Engine Coupler Wears Out

Repeated failure of the engine coupler is not normal. Lack of lubrication and poor engine alignment are the 2 main causes.
Lube the coupler regularly, as often as every 50 hours with severe usage. Newer engines allow you to do this without pulling the drive as there are grease fittings on the coupler itself. Older packages require you to remove the drive. Mercury has a special grease for this use.
In any case, the drive should be pulled at least every 100 hours to grease the u joints (new Alphas have perma-lubed u joints, no greasing required) and check the engine alignment and gimbal bearing.
A special tool is required for the  alignment check. Proper engine alignment will make the boat run smoother and reduce u joint and coupler wear. The gimbal bearing should turn smoothly, no roughness is allowed.
Alignment should be checked even on new boats, as the engine can move around a little in the first few hours of operation.

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