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V8 4.6L Mercury 200-300 Power Gains
Model
Stage 1 · 91 oct
Stage 2 · 93 oct
200 Pro XS, SeaPro200 hp stock
290hp+90hp
340hp+140hp
⚠ Requires throttle body upgrade
225 Pro XS, SeaPro225 hp stock
290hp+65hp
340hp+115hp
⚠ Requires throttle body upgrade
250 Pro XS, SeaPro, FourStroke250 hp stock
300hp+50hp
340hp+90hp
300 Pro XS, SeaPro, FourStroke300 hp stock
340hp+40hp
340hp+40hp
Let That V8 Loose
Fastboards Performance Tuning for Mercury V8 Outboards
Tampa Marine Tuning now offers Fastboards Marine Technologies performance software for 200-300hp Mercury V8 models, across FourStroke, Pro XS, and SeaPro. Depending on your engine, you're looking at an advertised gain of 50 to 140 horsepower, with real improvement in hole shot, top speed, and cruising efficiency.
More Power Needs Better Fuel
The more power you unlock, the less margin you have for cutting corners. Stage 1 needs 91 octane minimum. Stage 2 needs 93. That's the requirement, not a recommendation.
You bought a Mercury because it's the fastest engine on the water. Tuning it for more power means the fuel side of the equation matters just as much as the tune itself. Run lower octane than what's specified and you're risking real engine damage.
Premium fuel is part of the deal here. Budget for it the same way you'd budget for the tune.
Pick Your Stage Before You Order
Stage 1 and Stage 2 aren't a toggle you flip later. Each one is a specific calibration flashed to your ECU at the time of purchase, matched to the fuel it's built for. If you order Stage 1 and decide down the road you want Stage 2, that means we're reflashing the ECU. Know what you're after, confirm your octane availability, and order the stage that matches your plan.
200hp and 225hp Owners: One More Step
To hit full Stage 2 numbers, the 200 and 225 need a custom made upgraded throttle body kit. It's a real install, best left to an experienced marine mechanic. Call us for more information.
⚠️ Fuel Requirements
STAGE 1: Minimum 91 (R+M/2) / 95 RON octane.
STAGE 2: Minimum 93 (R+M/2) / 98 RON octane.
Running below these minimums will damage your engine. Stick to your service intervals.
Quick Questions
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1. Will I need a new prop?
1. Will I need a new prop?
Prop selection varies with hull design, weight, and operator preference. Generally—if propped correctly—increases of 50hp warrant consideration for a new prop. Contact us or consult a prop expert.
2. How does it work? Timelines?
2. How does it work? Timelines?
Remote tuning customers must remove and ship their ECU to us. Timelines are completely dependent on the outgoing and inbound shipping speeds you choose. Expect a 24 hour turnaround once it reaches us.
3. Does it affect my warranty?
3. Does it affect my warranty?
Not automatically — but if your motor has a powertrain or related system failure after tuning, Mercury Marine will likely deny coverage for that specific issue.
