Yamaha LF350XSA2 350HP 25″ Counter-Rotation Outboard

The Yamaha LF350XSA2 is a 350hp counter rotation outboard designed with a 25-inch shaft for multi-engine offshore boats. This 4.3-liter 60-degree V6 platform produces immense structural density through its 4256 cc displacement while maintaining an optimized dry weight of 629 lbs to maximize pure marine performance. Engineered explicitly for mid-transom configurations, the 25-inch shaft length helps support ideal propeller depth and balanced tracking across heavy-duty fiberglass hulls navigating rough open ocean waters.

The 5000 to 6000 RPM operating range should be matched to the boat, load, propeller, and intended use. The 1.75:1 gear ratio should be matched with an appropriate propeller and boat setup. under heavy loads. This Japanese-built outboard leverages advanced block harmonics to eliminate low-frequency hull vibrations during severe long-range deep-sea operations.

Technical Specifications of Yamaha LF350XSA2

- Electronic fuel injection incorporates an 81mm throttle valve to maximize volumetric efficiency across all cylinders.
- A heavy-duty 70 gross amp stator fan cooled alternator generates power to keep house battery banks charged.
- The fully integrated electric steering mechanism replaces complex hydraulic lines with electronic steering integration.
- The proprietary TotalTilt system simplifies trailing and shallow-water operation by tilting the lower unit clear of the water when used as intended.
- An extensive 7.9-liter oil sump helps support optimal thermal dissipation and continuous lubrication during hard wide-open throttle runs.
- The specialized counter-rotation gearcase balances out propeller torque to maintain tracking on multi-engine express cruisers.

VCT Valve Timing Control

Variable camshaft timing adjusts the intake valves on this 24-valve double overhead camshaft V6 to optimize total thermal efficiency. This engineering process shaves critical response lag off the powerhead while drastically improving torque delivery under severe offshore environments.

Air Induction Throttle Control

An 81mm throttle valve regulates large volumes of clean air into the intake track for total combustion cycles on 89 octane fuel. This delivery system is designed to support immediate throttle response and flawless cold starts during changing early morning coastal marine conditions.

Counter Rotating Propeller Gearcase

Oversized internal gears and a streamlined lower unit maximize hydrodynamic thrust while canceling out heavy steering pull on multi-engine alignments. This mechanics minimizes lower-unit chatter while ensuring steady propeller tracking when backing down on game fish.

Digital Power Management Setup

Digital electronic control networks integrate seamlessly with the electric steering system to handle intensive house power needs automatically. This setup safely coordinates with the stator fan cooling loop to sustain modern multifunction displays and gyro stabilizers without battery drain.

Advanced Fiberglass Hull Application

High-performance bay boats, multi-engine offshore center consoles, and sportfishing platforms from 24 to 35 feet are the target vessel application for this 25-inch outboard. The mid-length shaft delivers leverage and structural vibration dampening when driving through steep waves.

Cowling Access And Lubrication

Fast access to critical checking points is provided by a multi-piece outer cowling structure that cuts service times down significantly. Changing the internal fluid volume remains completely clean thanks to an engineered drain plug location that prevents spilling oil.Maintenance note: Follow the manufacturer’s service procedures and lubrication specifications for the engine and gearcase.