YANMAR 4JH3-TE

Yanmar makes a 2-liter engine that is very popular. It comes in three models, naturally aspirated, turbo, and inter-cooled turbo. The first two models, having 56hp and 75hp respectively would be good choices for repowering the 424. The inter-cooled model would fit, but I think it would overpower the boat. The first model lacked the extra power that I was seeking. This might be a good choice for someone who is happy with the 54 hp provided by the W60. For my needs, the turbo-charged model would be the better choice. It was the most expensive engine of the three, but offered the most power. The engine is offered with three transmission options. All three provide gear reductions. Two of the three have the drive shaft run at a down-angle. I consider this configuration to be too difficult to adapt to the 424 engine bed. The third transmission, KBW20-1, is offered with three gear rations from 2.17 to 3.19. All three would turn the propeller too slowly for the prop I have unless I reduced the gear ration in the V-drive or changed the propeller. They also offer an SAE bell housing that would allow fitting the velvet drive. Yanmar lacks factory options for a refrigeration compressor or second alternator but there are aftermarket options available. After digging deeper, it turns out that a custom mounting platform must be fabricated in order to mount engine options. Yanmar calls this a "common bed." There are no off-the-shelf mounts that can be ordered that support both options. There are aftermarket brackets for compressors and optional high-output alternators of up to 80A available from Balmar.