Broken head bolt. Evinrude 150 E150EXERV.

havoc_squad

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If it's an aluminum block you can weld a nut on the bolt and see if you can work it out.

Otherwise if that fails after several tries, then drilling it out to the correct depth and putting in a time-sert to repair threads.
 

tphoyt

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The welded nut option works well. The heat from welding helps loosen it up as well.
If that fails put the head back on find a section of tubbing that fits the bolt hole in the head perfectly then a drill bit that fits the tubbing perfectly and that will get you a perfectly centered hole then you can drill the rest out.
Best of luck
 

ct1762@gmail.com

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The welded nut option works well. The heat from welding helps loosen it up as well.
If that fails put the head back on find a section of tubbing that fits the bolt hole in the head perfectly then a drill bit that fits the tubbing perfectly and that will get you a perfectly centered hole then you can drill the rest out.
Best of luck
good idea never heard of that before. makes sense!
 

tphoyt

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I picked that one up from Racer.
I must give him the credit.
 

McGR

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There's several ways to skin this cat...

If it were me I'd take my Dremel and cut a slot in the bolt for a large screwdriver tip. I'd then knock off all the salty junk off around the screw. Then I'd douse it in penetrating oil and let it sit for a while. Eventually I'd use a large square shaft or bolstered screwdriver and wrench to hopefully break it free.

I this doesn't work out then I'd either use the drilling or welding method.
 

saltchuckmatt

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There's several ways to skin this cat...

If it were me I'd take my Dremel and cut a slot in the bolt for a large screwdriver tip. I'd then knock off all the salty junk off around the screw. Then I'd douse it in penetrating oil and let it sit for a while. Eventually I'd use a large square shaft or bolstered screwdriver and wrench to hopefully break it free.

I this doesn't work out then I'd either use the drilling or welding method.
Penetrating oil and a heat gun on and off for a week....

Broken bolt are a PITA!
 

Crosbyman

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Nov 5, 2006
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4,908
heat soak heat soak heat soak .....try hot vinigar to loosen the calcium/salt

start with a small centered drill then move up

patience brings joy....
 

racerone

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Dec 28, 2013
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I would make a drill jig.----Use 3/4 or 1" plate steel.----You need to make sure drill does not wander off to the side.-----
 

woodycooper

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Sep 6, 2022
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Well I spoke to the local boat yard and they seemed to think torching an aluminum block will damage it. Other guys on various forums all say otherwise. I also asked a mobile outboard mechanic who was onsite and he said heat and try to grip it with vice grips. I'm taking it to the local jack-of-all-trades-boat-guy on Monday. Each person I asked referred to him first saying "have you spoken to XXX?". He's competent and won't give up. Looks like I have several valid answers, thanks all.
 

tphoyt

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Sounds you you made a good choice.
If you don’t have the proper tools for the job things can go south pretty quick.
Personally I have had very little luck using vise grips on stainless. It’s pretty soft and 8 out 10 times it will just break off again. But one never knows it could be a lucky day.
Best
 

saltchuckmatt

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Well I spoke to the local boat yard and they seemed to think torching an aluminum block will damage it. Other guys on various forums all say otherwise. I also asked a mobile outboard mechanic who was onsite and he said heat and try to grip it with vice grips. I'm taking it to the local jack-of-all-trades-boat-guy on Monday. Each person I asked referred to him first saying "have you spoken to XXX?". He's competent and won't give up. Looks like I have several valid answers, thanks all.
In this perticular spot you want to heat the bolt and let it cool over and over again.

Letting someone more experienced do it is the right call. In the mean time getting it presoaked will save him some time.
 

woodycooper

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In this perticular spot you want to heat the bolt and let it cool over and over again.

Letting someone more experienced do it is the right call. In the mean time getting it presoaked will save him some time.
Recap: I took it to a welding shop who said they could get it out. They tried welding a nut onto it etc but it was too brittle and kept breaking. So they drilled, punched, drilled, punched and used several grinding and drilling bits. Finally got through and they decided to run a tap into the threads in case any got boogered up. Tap went in just fine and when he went to remove it the tap broke off flush with the block! He wasn't applying much torque at all ... They ended up re-drilling and tapping the hole. Took them three days since they were working on it between major jobs. Now just waiting on the new thermostat seals and I can put them back on.
 

saltchuckmatt

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Recap: I took it to a welding shop who said they could get it out. They tried welding a nut onto it etc but it was too brittle and kept breaking. So they drilled, punched, drilled, punched and used several grinding and drilling bits. Finally got through and they decided to run a tap into the threads in case any got boogered up. Tap went in just fine and when he went to remove it the tap broke off flush with the block! He wasn't applying much torque at all ... They ended up re-drilling and tapping the hole. Took them three days since they were working on it between major jobs. Now just waiting on the new thermostat seals and I can put them back on.
Ouch, I broke an easy out once and it wouldn't drill out. Total disaster.

A tap in aluminum, almost unbelievable.
 

tphoyt

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That’s a nightmare come true.
Glad they were able to drill it. That no easy job.
 

mercruiser tech

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Oct 23, 2022
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Removed the heads to unclog the passages and I broke a bolt. What are my options here?


View attachment 371400
mercury casts an alloy in all there aluminum blocks so this problem never happens as aluminum corrodes and seizes any bolt so you were lucky to have only one broken - the best way for a pro repair, grind the top of the stud (broken bolt) so its pretty flat, center punch the center , using a small center drill drill the center not all the way , using smaller drill bits drill through the stud and no further you will feel it when it drills through the stud , next get the tap drill and drill through the stud, using a countersink or larger drill bit just use it to chamfer the radius of the new hole, basically just cleaning up the top of the hole then use a 3 flute taper tap same as your head bolts use some cool tool or cutting oil to aid in tapping and just a bit at a time in and out clearing away any chips ,i say use a 3 flute as the 4 flute taps bind up and may break , i cant stress enough take your time and if you dont have a drill press drill straight not crooked, dont weld anything to the existing stud as you may get into a bigger mess, when the tap starts to tighten up back it out air blow the hole to clean out metal chips and proceed until your through and done! a pro job!!
 

mercruiser tech

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Oct 23, 2022
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just to introduce my self a fella from canada
Have been a marine technician for the last 35 years and millwright machinest semi retired as i call it as now i get all kinds of my past customers coming to my house and shop , i did not advertise it but word of mouth travels fast lol
and from my place i charge around 70 hr as the shop i retired from charged 129 hr good supplement for my pension i guess and hopefully help some folks out here thank you
 

mercruiser tech

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Oct 23, 2022
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oh one more thing i hate trying to use visegrips for any stud just make a lot more work for your self, never seize on any bolts going back in if some threads look a little white and chalky buy or borrow the tap and just clean them up air blow , I am a firm believer in the copper based never seize the silver seems to gall up when heated up a bit ........just my 2 cents and hope i can help , have serviced a lot of the e-techs the last few years I am still a little skeptical about them......too many electrical issues , had one come in i think it was a 90 hp no oil alarm but it still let him run it off the lake , problem turned out i found he had clamped the battery down on the remote oil tank line made a lot of rattle bang when i got it started back up , with a no oil alarm i think it should shut down before it self destructs , and then the spark plug indexing crazy its still a fuel injected 2 stroke
 

racerone

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Dec 28, 2013
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36,033
??----Have you used a drill press on a block that was still mounted on the boat ?----Just curious here.-----You mentioned ---" if you don't have a drill press drill straight not crooked " ----I believe.
 
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