Mercruiser 3.0 litre broken starter bolt starboard

walter227

Cadet
Joined
Feb 9, 2012
Messages
16
The unthinkable happened, found the short bolt laying in the bilge. Determined not pull the engine , removed the long bolt which was a grade 5 , same as the broken one. After some hours of working in the tight spot bilge, could not get the 90 degree drill perpendicular.Tried heat, easy outs, tapping a torx bit in, pb blaster, and that sucker wouldnt budge. Drilled out slightly larger careful not to disturb the threads, and began tapping, albeit a much smaller size, managed to correct the hole to its original trajectory and used 4 taps, each biting a little more than the last. Finally got the 3/8 threads in place after some tedious hours. Bought new grade 8 bolts and made up a bracket from the rear of the starter to the block, there is a bolt there in the side near the starter.Got starter torqued to 45 ftlbs , then made up the bracket and removed one of the long armature bolts, attached the bracket and so far so good. Just an fyi for anyone out there going through this, , use grade 8 bolts correct lengths vary over years, and do not even test without the bracket from the starter to the block! After every few outings, check the torque of those starter bolts ..better safe than stranded!

Good luck, Walt
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
42,583
Hear a lot about bolts breaking on 3L. You sure went thought a lot to get her fixed, pretty sure you won't have trouble after this :thumb:

Probably be a good idea for all the other 3L owners to replace the bolts to grade 8
 

Alumarine

Captain
Joined
Feb 22, 2005
Messages
3,738
Isn't it best to use proper starter type bolts with the knurled part just before where the threads start?

Agree that you always need the support bracket for the tail end.
Just made one up for my mini starter.
 

alldodge

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Staff member
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Mar 8, 2009
Messages
42,583
I don't see how knurling does anything for a bolt. to help it hold. IMO it helps you hang on to it but nothing of anything else
 

Bondo

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Staff member
Joined
Apr 17, 2002
Messages
71,090
Ayuh,.... I always buy Starter Bolts, for starters,....

The knurlin' is supposed to help align the starter,......

The latest starter bolts from Merc have extended heads, 'n are a wrench size smaller to help gettin' 'em in, 'n out,.....
 
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