Snapped bolts on ali outboard block

[doggypaddle]

Originally Posted by jyasaki

Disclaimer: I haven't read more than first few posts. Sorry if I'm stepping on toes.

If the bolts go into the block, they'll withstand a good deal of heat. Drilling and an EZ-out after heating the block should do it (assuming they're large enough to work with.) I'd go with a heatgun, but I suppose careful application of a propane torch would work as well.

jky

Easyouts are OK as long as they dont snap off! theyre nigh on impossible to drill out even with a modified carbide tipped masonry drill and the left hand threaded ones can expand the bolt as you screw them in making it even tighter.
I had the most sucess with the snap on ones that are a hard splined shaft you wack in and turn with a special socket.

[codprawn]

I would try welding a nut to what is sticking out and see if that works.

[SPUD18]

i have been removing studs for many years and drilling then stud extractors are very awkward and like most people say if they break/and they usually do theyre a nightmare. the way i do it is- tig weld a big blob on top of stud then a washer then a nut welded to washer on outside, then i use an air hammer gun which mechanics usually have, but very carefully tighten and untighten and usually the hammer action clears the threads of corrosion and lots of penetrating oil also helps

[Searider]

Originally Posted by slimtim

I said in post one my outboard was a 4 stroke, why I said that I don't know but no one seemed to notice

Didn't want to pick you up on that Tim - sounded like you were having a bad enough day as it was!

Duncan

[The Garfish]

Originally Posted by jwalker

Tap (hit) the ends of them to shock the dross

nevver mynd tapp. wakk de fkker wiv a lummp ammer

giv de studd a libberul coetin ov nytro glisserine furst.

thenn yew cann yewse de mowle gripps too gett de fkin studd owt ov yor iyeborl


garF

[Bigmuz7]

The RibNet suspense is killing me slimtim 'ave you got em out yet?

[slimtim]

I have yet to try as I've been a bit busy trying to find myself a job. I've been soaking everything in plusgas as much as I can and will try and sort it out next week.

[slimtim]

ok tried plan A today without much success. We drilled one bolt and attempted to use an easy out with a bit of heat (not enough I don't think). Predictably the easy out snapped
This was expected but I'd thought we'd give it a go anyway.

So now we are going to try and get the last 4 bolts out without snapping them. we tried using a blow torch today but it didn't seemed to get it very hot and we couldn't get the bolt out (I didn't want to try it too hard at this stage). I think the heat is just dissipating into the block. Those who have suggested the blow torch technique, how do you get round this problem? How long should I be holding the torch there for?

If I don't have any luck, next stage is to take off the gearcase and run the engine as suggested. This, with my limited experience, I think is risky so any other advice on how long I do it for would be appreciated (Nos, you suggested doing the spit test on the exhaust plate, thats all good but where's the exhaust plate?! ...up inside the leg I'm thinking).

Looking on the brightside, I managed to get my trailer wheel spinning again and the cooling system seems to have unblocked which was the whole reason for taking this plate off in the first place

[codprawn]

I think you will just have to accept that the other 4 bolts will snap - you can't do much more damage..........

Then IF there is enough sticking up weld a nut onto the top - soak everything for a while with WD40 or similar and then try again - tighten slightly before loosening.

And good luck!!!!!!!!!!!

[Nos4r2]

Originally Posted by slimtim

where's the exhaust plate?!

It's the cover you're trying to remove


If you've got an easy-out snapped in there you need professional help to sort it out.

[slimtim]

Didn't realise it went by that name. Easy out is snapped off in there but hopefully it shouldn't have reduced my chances of being able to get the stud out with mole grips and heat (once I've got the exhaust plate off).

[Hightower]

Originally Posted by Nos4r2

It's the cover you're trying to remove


If you've got an easy-out snapped in there you need professional help to sort it out.

Sorry it's not going well!

I'm afraid to say it, but Matt is probably right.

The heat from a blowlamp isn't going to get the area hot enough and will dissipate too quickly into the heatsink (engine) to be of any good.

The weld a nut and washer could be you next step. A weld set will heat up the area much quicker than the blowlamp and will give you a nice nut on the end to get some leverage with a spanner/socket set.

If that doesn't work then it's probably drill and tap time. This will mean removing the powerhead to gain access to the bottom 4 holes.

[doggypaddle]

NOS is right you need help professional help......here come the men in white coats
the stud extractor now poses the biggest problem, if it cant be drilled out with a carbide tipped drill you may need to resort to butchering the casting with a die grinder/small chisel to get it out, then getting the hole TIG welded back up and re drilled tapped, and machined down flat.
I would take the powerhead off and take it to someone who has experience of doing this, i buggered up loads i could have saved before i got the knack for removing them. try not to snap the powerhead to leg bolts

[slimtim]

Well everyone said the best way to get them out was with mole grips and heat or welding a nut on the end and heat, which I agree with. The only way to do this however is to remove the whole plate and tackling the risky bottom bolts.

My first option was to try and remove the snapped bolts with an easy out without the need to touch the bottom bolts. It was always going to be very risky to do but I have not lost anything in trying (other than maybe the strength of the bolt being compromised by the hole, but I have a backup solution for this) as I can now go ahead and get the plate off (hopefully without snapping the other bolts) and use mole grips and a load of heat. With the plate removed I think the plusgas will work much better as I don't think it penatrated enough before.

Thanks for the advice, perhaps I'll have another update tonight.

[doggypaddle]

once you have the plate off the bolts may be a bit slacker, they may be stuck in the plate to a certain extent. It may be worth investing in a mapp gas burner it burns hotter than propane. buy a new mole grips, preferable a genuine "Vise Grips" IMHO theyr'e the only ones worth using, and given the size of the studs go for the mid size ones not the big common 10" grips, the serrations on the jaws are a bit coarse to grip an M6 stud.
dont be afraid to put a lot of heat directly into the casting where the studs go, it would take a fair bit to melt it, but dont hold the heat on for minutes and minutes!! look on the bright side, its all valuable experience.
If you still cant get them out i will give you fifty quid for it

good luck!!

[yorfuoj]

Slimtim, I had exactly the same problem, 3 times on a Tohatsu (once on the 50hp exhaust plate, like you, once on a 90hp head cover for the thermostat, bith with 6mm bolts -then on a 90TLDI on the exhaust plate, 8mm bolts ...)

I had to solve the same problem, ie the metal breaks just under the head, very bad.
I did try all the above read solution, none worked, because the bolts are very hardly blocked by the corrosion, and the metal of the bolt is not very strong - less than the corrosion !.
After removing the plate, I tapped, I soldered a nut to the remaining bit of metal, WD40 make it laugh ...

The ways I solved :

6mm bolts =
I removed the plate to have access to the remaining bolt, then I threaded down to the aluminium, as close as possible. By chance, the threaded part goes up to the head, so just to clean the filets.
I soldered (silver-brazing) together a pair of 6mm nuts to have more grip.
Then - I have a lathe - I made them "special" with a 8mm cylindrical body, by cutting down the 10mm body, just the length of the spacer plate thickness.
Then, I drilled the cover plate, spacer plate and gasket, 8mm too, where necessary, and re-assembled.
"that's all" ...


8mm bolts =
when removing the exhaust plate, 3 bolts broke ... same as above, nothing worked, so I decided to drill the remaining bit of steel.
With the lathe, I made a centering steel tool, threaded to 8x125 internally, with a small 4mm hole at the end, so I was able to screw it to the bit, and get a centered hole.
Then I drilled from 4 up to 6.8, by 0.5mm steps.
I was correctly centered, so the steel chips went out more or less easily.
Then I replaced the bolts by good ones ...taking care to use ceramic paste in every hole to avoid any future seizing.

To end, dont try exotic solutions like extractor, heat, cold, hammer, solder ... in marine engines (Tohatsu but probably other brands too), they dont work.
6mm bolts are too small to be safely drilled, so better to avoid drilling if another solution were possible

[doggypaddle]

Originally Posted by yorfuoj

6mm bolts are too small to be safely drilled, so better to avoid drilling if another solution were possible

You need glasses mate!
i have drills that start at 0.3mm and its possible to drill out an M2 stud quite sucessfully. we do it all the time in Vacuum deposition equipment with stainless bolts. you just need a dremel and a patience.
Its simple to center pop a 6mm stud and get a 2mm drill down the centre!!
you just need to take your time and wear a magnifier if your eyes are tired like mine.

[Jono]

Originally Posted by yorfuoj

....
To end, dont try exotic solutions like extractor, heat, cold, hammer, solder ... in marine engines (Tohatsu but probably other brands too), they dont work.
6mm bolts are too small to be safely drilled, so better to avoid drilling if another solution were possible

Yeah, right O.... Mr Rob? Stop bringing me those Merc engines/legs to remove the studs from... you ham-fisted fecka.. apparently it doesn't work. You just gotta love experts…

[9D280]

This is all sounding remarkably familiar...... Only difference was mine said "Yamaha" down the side of the lid & it was the thermostat housing (M6 screws).

The story of the Yam (RIP) is contained in another thread(s), but the end of itr was that I was about to buy a replacement cyl head for it, but ended up doing a deal with the yard who happened to be looking for the bottom end of a Yam 55 to repair a customer's engine.... the Merc cost me not a lot more than the Cyl head was priced.

Put another way, is it worth looking round for someone with a broken Tohatsu & then you can practice on the "dead" head for next time - or if you find a similar engne with gearbox devastation, you mix & match the bits?

[Downhilldai]

Originally Posted by 9D280

- or if you find a similar engne with gearbox devastation, you mix & match the bits?

Provided the lower unit bolts come out ok.......