snapped bolts in lower unit--no success drilling

Tom Maslar · Aug 21, 2011

I have a 1977 25 hp Evinrude outboard with 130 in both cyls. I have replaced just about everything you can bolt onto it. The lower end cant be bolted on because of snapped bolts--they are not coming off--trust me! I want to replace the leg and lower end and need to know the years compatible. I also need steering controls

Daviet · Aug 21, 2011

Re: snapped bolts in lower unit--no success drilling

I guess that the best way to tell is to look at parts breakdown and see what is the same. Are there any of the bolts sticking out of the exhaust housing? If so maybe you can use some heat to break the bolts loose.

Afzape · Aug 21, 2011

Re: snapped bolts in lower unit--no success drilling

I remove stuck hardware from aircraft, engines, etc for part of my career. It is really hard to try to give advice on a way to remove the bolts without seeing pictures of them currently. It sounds like you tried to drill them out and haven't had any luck. Did you drill on center? The rule with a bolt is to drill all the way through it to relieve the pressure on the threads then use the largest EZ-out you can fit in it. Tap the EZ-out in slightly with a hammer then use a tap handle to turn it out. Don't give into the urge to just put an adjustable wrench on the EZ-out because the uneven pressure on it will snap it easier. But, back to the beginning...pictures say a thousands words. From there I will be able to give you better advice.

clanton · Aug 21, 2011

Re: snapped bolts in lower unit--no success drilling

You weld a nut to the broke bolt. The welding heat will loosen the threads.

soundchaser · Aug 21, 2011

Re: snapped bolts in lower unit--no success drilling

drill slow if it's a stainless bolt.

BonairII · Aug 21, 2011

Re: snapped bolts in lower unit--no success drilling

Heat the bolt...let it cool. Repeat a few times. Then PB blaster...let it soak for a day. The bolt WILL come out IMO.

noelm · Aug 21, 2011

Re: snapped bolts in lower unit--no success drilling

Last resort is the ezy out, WHEN (not if) you break it, you are then in far deeper poo than you are now, only option is heat, or careful SLOW drilling with a good drill (and operator)

Haffiman · Aug 21, 2011

Re: snapped bolts in lower unit--no success drilling

The biggest mistake most people do when drilling broken bolts are they start with too big drill bit.
Take a Dremel or similar to smoth out the broken bolt.
Then a sharp punch to make a good mark in the center.
Then start with a thin drill bit 2-3 mm and go straight through the bolt if possible.

ADK_Boater · Aug 21, 2011

Re: snapped bolts in lower unit--no success drilling

Be careful when using a thin drill bit, as they are more prone to snapping if you accidently start drilling off center, after you've made your initial hole.

BonairII · Aug 21, 2011

Re: snapped bolts in lower unit--no success drilling

I'm still a fan of cutting a slot in the broken bolt and using a large flathead screwdriver. Def use heat too.

wilde1j · Aug 22, 2011

Re: snapped bolts in lower unit--no success drilling

clanton said:
You weld a nut to the broke bolt. The welding heat will loosen the threads.

I like this approach BC it works. Actually have done this in my dad's shop.

Afzape · Aug 22, 2011

Re: snapped bolts in lower unit--no success drilling

Everyone after my comment is right too. Those are all things to try BEFORE the EZ-out. I brought up the EX-out right away because he said in the title he already started drilling. So if the heads are gone and he is already drilling there is no returning. But, if there are still heads on the bolts or some of the shank sticking above the parent metal surface try the other methods mentioned FIRST.

ADK_Boater · Aug 22, 2011

Re: snapped bolts in lower unit--no success drilling

Let us know when/how you get those bolts out.

Tom Maslar · Aug 23, 2011

Re: snapped bolts in lower unit--no success drilling

a few of the bolts are snapped recessed and will no accept welding a bolt, because of this, to the best of my knowledge. Some will

Tom Maslar · Aug 23, 2011

Re: snapped bolts in lower unit--no success drilling

I tried drilling with silver and demming left hand bits in a press at small diameters and encountered walking of the bits. These were short shank bits. I also tried cobalt but think it is too hard. Easy outs both square and knurled just plain useless. The square is the worst because they snap inside and compound the problem. I used a slow speed drill and flattened the surface and center punched it with a manual punch after using a ruler to find dead center

Tom Maslar · Aug 23, 2011

Re: snapped bolts in lower unit--no success drilling

yes some look to be workable

Tom Maslar · Aug 23, 2011

Re: snapped bolts in lower unit--no success drilling

great tip on drilling all the way through--thanks!

Tom Maslar · Aug 23, 2011

Re: snapped bolts in lower unit--no success drilling

I have a lot on my plate right now--can I e-mail them to you through this sight in a few weeks?

Tom Maslar · Aug 23, 2011

Re: snapped bolts in lower unit--no success drilling

Thanks, I like the pb blaster, it is magnetic--I did use pb blaster in my attempts

snapped bolts in lower unit--no success drilling

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