can deliver its max rated power even at the "high altitude" of 3,500' (1,000 m).

Higher Low-End Torque. When an operator puts the hammer down on the V8-225 the throttle is actually opened just as it would be on a 300-hp 5.7 L engine at the low-end, thus providing prodigious torque for a 225-hp engine. That aspect of the engine coupled with the DuoProp gives the boat remarkable acceleration compared to the V6. The importance of this for boaters involved in towing sports is self-evident.

Competitive Fuel Consumption at Best Cruise. Because this engine can run leaner than the V6 engines it actually can get better fuel consumption at cruising speeds in many cases. Our tests show that at a best cruise speed of 3000 rpm going 26.5 mph the engine was getting 3.95 mpg. This compares quite favorably with similar boats powered by V6 4.3 L engines.

Generally Lower Noise levels. When we check noise levels of our test boat at best cruise (3000 rpm) and compare it with other boats in class powered by 4.3 L, 5.0 L and 5.7 L engines, the V8-225 was from 1 to 3 decibels quieter in about 2/3rds of the cases. While 1 to 3 decibels does not sound like much, the scale is not linear, but rather logarithmic. One measurement, 3 decibels higher than another is actually twice as loud.


Easy Access

While there are several features of the Volvo Penta V8-225 that are noteworthy, as a professional captain I must admit that I was impressed with the fact that Volvo Penta moved all the engine check points to the front of the engine and, for the most part, up high.

Volvo Penta V8-225
Here are three easily accessible features. A) The oil fill, B) the freshwater flush connection and C) the water-separating fuel filter.

Volvo Penta V8-225

Additional access points that have been conveniently located include; A) another shot of the fuel filter, B) the automatic belt tensioner, C) the water pump, D) the serpentine belt, E) the alternator mounted up high for protection from bilge water, F) the engine oil dipstick, G) the engine oil filter, and H) the power steering fluid.

This is a major factor for someone who has been in hundreds of boats and seen engine compartment hatches that only open as little as 16” (41 cm) to accommodate a daily engine check. While my job is to take these manufacturers to task for such a blatant oversight, Volvo Penta seems to be doing its part at meeting them halfway.

By making all of the fluid checks and items that may need replacing in the front of the engine, owners can do the work themselves. And if the boat yard does the work the bills ought to be less because of the ease of access which saves time and aggravation.

Thoughtful Touches

Even though this is a completely mechanical component, Volvo Penta was not without concern for adding thoughtful features. Among them, the engine oil dipstick. Not only is the ring to pull the dipstick plastic and yellow, aiding visibility and handling, but the dipstick itself is round so that any way it is put in it will fit. Additionally, the top of the dipstick tube is threaded to quickly attach a suction hose for quick oil changes.

Volvo Penta V8-225

The top of the dipstick tube is threaded for attaching a suction line to ease oil changes.

Oil Filter. The engine oil filter is another positive feature. There are no metal components to the cartridge so it is environmentally friendly. Simply drop it off at the local recycling center where it will get compressed, to eliminate the oil, and then incinerated.

Fuse Box. Consider the fuse box. It's conveniently located on top of the engine for easy access. Spare fuses are provided and are located on the underside of the cover.

Volvo Penta V8-225

Spare fuses are located just underneath the cover to the fuse box.

Winterization. Engine drain points for winterization have also been well thought-out. They are at three low points and the plugs are twist off and easily identified by their blue color. This means that the engine can be drained without any tools.

Volvo Penta V8-225

These drain points allow for quick winterization and no tools are required to drain and flush the engine.

Self Protecting

The V8-225 does a good job of keeping itself operating at peak performance. Diagnostic sensors continually monitor the operating parameters and the ECM make adjustments as needed. For example, oxygen sensors are located at the top of the exhaust manifold both before and after the catalytic converter to ensure an optimum fuel-to-air ratio.

The exhaust manifold thermostat maintains the exhaust manifold above 140-degrees and eliminates the chance of condensation forming inside the cast aluminum manifold during extended low-speed operation. It also prevents the condensation from running back into the cast iron head and into the cylinders, possibly corroding the liners and valves.

So what? Well, so a lot! Engines without the exhaust manifold thermostat (non-catalyzed engines) run several risks beyond rust. Condensation is easily created simply by idling through coldwater. Once the condensation is generated, and the engine begins to accelerate, the risk of flowing back into the cylinders causing significant damage exists (water ingestion). With a manifold temperature remaining above 140-degrees the water from the condensation is not allowed to build up and flow back down into the engine, but is evaporated instead.

The result is a head that should last for the life of the engine, according to techs at Volvo Penta.

Volvo Penta V8-225

Corrosion is prevented with the installation of sacrificial anodes that are easily changed by the end-user.

So How Does It Perform?

We tested the Volvo Penta V8-225 in a boat with a LOA of 23'4" (7.11 m) and a beam of 8'6" (2.59 m). With an empty weight of 3,708 lbs. (1682 kgs.), 46 gallons (174 L) of fuel and two people on board we had a test weight of 4,404 lbs. (1998 kgs.).

With the V8-225 driving a DPS outdrive with a 2.14 reduction ratio turning a set of FH6 props we reached a top speed at 4870 rpm of 47.4 mph. At that speed fuel burn was 17.4 gph. Best cruise came in at 3000 rpm and 26.5 mph, where the fuel burn dropped to 6.7 gph, or 3.95 mpg. In thinking back over other tests I have done on boats with similar specs, I note that this fuel efficiency is outstanding, and it is certainly another strong point of this engine.

Volvo Penta V8-225

We tested the V8-225 in a boat with a LOA of 23'4" (7.11 m) and a beam of 8'6" (2.59 m)


Hole-shot response was exceptional. The test boat sprang to life upon hitting the throttle giving us a 3.7 second time to plane, a 0-20 time of 6.2 seconds, and a 0-30 time of 9.5 seconds. To say the acceleration was thrilling is an understatement. Even the heaviest water skier will be on top of the water in no time with this powerhouse doing the work.

Equally as impressive was the midrange response time. When hitting the throttle from cruise speed, acceleration was instantaneous and threw me into the back of my seat. When discussing this aspect of the boat with Volvo Penta techs I was told that part of this mid-range acceleration was due to the DuoProp which will virtually always out accelerate a single-prop lower unit.

Mr. Clean

Volvo Penta says that this is their "cleanest engine ever" and it has a letter from the California Air Resources Board that gives the V8-225 high praise. Pointedly, the letter said that…"Volvo Penta was able to achieve such low emissions by equipping this engine family with dual three-way catalytic converters and heated oxygen sensors, and by optimizing the engine calibration."

As is well known, the state of California has the most stringent engine emission standards on the planet. Significantly, the V8-225 has not only met but improved on those standards without harming the engine's competitive performance.

Volvo Penta V8-225

The installation and our test boat leaves plenty of room all around the engine for servicing and maintenance.


Because of the impressive low-end torque, cruising fuel-efficiency, the handy placement of daily-check items, and ease of maintenance, it's easy to see how the new V8-225 engine model will be a contender in the 18' to 24' size range.

New boat buyers who want to engage in aggressive towing sports, or ones planning to have a boat load of guests most of the time, now have a very good alternative to the V6-225, certainly, and maybe even the 5.0 L V8, rated at 270-hp.

For the same reasons, when it comes to the re-powering of boats in that size range, depending on their application, owners may well want to consider the new V8-225.