Starter bolt snapped! 91 5.0 mercruiser

chimmike

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Starter bolt snapped today, was our first water test. 3 cranks in the water and then whirring. Snapped below surface in the block...........any suggestions how I can get it out? Access is limited :(

pretty frustrated right now.
 

Don S

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Re: Starter bolt snapped! 91 5.0 mercruiser

99% of the time the engine gets pulled to get the broken bolt out.
 

chimmike

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Re: Starter bolt snapped! 91 5.0 mercruiser

That's what I was afraid of.
 

gm280

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Re: Starter bolt snapped! 91 5.0 mercruiser

Starter bolt snapped today, was our first water test. 3 cranks in the water and then whirring. Snapped below surface in the block...........any suggestions how I can get it out? Access is limited :(

pretty frustrated right now.

If you can see it and it is a straight shot, it is possible to remove. BUT, that doesn't mean it will be easy or quick either. Some times once a bolt breaks, you can remove it without drilling and/or using an easy-out. Because when it breaks it takes the stress off the remaining part. So if you can, try to turn it counter-clockwise with anything that will reach it and see if it does move at all. If not, then out comes the long shank drill bit, but only if you got a straight access to it. You could even get a drill bit extension adapter and try. Either way it is going to be a tedious effort at best... Go slowly and see if you can work it out over time... Using a good penetrating oil works wonders some times as well. A lot better then remove the entire engine to fix...if you can get to it!
 

chimmike

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Re: Starter bolt snapped! 91 5.0 mercruiser

I'm thinking with the starter out i can get a compact right angle drill in there to drill a hole for an extractor, if necessary. when i get the starter pulled i'll spray it down with deep creep and see if that helps.
 

gm280

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Re: Starter bolt snapped! 91 5.0 mercruiser

I'm thinking with the starter out i can get a compact right angle drill in there to drill a hole for an extractor, if necessary. when i get the starter pulled i'll spray it down with deep creep and see if that helps.

Let us know how it comes out...and good luck!
 

chimmike

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Re: Starter bolt snapped! 91 5.0 mercruiser

The other thing I was thinking though, use some mirrors and a compact right angle drill to drill it out and use an extractor. A compact right angle drill would fit in there no problem, and I have cobalt drill bits meant for metals as hard as stainless (though I know the bolts that came with the new starter are NOT stainless)
 

gm280

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Re: Starter bolt snapped! 91 5.0 mercruiser

The other thing I was thinking though, use some mirrors and a compact right angle drill to drill it out and use an extractor. A compact right angle drill would fit in there no problem, and I have cobalt drill bits meant for metals as hard as stainless (though I know the bolts that came with the new starter are NOT stainless)

Sounds like a plan. Just be real careful NOT to drill all the way through. Because then you stand the chance of getting drill shavings into the engine...and that is never a good idea...
 

James76

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Re: Starter bolt snapped! 91 5.0 mercruiser

I have removed bolts from engines before by grinding a drill to cut in reverse. It kind of goes against the flutes on the drill, but it works. If you are able to, grind/sharpen the drill to cut in reverse, and get a hold of a drill machine that you can put in reverse. The counter clockwise direction will be trying to turn the bolt in the correct direction for removal, and the heat generated during the initial cutting stage can help free the bolt, and hopefully the drill digs in, and winds the bolt out.
 

gm280

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Re: Starter bolt snapped! 91 5.0 mercruiser

I have removed bolts from engines before by grinding a drill to cut in reverse. It kind of goes against the flutes on the drill, but it works. If you are able to, grind/sharpen the drill to cut in reverse, and get a hold of a drill machine that you can put in reverse. The counter clockwise direction will be trying to turn the bolt in the correct direction for removal, and the heat generated during the initial cutting stage can help free the bolt, and hopefully the drill digs in, and winds the bolt out.

Again it sounds like good idea. You do know they sell reverse drill bits (or left-hand twist bits) in the stores. So you can regrind one or buy one. But I think you are capable enough to know how you want to accomplish this job... Again good luck and post your results...
 

SWD

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Re: Starter bolt snapped! 91 5.0 mercruiser

Sorry to hear about this. You have just replaced the starter....right? Sorry I have no words of advice on this one. It may require an engine pull one way or another.
 

SWD

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Re: Starter bolt snapped! 91 5.0 mercruiser

This is a bad one. Hope you get it fixed.
 

chimmike

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Re: Starter bolt snapped! 91 5.0 mercruiser

Again it sounds like good idea. You do know they sell reverse drill bits (or left-hand twist bits) in the stores. So you can regrind one or buy one. But I think you are capable enough to know how you want to accomplish this job... Again good luck and post your results...

This is similar to drilling out a small hole in the remaining bolt and using a straight extractor like this Spiral Flute Screw Extractors - 534/524 Series - Tools - IRWIN TOOLS

I'll have to look and see if any local stores sell left-hand drill bits though...that may certainly be a good option!
 

chimmike

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Re: Starter bolt snapped! 91 5.0 mercruiser

IT'S OUT!

I cut a piece off the busted bolt, welded it to my bench and drilled a straight hole through it, then used it as a guide, stuck it into the hole against the busted threaded portion and gradually drilled a hole in, then I was able to use a screw-type extractor to pull it out!

Now I'd like to source some grade 8 starter bolts! haha
 

SWD

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Re: Starter bolt snapped! 91 5.0 mercruiser

Good Job Mike! Watertest this week-end????? You should be able to find those type of bolts at any commercial hardware/fastnings store.
 
Last edited:

spdracr39

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Re: Starter bolt snapped! 91 5.0 mercruiser

IT'S OUT!

I cut a piece off the busted bolt, welded it to my bench and drilled a straight hole through it, then used it as a guide, stuck it into the hole against the busted threaded portion and gradually drilled a hole in, then I was able to use a screw-type extractor to pull it out!

Now I'd like to source some grade 8 starter bolts! haha

Awesome Job !!!!
 

chimmike

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Re: Starter bolt snapped! 91 5.0 mercruiser

Good Job Mike! Watertest this week-end????? You should be able to find those type of bolts at any commercial hardware/fastnings store.

I went to ACE locally which carries an excellent hardware selection, but the bolt is 4 3/8" long, plus they didn't have any coarse thread grade 8 bolts, so i ordered some sierra replacement bolts from iboats.

Water test Saturday barring bad weather!
 

Bondo

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Re: Starter bolt snapped! 91 5.0 mercruiser

IT'S OUT!

I cut a piece off the busted bolt, welded it to my bench and drilled a straight hole through it, then used it as a guide, stuck it into the hole against the busted threaded portion and gradually drilled a hole in, then I was able to use a screw-type extractor to pull it out!

Now I'd like to source some grade 8 starter bolts! haha

Ayuh,.... Go to yer Mercruiser Dealer, 'n get the newest, 'n Greatest starter bolts I've ever seen,...

The newest Mercruiser bolts have undersized, over-length heads on 'em, so's you can get a wrench on 'em,...
 

500dollar744ti

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Re: Starter bolt snapped! 91 5.0 mercruiser

^^^ I have a set of those and I love 'em, starter removal is much less hassle!
 

chimmike

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May 26, 2013
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141
Re: Starter bolt snapped! 91 5.0 mercruiser

Ayuh,.... Go to yer Mercruiser Dealer, 'n get the newest, 'n Greatest starter bolts I've ever seen,...

The newest Mercruiser bolts have undersized, over-length heads on 'em, so's you can get a wrench on 'em,...

Sounds like that's what I'll have to do. I did order the sierra bolts. I have no problem getting a socket on 'em to tighten fortunately. It's just a cramped area in there.
 
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