Bravo 3/350 Mag coupler failure

boataholic

I have a '99 330 FV with 350 Mags and Bravo 3s.  I recently had a coupler go bad because the drive input shaft spun inside the coupler stripping the splines out of the coupler.  This was an all of a sudden event with no warning vibrations, noises, etc. The input shaft seems to be fine when checked with a micrometer against the other drive and the u-joints have no play.  The drive turns freely and smoothly by hand with no unusual noises.  What could have caused this kind of failure?  I don't want to just replace the coupler and leave the real problem undiagnosed.  I would appreciate any thoughts someone may have.

Black_Diamond

1. There is a heavy duty coupler upgrade from Mercury, use that.
2. Couplers do not last forever, but a misaligned drive or a prop strike will do it. If you are doing drive inspections annually you can sometimes know it needs replacing before it fails.