Yamaha F6SMHA 6HP 15in Outboard Motor

Description

Transport crew members ashore using the Yamaha F6SMHA FourStroke Outboard Motor platform on 15-inch transoms. This single-cylinder 139cc engine generates 6 continuous brake horsepower at 5,000 RPM for light yacht tenders and auxiliary work punts. Overhead valve design delivers high fuel combustion efficiency, operating quietly on coastal bays while eliminating oily exhaust smoke without oil mixing requirements.

Constructed with a lightweight aluminum alloy block, this engine features a built-in 1.1-liter fuel tank and manual recoil starter. Dry weight measures 59 lbs on a 15-inch shaft. The internal wet sump holds 0.6 quarts of marine lubricant. Raw seawater circulates through zinc-protected water jackets, with an external two-way fuel line valve allowing connections to external fuel tanks.

Key Features of Yamaha F6SMHA

Yacht owners buy Yamaha F6SMHA outboard engine models to provide dependable auxiliary propulsion for small short-transom rowboats and dinghies. The lightweight powerhead combines clean four-stroke operation with built-in fuel tank convenience.

• Built-in 1.1-liter internal fuel tank allows convenient short trips without carrying bulky external fuel cans
• Two-way fuel valve switches between internal tank feeds and optional external fuel lines with a lever turn
• Single-cylinder 139cc OHV powerhead delivers high combustion efficiency and clean exhaust emissions
• Manual recoil starter with auto-decompression provides smooth pull-starting with minimal physical effort
• Full 360-degree tiller steering allows true reverse thrust maneuvering without complex reverse gear linkages
• Fold-down tiller handle and large carrying handles make stowing this engine inside boat lockers simple
• Engine-mounted Yamaha F6SMHA oil inspection sight glass allows instant lubricant level checks without tools
• Sacrificial zinc anodes on the anti-ventilation plate protect lower gearcase metals from saltwater galvanic attack

Combustion Profile Thermal Thresholds

Thermal control valves maintain engine operating temperatures between 125°F and 140°F across variable harbor ambient temperatures. The single-cylinder engine develops 6 horsepower, operating within a recommended full-throttle band of 4,500 to 5,500 RPM. Fuel burn records 0.45 GPH at 4,500 RPM cruising speed, expanding to 0.65 GPH at wide-open throttle. Water-cooled exhaust passages prevent powerhead casing heat buildup during slow trolling.

Transom Clearance Bracket Geometry

Designed for 15-inch transom heights, this outboard clamps to the stern board using twin manual screw clamps with locking pad eyes. The manual tilt bracket provides four pin positions to match hull trim angles. The tilt lock mechanism permits 60 degrees of upward travel, elevating the lower skeg clear of harbor bottom silt.

Shift Protocol Operational Limits

The side-mounted shift lever selects forward and neutral positions cleanly, with reverse accomplished via full 360-degree engine rotation. This auxiliary outboard is not engineered for continuous commercial towing, high-speed planing hulls, or thick marsh grass running. Scheduled preventative maintenance preserves internal engine tolerances across years of tender service.

• Inspect engine oil level through the sight glass and check water telltale stream each shift
• Change crankcase motor oil and inspect spark plug gap spacing every 100 hours
• Replace the raw water neoprene impeller and inspect external anodes every 12 months

Factory Warranty Crate Contents

Yamaha covers this auxiliary engine under a 1-Year commercial or 3-Year pleasure craft limited warranty. The cardboard shipping carton contains the 15-inch manual outboard motor, aluminum propeller, spare pull cord, tool kit, and original factory user publications.