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180 SL with 4.3L mercruiser broken starter bolt in block Help!

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Hi everyone! I just joined the forum today!

Have a 93 Chaparral 180 SL with a GM/Mercruiser 4.3L V6. One of the starter mounting bolts broke off and there's a piece lodged inside the hole. There are 2 starter bolts. Unfortunately the broken piece is lodged inside the hole that ends inside of the engine block. The other starter bolt has an open ended hole...

So I'm trying to extract the broken bolt myself. I've been kind of hanging face first into the engine bay area with my feet holding onto the driver's seat. Is there anyway to get better access to the engine, perhaps underneath it so I can apply more pressure with the drill? Can the seats be removed and lay on the floor of the boat? Boat is on a trailer at the moment.

Any help and advice is greatly appreciated!

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Is the broken piece loose in the threaded hole ? If yes. Would LONG needle nose pliers allow you to twist it out ? Surgeons used Forceps ?

The threads may be bent at the beginning. Borrowing a correct sized BOTOM TAP can clean out the first damaged threads if needed. I would use a vacuum cleaner hose & tip to suck out any chips in the hole. Running the screw LOOSELY into the hole will allow rethreading the threads. Again. Vacuum the chips out & remove the piece.

Might not make it out if the threads are too dry Some light weight oil if needed.

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Hi cyclops2 thanks for replying! The broken piece of the bolt is lodged inside the hole a couple of centimeters. So there isn't a piece for me to grab and twist it out. I'm pretty sure it needs to be drilled out.

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Can you grind a VERY SHARP point on a center punch ? Use that to GENTLY strike a dimple 1/2 way between the center & the edge. DO NOT get close enough to the threads to distort them.

Gently start using the point to move the stud in a unwinding direction. You need to keep the point in a good angle to transmit forces correctly. Being upside down makes it fun. Penetrating oil into the threads helps. Sometimes it works well.

As you lose that efficient 90 degree punch angle. Start a new dimple hole again. Increase force. Nothing to lose.

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thanks cyclops2! Let me make sure I am understanding you. Use a fine tip punch to strike a dimple or hole into the broken bolt. Use the punch to sort of twist/unscrew the broken piece out? I'm not sure about the process

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My guess is that the bolt snapped because it is seized in place. So it will need to be drilled out. And as you know, hard to access.

May be time to visit a machine shop...

brick

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Good info in the thread below about removing broken bolts & tools to use. Recently my B3 prop shaft anode bolt broke off flush with hole. I got it out using heat, left-handed drill bit and a screw extractor. You'll need the ratchet adapter for the extractor bit or the Lisle sockets mentioned in the link below.

http://www.garagejournal.com/forum/showthread.php?t=62687&highlight=rennsteig+screw+extractor

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Extracting a broken bolt is not difficult - if you can get at it. The problem here is access to the broken bolt.

brick

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Most people, mechanics, DO NOT tighten the starter bolts correctly or tightly enough.

When they drop a bolt ? They buy a bolt at a local hardware store. That is usually a soft bolt.

Some boats ARE IMPOSSIBLE to replace a starter by a DIY type of person / mechanic without having the bolts shake loose later.

I replace bolts & lock washers with grease covered Grade 9. Have not had a starter come loose & hang by 1 bolt ever. NEVER USE SS hardware. The threads OFTEN stretch & DIG / GALL into the threads in the hole.

Starter bolts are pure #$^% & RUSSIAN ROULLETE when done in place. If the seat & bulkhead ( wall ) are not removed first on the very difficult starters in V drive boats

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starter on my Hurricane 2003 , 4.3 mercruiser broke off both bolts 1/2 inch up inside the holes. tried the punch, no luck. hate the idea of drilling upside down, might slip and pemanently damage the starter mount. one mechanic recommended tig-welding a rod to the bolt and spinning it out, but he's too busy.. (these bolt heads had 3 hash marks. original bolt heads were stamped 88). likely gonna have to do it myself as all the boat shops are winterizing or selling snowmobiles and want to do it in the spring.  dont want to put it away broken. any other suggestions?

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Relax ........Get your repair to be first in line during the off season.  

All of us.  Borrow a good adjustable torque ratchet . & check the torque of the starter nuts/ bolts.    Battery switch OFF.  I always grease my nuts.

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Thx for the reply!  wish I could relax about this. this is my go-to workhorse boat ( need the dependability) and I already had a bad experience this past spring. Busy shop blamed it on covid-19 labor shortage and wouldn't do work they committed to previously , recommended that I trade it in and buy a new one from them and had the nerve to low-ball me on value!. I don't get the "we're too busy" compliant. Busy is good, am I right? 

 

Edited by davidjones
here's an update on the broken starter bolts: drilled them out successfully,!

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A forum member had purchased a very clean 2007 256, with a Vortec 5.7 Merc. He had overheating and starting issues, and we walked him through a compression check. As suspected, engine was damaged and needed to come out. He and I started an e-mail exchange and he was able to successfully remove his engine with a rental hoist, and delivered it here from Fairfax Va. for evaluation. We worked together and found that two valve seats had dislodged from the head, and entered the cylinder beating the piston dome down into the ring land. As head work and lower end would have cost almost as much as a crate engine, he had a new OEM long block shipped from Michigan Motors and while we were waiting for delivery, I rebuilt the raw water pump, cool fuel module, wiring harness, throttle body, cleaned the injectors, and the like as he cleaned and painted everything else at home.  I reassembled all the accessories on to the new engine and he returned with new manifolds, belt, idlers, Blah, Blah, Blah. I test ran the engine on my stand, and made a shipping cradle for it, and he returned to Fairfax ready for an install. Keep in mind, this was his first venture into this level repair, and my point is, if your engine needs to come out it's not the end of the world. Consider it a do it yourself on steroids, and while you are in there, the bilge gets cleaned, epoxy painted, and engine gets a complete inspection and service. 

The biggest failure I see with IO engines is overheating. Run over a trash bag and you can destroy even a brand new raw water pump impeller in seconds. What you can't do is drive home. Older engines would shut down from lack of oil pressure. Coast Guard said no thank you and "limp mode" was born. Designed to allow you to get out of the channel and call for a tow. Somewhere along the line, dealers used it as a marketing tool and called it limp home mode. Those that try it, at reduced power end up replacing an engine instead of a $30 impeller. The other issue is running cast iron exhaust manifolds to failure. Once water enters the cylinder, game over as nothing good happens from there. Salt water? Pull and inspect every 5 years if you do not flush and every 7 if you do. Monitor metal loss, and be conservative as regards replacement. I find it interesting how many owners kick that can down the road until it's too late. If average time of ownership is 10 years, why extend manifold service out to 7, as you are still on the hook for cost of replacement then. Buying a used boat? Pull the manifolds and raw water pump apart before the thing hits the water. Should be that easy.   Every area is different as I pulled mine at 7 years and they looked as new, as waters here are kind to the castings. My closed loop fresh water cooling helps too as it's only the manifolds that see sea water.  W

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mmmm-boy, I would love to do this. I restore Merc. outboards (presently a 300, 58A, 500, 450 and Super Hurricane in the barn) all but the 50 and Hurricane have a boat attached! bought the 4.3  with a hope I could just maintain and drive it. That being said, iff it comes to r&r, so be it. winer is long and because of covid, isolated.

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I would start off by buying Left hand drill bits.  They are nice because occasionally the bit will catch and the bolt will spin out as you are drilling.

Snap On and others have them, they are typically shorter as well (less chance to bend as you apply force)

 

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Time for a vote on these disasterous starter bolts.

Check if any ARE LOOSE NOW !!!!!!!!

Remove 1 IF  IF it is easy to remove. Go to a place that sells grade 9 or higher nuts & bolts New washers.DO ONLY 1 bolt out & back in at a time.

You did already turn off the big battery switch ?

Buy the second starter bolt.  Yes someone  used 2 different length bolts. DIY ?  I have seen 1 bolt and 1 stud in a motor.

.When you do a final insertion of new bolts. Put a new lock washer on. Then smear grease on the threads.  Tighten the bolts in about 20 lb/ ft steps untill your TORQUE RACHET cliks off at the correct tightness.  .................. ALL  bolts are ........ALWAYS installed WITH greased threads.  LOOK IT UP.

I forgot to tell you to CAREFULLY use a correct sized tap to remove the saltwater corrosion before installing bolts.

Please do not use too much force on the tap. Gentle  In & out.

 

 

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Dont use grease on bolts you are torqueing.  The lubrication changes your torque setting.  Use Anti Seize, it is literally what it is meant for, and will not change the torque settings. 

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You are wrong . Look it up in a machinist UPDATED handbook.

Roughly speaking. A rusted clogged up thread never can pull down the bolt head to develop any clamping pressure. That is why slippery grease is specified.

I am old enough to recall ALL the different Never Seizes that were in style at 1 time.  No more. The slippery threads are what converts rotary force /  torque to clamp down pressure. Modern bolt torque charts do not specify Never / Anti Seize . 

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Go to the Fastenal site for some really conflicting lubricants & their coefficients of thread friction.  Lets all keep using anything we like.

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I’ve used Left-Hand drill bits with success. Sometimes they work great. Here’s my advice. Spray a lot of penetrating oil up into the broken bolt. I like PB Blaster. Get a 1/4 inch Left Hand drill bit. I would recommend this size bit for the 3/8 inch N.C. broken bolt piece you’re trying to remove. Do the best you can to center the drill bit on the broken bolt. Is there a way to center punch a dimple to help get the drill bit closest to center? Lastly, if the bolt was put in cross-threaded, using a Left -Hand drill bit will not work to spin it out. The threads need to be in good shape on the broken bolt for this method to work.

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11 hours ago, cyclops2 said:

You are wrong . Look it up in a machinist UPDATED handbook.

Roughly speaking. A rusted clogged up thread never can pull down the bolt head to develop any clamping pressure. That is why slippery grease is specified.

I am old enough to recall ALL the different Never Seizes that were in style at 1 time.  No more. The slippery threads are what converts rotary force /  torque to clamp down pressure. Modern bolt torque charts do not specify Never / Anti Seize . 

Nope.  Grease / lubrication is never specified for bolts that are being torqued.  If you need a way to stop corrosion use the product designed to do that, which is Never Seize.

Lots of things change over time....

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Go on the web & read about Fastenal and  the TESTED lubricants that can be used on the threads. So many are acceptable. What they did not post was about NON steel bolts nuts.

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