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USP Marine Tuning Performance Lower Unit Plug Kit

USP Marine Tuning


  • $29.99 USD
    Unit price per 
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Low water pressure issues at wide open throttle? We got your fix!

When it comes to raw outboard performance and hydrodynamics, generally speaking the less engine in the water -- the faster you are going to be. For lower units such Mercury Racing/Mercury Marine Sportmaster, Torque Master, and other aftermarket "race" nose cones -- this is common practice. This is where the lower unit performs it's best. To assist with this process, the manufacture places low water pickups solely on the nose cone. This allows for clean water entry at high speed allowing engine to maintain sufficient water pressure and cooling for the engine.

The issue is that most center consoles do not use this "race" style lower units. These  lower units, such as the Mercury Racing Sportmaster are reserved for boats that exceed 85-90MPH. Mercury Marine's HD lower unit is used on the majority of Mercury Verado outboards and is one of the strongest/reliable lower units on the water. This lower unit features a different, more robust profile with 8 low water pickups on the sides and two smaller ones on the nose. Alike the Mercury Racing Sportmaster lower unit, the HD lower unit also performs it's best at the waters edge. This position, though efficient, allows air to be sucked in from the side during high speed runs. This aeration creates a issue for low water pickup and causes frequent overheat and low water pressure alarms on your outboard engine in some cases. 

Assembled using 316 Stainless Steel, we have curated a full kit for plugging your lower unit low water pick up inlets which is extremely common for today's high performance outboard boats running the Mercury Marine 1.75 HD lower unit. Depending on your application and engine height, the plugging of lack of lower unit low water pick up holes on the side allows clean water to enter the lower pickup holes on the nose and bottom. It is common to start with plugging the top 4 holes on both sides and testing to see if pressure/temperature issues returns. Repeat process moving down if this does not fix issue. 

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