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Yanmar Gearbox

KMH40A

Kanzaki-built 8-degree down-angle hydraulic gear rated at 457 Nm, with 1.24 to 2.45:1 ratios, used by Yanmar on the 4LHA and 4BY3 engines.

The KMH40A is a down-angle (8 degree) hydraulic marine gear with forced lubrication. Yanmar's operation manual gives a maximum input torque of 457 Nm, maximum input speed of 5,500 rpm, ratios of 1.24, 1.53, 2.04 and 2.45:1 (same ahead and astern), 1.7 L of oil, a Borg-Warner or SAE #4 bell housing and a dry weight of 29.5 kg without oil cooler, damper or feet. Mechanical or electric shift and optional trolling are available.

The same manual's outline drawings show it on the 4LHA with mechanical and electric shift, and Yanmar publishes a 4BY3-180/150 x KMH40A drawing. It is still listed by Kanzaki.

Sources

  1. 1. KMH40A-KMH51A Marine Gear Operation Manual (0AKMH-EN0014, 2019.11) — Yanmar
  2. 2. KMH40A marine gear — Kanzaki Kokyukoki Mfg. Co., Ltd.
  3. 3. Kanzaki Gears product page (downloads and engine x gear drawings) — Yanmar Marine International

Specifications compiled from manufacturer sources.