Broken starter bolt. Why?

[Yzhogman]

Recently purchased a 2004 Glastron with 3.0 VP. Have done a lot of work to this boat already but that is another story. Today I found a long bolt laying next to bilge pump; it had obviously broke off and after a bit of searching found that it was one of two bolts that fasten starter onto block. I hadn't touched the starter. I was able to unthread the broken bit from the top side of the through hole that this bolt goes into. So, it would now be easy enough to just replace it, however, my question is: Why would this bolt break off. Just fatigue or is it indicative of something else going on? Just being cautious.

And btw, this is my first post on this forum and I would just like to say thanks to everyone who has ever shared their knowledge on a forum. Through forums like this and just a basic level of mechanical aptitude I have managed to tackle 75+% of the work on my bikes, boat and automobiles thanks to folks like you. And it's not about the $$$ saved but the satisfaction of doing it yourself.
Thanks

 

[dennis461]

previous owner broke it and gave up looking for it. Replace it with a stainless steel bolt.

 

[gm280]

Yzhogman :welcome: to iboats. Nice you decided to join us...

After reading your post, unless you see anything that would be cause for concern, I'd say replace the bolt and even check for the proper torque if need be and happy boating. And yes, these forums do help tons of folks all the time. I never get tired reading the multitude of different issues and learning as well. JMHO!

 

[bruceb58]

previous owner broke it and gave up looking for it. Replace it with a stainless steel bolt.

Do not use stainless steel bolts for this. Not even close to being strong enough...starter bolts only and tight to spec with a torque wrench!

Many 3.0s have brackets that attach to the front of the starter to stabilize it. Does yours have one.

 

[dennis461]

No Title

I use stainless steel for almost all bolts on my motor and drive nothing broke yet, buy from boltdepot.com. Nothing is more trouble than a rusted steel bolt on a boat used in bays and ocean inlets..
My starter setup is a bit different design, as seen on left of flywheel. Many folks don't know Lefty Lucy, so they break bolts.

 

[gbeltran]

Do not use stainless steel bolts for this. Not even close to being strong enough...starter bolts only and tight to spec with a torque wrench!

Many 3.0s have brackets that attach to the front of the starter to stabilize it. Does yours have one.

I'm with Bruce on this. I love stainless for most marine stuff (except when it galls) but for a starter application I would never consider them strong enough, stainless is pretty soft. I'm not sure how a 3.0 starter mounts, if it bolts to the bellhousing I'd call it iffyat best. If it takes two bolts that go the block then no way, because the proper bolts will have a knurl on them that helps locate the starter.

(and I just fully re-read your post. You absolutely need the correct starter bolts)

 

[Yzhogman]

Ok, thanks folks. I will source the proper bolt and assume there is no underlying issue.

 

[dennis461]

Ok, thanks folks. I will source the proper bolt and assume there is no underlying issue.

Make sure the starter has the correct number of shims. Do you have a good manual?
If not shimmed properly, you will brake another bolt, regardless of type steel.
If incorrect assembly was the underlying cause, the starter will bend the bolt each time it engages.

Did you notice in the other post someone asked if you had the 'bracket'.
The thread below has all the info you need.
The second thread shows part list/drawing.

Except for the knurled part on the bolt (you may not have that on the 3.0).
An 18-8 stainless has properties near grade 5 which is about 4/5 as strong in tension as a grade 8.


http://forum.chaparralboats.com/index.php?/topic/14889-30-volvo-breaking-starter-bolts/

The following is for For: 3.0GLP-A, 3.0GLP-B, 3.0GLM-A, 3.0GLM-B, 3.0GSP-C, 3.0GSM-C

http://www.volvopentastore.com/Star...on_id.222418714--store_id.366--view_id.767655