Broken starter bolt in Mercruiser 3.0L ALpha one Engine block

[srw101]

Hi everyone, I'm new here and hope that I'm in the right place for technical questions. I as of this year own a 1995 Rinker 180 Which is powered by an I/O Mercruiser 3.0L 4 cyl.

I was boating about a week ago and stopped to let my son get on the tube and so I turned my engine off. I tried to start it but it just made a grinding noise and until yesterday I couldn't figure out why it wouldn't turn over. It appears that one of the starter bolts broke off and fell out and was sitting under the engine. This obviously allowed the starter to rotate away from the flywheel and thus wouldn't allow it to turn over. My dilemma is how to get out the broken bolt piece that is in the block. My plan was to use an EZ out or bolt extractor but I never got that far. I tried to drill it out using a left hand bit but the bit wasn't hard enough to drill the hardened bolt so that plan failed. I then decided to use a carbide bit but this apparently push the broken bolt piece father into the block. The bolt that broke is the longer of the two and its about 4 inches long.

I have two questions:

1. Can I access the other side of the broken bolt if I remove the oil pan to remove it with pliers or something?

2. If I keep drilling and it falls out the other side will it do mechanical damage or will it just fall in the pan and sit there?

Thanks for any information, I appreciate it

 

[Bt Doctur]

Re: Broken starter bolt in Mercruiser 3.0L ALpha one Engine block

1 No, 2 No. starter bolts go into the block ,no where else.worst case is pull the motor and flip it over on a stand.

 

[dingdongs]

Re: Broken starter bolt in Mercruiser 3.0L ALpha one Engine block

remove the rest of the starter and the thread of the bolt that broke will normally rotate undone with very little effort.if not a small hole about 4 to 5 mm or 1/8" to 1/4" and bang a torx bit into the hole and rotate undone.
i believe the correct replacement bolts are available off ebay if you browse.
can be done with engine still in but may need to be a contortionist.

 

[Harritwo]

Re: Broken starter bolt in Mercruiser 3.0L ALpha one Engine block

I just did this exact job on my 3.0L Merc with almost the same conditions you are describing. I used a right angle battery powered drill with a left hand twist carbide bit. First thing is to get a transfer punch and center punch the hole. Then drill with the left hand carbide bit. If it hangs up, it might back the broken remnants out, if not just drill until it is out, then chase the threads and reinstall a new starter bolt. Worst case is you might have to install a heli-coil or a king cert. I would use a king cert if possible. I did this without removing the engine, it is a slow process but i was able to accomplish it. When i reinstalled the starter, i bought new starter bolts and then i also manufactured a bracket for the rear of the starter to the engine block to remove the weight. When i can find it, I will post a picture of the bracket. There are numerous posts on this exact repair on this board. While drilling, use lots of PB Blaster or cutting oil to help your bit out. The key is the carbide left hand twist bit. McMaster -Carr sells them and i bought a Short one due to the clearance issues. Good Luck.

 

[srw101]

Re: Broken starter bolt in Mercruiser 3.0L ALpha one Engine block

1 No, 2 No. starter bolts go into the block ,no where else.worst case is pull the motor and flip it over on a stand.

So a blind hole huh? That's the info I needed man thanks a lot!

 

[derekeichelman]

Re: Broken starter bolt in Mercruiser 3.0L ALpha one Engine block

So a blind hole huh? That's the info I needed man thanks a lot!

I just finished this exact same job on my Sunbird, except I pulled the motor. Trying to get in the bilge with a drill was a nightmare. If you have an engine hoist, just take the seats out, put the hoist in the boat, pick up the engine, and pull the hoist back a few feet. I tried to pull it out over the back of the boat once and it barely cleared. Also, try to avoid "easy outs" or any kind of bolt extractor. I had one break off inside of the starter bolt and spent the entire day with the dremel trying to work around it after dulling alot of drill bits.

Good luck, it's not too hard, just use the right tools and have patience.

 

[Anton_Kor]

I did this repair with the engine in the boat. The process seems more stressful when reading, than the real work involved. Might be luck.

Tools: a mirror, flashlight, insulating tape, 90 degrees right angle battery powered drill with a left-hand spiral extractor (http://www.irwin.com/tools/screw-bolt-extractors/10-pc-spiral-extractor-drill-bit-combo-pack), friend and beer as a gift.

First thing is to center punch a hole in the base (broken end) of the bolt body. I used a `’max`’ size bit, from the above linked set, wrapped with electrical/insulating tape to the size of the hole. 3-5 minutes needed to tap the center.

Then, drill with “middle” size bit. One person holds the drill aligning to the bold axis and the second person, reaching from above the engine pulls the drill to apply the needed pressure against the bolt. 2-3 minutes and you get an inch, it’s enough for using a spiral extractor.

Pretty much, that’s it. Be careful and good luck.