Chris Bond spent a lot of seat time in the Biloxi Back Bay, driving the Bullet 20XD/225 Pro Max at WOT to find the best setup.

Editor's Note: The following is the last in a three-part series on mod- ifying a 225 Pro Max. Be aware, modifying or altering '98 and newer outboards (unless such modifications are for racing purposes only) is against the new; EPA smog laws. In addition, modifying your new out- board voids factory warranties in most instances. The modifications to this particular outboard fall into the "for racing purposes only " category and are not intended for any other application.

If you are a Mercury fan and an aficionado of tweaking outboards to get the most power you can from the factory offerings, then our little series of hot-rod modifications to the venerable 2.5L Pro Max 225 should have gotten your attention.

We started with a clean slate, pulling a late '97 block from Biloxi, Mississippi's Crown Leisure Marine's inventory, changing exhaust tuners, relieving the center section with a few well-placed exhaust holes, and installing the Brucato SVS intake.

It's a combination that the 2.5-liter seems to like. All in all, the simple modifications brought the horsepower up to a shade above 250, with a fat torque curve to match. Our findings were recorded on Land & Sea's newest DynoMite engine dyno system that we plugged into a Pentium powered laptop to save and graph the results.

Chopper props, favored by serious drag racers, were our last resort when it came to figuring out the best setup for the modified Pro Max. They worked well on the Bullet.

As Phillip Bond, Crown Leisure Marine's owner says, "The perfor- mance improvements were good considering the Pro Max comes from the Factory already modified with port work, top quality reeds/cages, and a recurved black box. Seeing dramatic performance gains from an already modified' engine is wishful thinking at best."

The changes might not have been dramatic, but we did seen early 30 extra ponies come to life, and on a fast bass boat hull like the Bullet 20XD we've been using as our test platform, we expected those to contribute significantly to the boat's overall performance and top speed.

Changing props at the ramp was a common sight during test sessions.

We were not disappointed. But getting the horsepower hooked to the water was another story.

Our initial baseline run with the stock engine on the Bullet showed a respectable 83 mph with a 0-30 time of just under six seconds. Chris Bond, driver and lead mechanic during our three-month session, used Biloxi, Mississippi's Back Bay to string out the red Bullet after each modification, while I sat beside him with Stalker radar in hand.

When the last modifications were finished, it was time to hit the water and select the perfect prop and jack plate setup to see just how much faster our Bullet had become with the changes.

Chris started with the 26 Trophy. The first pass revealed that we were way beyond its range when it came to pitch selection. The Bullet came out of the hole like a drag boat and was on the rev limiter in no time at 83. He then switched to the new PVS 27 Tempest three-blade. It worked better for top speed (85.5), but cavitated badly out of the hole--and it was still tripping the rev limiter on the top.

More props and more time on the water brought the test boat to a seemingly impenetrable wall of 86, with the best prop being a reworked OMC SRX 29 and the propshaft located a full 13/4 inch above the pad. The hot Merc was able to put every prop, no matter the pitch, to the rev limiter.

At first, we theorized that the massive air rush from the Brucato SVS system at those speeds was somehow overwhelming the black box, causing a loss in horsepower. Chris disconnected the SVS's linkage (takes one bolt) and ran the boat again with each prop. The Brucato was working fine; we lost up to four miles-per-hour in some cases and were below the 6750 rev limit with the bigger wheels. We also noticed mid-range throttle response was flat compared to when the SVS was working.

Bullet Boats' Paul Nichols (left) assists Chris Bond during jackplate/setback change at Crown Leisure Marine's shop. Setback during testing varied from 12- to 14inches, with a 12-inch hydraulic jackplate being the final choice.

Finally, after several weeks of note taking, expert advice (we even had Bullet's Paul Nichols down From their Tennessee factory to over see set-up), different setback and jack plate height combinations, and a rod locker full of different props from plain to exotic, a new combination arose.