How can I remove this stuck snapped bolt?

[Nicky]

Have you disconnected the swivel pin beside the transom clamp to drop the leg off?

 

[EF Ian]

Got it off, ended up managing to fit a dremel grinding disc down there on a flexible shaft, I cut enough of the bolt that I could break it without going in far enough to damage any sealing surfaces. The bolt is still stuck but at least it can be drilled now. There are several other snapped bolts around the block that need removed also.


Anybody got a suggestion for what drill bits to use, mine are struggling to drill the hardened metal of the bolts.

The bolt has no head ? therefore there is nothing larger than the hole, that cannot pass through the hole ? So it has to be simply corrosion.

Heat is the first normal course of action, a decent mapp gass type torch would be a starting point. Although from a corrosion point of view...maybe some decent acid might eat it a little to free things up.

Its well in there, tried heat and various liquids.

Have you disconnected the swivel pin beside the transom clamp to drop the leg off?

For now I've just left the leg on. Although it may all come apart for painting if I can get the engine all good again, which should be possible, just need 4 gaskets and some new bolts after I've finished cleaning out the coolant passages.

 

[Daviddunlop83]

Got it off, ended up managing to fit a dremel grinding disc down there on a flexible shaft, I cut enough of the bolt that I could break it without going in far enough to damage any sealing surfaces. The bolt is still stuck but at least it can be drilled now. There are several other snapped bolts around the block that need removed also.


Anybody got a suggestion for what drill bits to use, mine are struggling to drill the hardened metal of the bolts.

Its well in there, tried heat and various liquids.



For now I've just left the leg on. Although it may all come apart for painting if I can get the engine all good again, which should be possible, just need 4 gaskets and some new bolts after I've finished cleaning out the coolant passages.

A good quality HSS drill bit. Dormer or similar. A solid carbide drill would break easily if drilling by hand.

 

[Mark_C]

Have you punched the centre of the bit you're trying to drill first

 

[Apis]

An impact driver, the kind you hit with a hammer, is great if you have any more bolts to remove. Not that I work on outboards but they are a godsend for splitting motorcycle engines. Same idea... Aluminium, exposed to the elements, maybe not quite as much salt though.
Talking of salt, when you see an outboard all crusted up inside, does that mean the owner didn't flush it with muffs and fresh water, or do they just go like that anyway?

 

[impact]

A good quality HSS drill bit. Dormer or similar. A solid carbide drill would break easily if drilling by hand.

+1... patience with a good HSS is better than swearing and throwing things that comes after a broken drill half way in

 

[stevieturbo]

I'd be surprised if the bolts ere particularly hard that HSS bit wouldnt drill it. Doesnt look like the other bolts are of any real high tensile nature or need.

A carbide bit will go through hardened steel with ease though if actually needed. But they can be brittle. No matter what bit you use, drilling any broken bolt by hand is always awkward.

 

[EF Ian]

A good quality HSS drill bit. Dormer or similar. A solid carbide drill would break easily if drilling by hand.

Mine are HSS, but only Erbauer so not the best quality, they work great with most thin and soft metals but are not dealing well with the hardened steel. I think an upgrade is in order.

Have you punched the centre of the bit you're trying to drill first

Yes

An impact driver, the kind you hit with a hammer, is great if you have any more bolts to remove. Not that I work on outboards but they are a godsend for splitting motorcycle engines. Same idea... Aluminium, exposed to the elements, maybe not quite as much salt though.

Thats actually a tool I could do with buying, don't have one yet.

Talking of salt, when you see an outboard all crusted up inside, does that mean the owner didn't flush it with muffs and fresh water, or do they just go like that anyway?

Generally a 5 min flush is good to keep them clear, especially with the modern ones. I always have flushed this one since I had it but bought it old so it may have been bad already. The other problem with this being an older engine with no hose attachment and no way to attach muffs means I have to run it in a big bucket and since its a two stroke it tends to oil up the water when cold started so I don't leave it running as long as I would like.

The seal around the coolant tube from the pump had also gone a bit hard and expanded so wasn't sealing like it should, I think its not being getting enough water for a while. I didn't notice until I started doing the work on it myself.

No matter what bit you use, drilling any broken bolt by hand is always awkward.

You're not wrong.

 

[Wild Thing]

You need to split midsection and remove from saddle
Oops late to the party did not see page two, ignore above

 

[Wild Thing]

I had a Johnson 235 with exactly same issues years ago, it was impossible to bring back to life, always ran hot on one bank of the V, good luck with it, a good second hand replacement might be a cheaper, less heartache option

 

[McFall1984]

Could you try weld a nut on an try screwing it out?

 

[Apis]

Anybody got a suggestion for what drill bits to use, mine are struggling to drill the hardened metal of the bolts.

As above, any good brand HSS Presto, Dormer, etc. Forget the Chinatanium ones.

I use left hand drill bits with the drill in reverse, for this job.

 

[Nicky Glanza]

I have spent hours/days sometimes trying to get bolts out of awkward places, the time lost is not worth it so I just leave it to Peter taylor engineering on the waterloo road and he sorts it every time, usually 10-20 quid

 

[Antoin]

Could you try weld a nut on an try screwing it out?

That's always my go to method.
I'm useless at drilling the thing straight so I try to avoid it if possible.

 

[-Pete-]

Hss are okay for this sort of thing but nearly always burn up eventually and as said carbide is risky and expensive.

Cobalt drills would be the best option and will easily drill that out. Can usually pick them up in singles but may as well have a set on hand. They're what I use anytime I have a bolt etc to drill out

You can go a lot slower with cobalt too and it will still cut. Hss are dulled way easier and then you can lose the material temper and then they're fooked.