2009 mercruiser 3.0 that keeps eating starters

[Carmstrong]

I've got a 2009 mercruiser 3.0 that keeps eating starters
it originally had the factory starter on it
but broke one of the main mounting bolts
had to drill it out
replaced with new starter bolts &
installed new aftermarket starter(ARCO) that's supposed to be of good quality
2nd time around my kids ran the out-drive into something in the water so that needed to be repair, also and again another mounting bolt broke plus the starter was bad, but I figured it was just from the trama the out-drive suffered from the impact
3rd time another broken mounting bolt plus the solenoid rattled loose, the long main body starter bolts were loose and where the support bracket attaches to the main body of the starter that stud has broken off
each time we've tried to do the job right, used new components, loctite on the bolts, starter sounds ok when testing, etc...
just wondering what the root of the problem is so as we don't have to keep going through this same scenario

Are there underlying harmonic issues with this engine?

Is it a poorly engineered design?

Are the gear reduction starters problematic?
etc...

One thing I'd add is that it's a ski boat
my kids take it out
and I'd bet that they are starting & stopping it more than usual as the skiers get in & out of the water /boat
however you'd still think that if it's a well enough designed system it could take some extra punishment

Wondering if there are any others out there experienced with this sort of situation

Thanks

 

[zbnutcase]

Re: 2009 mercruiser 3.0 that keeps eating starters

Yes the Chevrolet starter mount is a really poor design, and like all inline 4 cylinders, vibration is an issue. Fabricating a front support for the starter will help a lot.

 

[EddiePetty]

Re: 2009 mercruiser 3.0 that keeps eating starters

....in addition to Nutcase's suggestion you might want to take blue impressions of the pinion gear to determine the tooth contact with the ring gear. If the pinion is too deep into the ring gear 'sumthins' gonna break. A shim may be in order between the starter and engine block.