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Yanmar Gearbox

KMH41A

Lighter-duty sibling of the KMH40A, an 8-degree down-angle hydraulic gear rated at 316 Nm with 1.24 to 2.62:1 ratios, standard on the 4BY3-150/180.

The KMH41A shares the KMH40A's housing and 29.5 kg dry weight but is rated at 316 Nm input. Yanmar's operation manual lists ratios of 1.24, 1.53, 2.04, 2.45 and 2.62:1 and a Borg-Warner bell housing.

Yanmar's BY3 operation manual names the KMH41A as the marine gear for the 4BY3-150 and 4BY3-180, and the 4BY3 datasheet pictures the 4BY3-180 with it, quoting ratios of 1.53, 2.04, 2.45 and 2.62:1 and a weight of 34 kg excluding foot and cooler.

Sources

  1. 1. KMH40A-KMH51A Marine Gear Operation Manual (0AKMH-EN0014, 2019.11) — Yanmar
  2. 2. BY3 Series Operation Manual (0ABY0-G00301) — Yanmar
  3. 3. 4BY3-150 / 4BY3-180 datasheet — Yanmar Europe

Specifications compiled from manufacturer sources.