Cutlass bearing wear on H376

[reraft]

I have a 1996 376 & wanted to ask if anyone out there can tell me if they have what i believe is premature wear on the cutlass bearing. I replaced the cutlass bearing in 2009 when we hauled to paint the boat & then a year later & approx 200 hours we hauled to get a survey on the bottom before leaving for Mexico. Play in the bearing again - the yard replaced it at no charge & checked the shaft alignment & it was perfect. Now in Mexico since 2010 & when i clean the bottom it has about 1/16 inch of play & it's been about 800 engine hours but it has had play for quite awhile. Does this seem normal or am i missing something ??
Any thoughts would be appreciated
S/V Hotel California
svhotelcal.blogspot.com

 

[RichH]

Suggestions:

Pull the shaft and check for 'run-out', galling/pits, etc. in the journal area of the shaft where it 'rides' in the bearing. Stainless steel 304 is especially subject to such development of surface irregularities, especially if the shaft/engine sits idle for long periods in cutless, etc. bearings.

Also check the integrity of your engine mounts ... as the rubber engine mount components can dimensionally deform and change 'resiliency'. This can, over time, cause the engine to sink into the mounts as they deform due to the constant weight of the engine ; thus, changing the alignment.

When you have the shaft out for visual inspection, also check for concentricity and/or 'trueness' of the 'faces' of the couplers, etc. If the coupler faces, etc. arent 'true', alignment will never be accurate.

If youve been running in 'silty' or very 'muddy' water, such can abrade a cutless quite quickly.

A 'perfect' clearance for such hydrodynamic bearing such as a cutless will be approx. 0.003 -0.005" clearance for each 1" of shafting diameter. 1/16" play is ~0.060 or about 10 times too large a clearance.