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Old 02 March 2009, 17:31   #51
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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).
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Old 02 March 2009, 20:22   #52
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Quote:
Originally Posted by Nos4r2 View Post
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.
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Old 03 March 2009, 04:27   #53
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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
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Old 03 March 2009, 06:11   #54
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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.
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Old 03 March 2009, 08:17   #55
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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!!
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Old 10 March 2009, 06:03   #56
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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
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Old 10 March 2009, 08:33   #57
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Originally Posted by yorfuoj View Post
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.
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Old 10 March 2009, 08:44   #58
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Originally Posted by yorfuoj View Post
....
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…
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Old 10 March 2009, 09:01   #59
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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?
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Old 10 March 2009, 10:03   #60
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- or if you find a similar engne with gearbox devastation, you mix & match the bits?
Provided the lower unit bolts come out ok.......
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