Nitrous Express 4150 Assassin Plate Stage 6 Nitrous Kit (50-300HP) w/5lb Bottle

Nitrous Express 4150 Assassin Plate Stage 6 Nitrous Kit (50-300HP) w/5lb Bottle

Marsoni

M251S

$567.99

Get it in 3 business days with 1 day shipping. Friday, May 29

Nitrous Express 4150 Assassin Plate Stage 6 Nitrous Kit (50-300HP) w/5lb BottleAssassinate the competition with the Assassin plate system. The Assassin is the most technically advanced single stage plate ever designed. The CNC machined design integrates the nitrous and fuel discharge ports into the outer perimeter. The Assassin offers a unique perimeter spray pattern that assures perfect nitrous fuel distribution. Which in turn solves the problems commonly found on single plane manifolds, particularly small and big block Fords.

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2nd time purchasing this item. The 1st one lasted 2 years, but my boat hasn't been used a lot either. The marine mechanic who replaced it for me said it was definitely time to replace it. He said it fits and works just fine. Has good water flow. As for quality and value, I'd say decent. The price is better than an OMC OEM pump. I plan on using my boat more this year, so we'll see how it holds up. I'll get it replaced at the end of the year. Ease of installation, NOT EASY. The lower unit has to be completely removed from the outboard. Some outboard are easier than others and as old as this one is, it's probably easier than some of the newer ones. I've watched a couple of videos on YouTube on how to do it and I might try to do it myself next time. It cost $360 to have it done and that's with me supplying the pump. He said it took him about 1½hours to do the job, but I was charged for 3 hours labor. Probably what the book shows. I'd buy it again and I'll try to do the job myself.

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Reviewed in the United States on March 18, 2026