D-400 engine explained

D-400 series engine
Manufacturer:Outboard Marine Corporation (OMC)
Lawn-Boy
Aka:Iron Horse
Production:1954--1977
Successor:D-600
Configuration:Single-cylinder 2-stroke
Displacement:108.99cc[1]
Bore:60.325mm
Stroke:38.1mm
Block:Aluminum
Head:Aluminum
Compression:4.5:1
Fuelsystem:Float carburetor
Fueltype:Petrol
Oilsystem:16:1-32:1 pre-mixed fuel:oil mix
Coolingsystem:Air-cooled
Power:3.5hp

The D-400 series engine or the Iron Horse engine was a light-duty two-stroke engine used for powering lawnmowers produced from the 1950s to the late 1970s. D-400 engines were single-cylinder engines designed and manufactured by the Outboard Marine Corporation (OMC; Johnson and Evinrude) for Lawn-Boy[2] and Masport. The D-400 engines displaced 109 cc, generated 3.5hp of power, and operated in the range of 2400-3300 RPM.[1] [3]

Description

The engines have a distinctive rectangular cowling that has created a nickname of brick-top mowers. Another distinctive feature is the two-finger vertical recoil starter.[3] The kidney-shaped muffler and exhaust unit is mounted beneath the mowers' deck and gives the engine a small, low profile design when compared to the newer and more powerful lawnmower engines. The ignition system employs a magneto, points, and a condenser (capacitor) set-up with an unusual spark-advance system which utilised a weight on the crankshaft to adjust the spark-advance amount depending on engine speed. The sprung governor was also unusual with a throw-yoke which operated under the flywheel and was linked to the throttle. The carburetor was a float design and fed into a pair of reed valves.

In New Zealand and Australia, Masport also known in New Zealand as "Charlie Gamble" offered the D-400 engine on their Premier, Premier II, Rancher, Rotacut, and Tornado models.[4] In this Oceania market, the D-400 was called the Iron Horse engine.

Notes and References

  1. Web site: Lawn-Boy Service Manual 1950--1983. 2012-02-04. 1983. Lawn-Boy.
  2. Web site: Lawn-Boy brand history . 2012-02-04 . 2012 . dead . https://web.archive.org/web/20120213165600/http://www.lawnboy.com/about/history/index.html . 2012-02-13 .
  3. Web site: Lawn Boy Engine series. 2012-02-04. 2008.
  4. Web site: Moving Up to Masport TV (1972). 2012-02-04. 2011.