Seized Outboard Bracket clamp screw

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NorthRising

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Hi,

Have a 8HP outboard with a seized clamp screw. I've tried placeing a 10mm spanner on and belting it with lump hammer, spanner fractured screw won't move. I've tried a wrench and all my strength/ weight and tried the hammer on the wrench. Can't shift it. Tried WD40. Can't make it shift.

The other screw is obviously original and turns freely this is a newer replacement and seems seized. Any ideas?

James
 
'this is a newer replacement and seems seized.'

who replaced it ?

was it the correct thread?

you may have to put some heat on the bracet but that may be difficult,you also must be careful because the bracket is likly to be aluminum.
 
Try pouring boiling water over it. Assuming the screw is steel and the O/B is cast alloy, then maybe the o/b bracket may expand slightly to enable the screw to turn.
 
I agree with the heat suggestions.
Try boiling water first then, progressively hotter with a hot air gun and a flame as a last resort but remembering that aluminium melts at about 660C.(The alloy used may be quite a bit less) Try cooling the screw with wet rag while heating the bracket.
 
agree with vic, done many of these now and if the boiling water doesnt work then its the blowtorch method but you will loose the paint.
Lubricate with 2 stroke oil afterwards.

steve
 
WD40 is often used as a penetrating oil, it isn't, it's a water dispersant with very limited lubrication performance. I soaked mine in Penetrating oil, applied the hot air gun, tightened the screw, then loosened it. Even with clean, wirebrished threads, I had to repeat the performance a couple of times to free the screw off completely. I lubricated it with teflon waterproof grease and it's been good for two years now.
 
I have used a pencil flame blowtorch for this. I think its good to get the heat in quickly where needed, before anything else get heated.
Obvious precautions, make sure no stray petrol around etc.
I suppose a steamer might be safer, but I think a blowtorch is Ok with care and common sense.
Arrange the motor so you can get the flame in the right place without going near the carb etc.
Maybe put a wet towel over anything you don't want to get hot.
Heat the alloy and drip plus gas, 3in1, red diesel, on the thread.
The oil will smoke, but it should undo. wind in and out with lots of oil to remove crud, then clean up.
I favour putting copper grease on the threads for prevention, also motorbike aerosol chain wax penetrates well and doesn't drip off. I don't know that i'd buy it specially but its useful if you happen to have a bike!
 
hi
rub a bar of soap on the ali part first,when the soap turns brown heat no more or it will weaken the casting,i would not use freezing spray as it could crack if if it is die-cast ali,try brake fluid while it is warm
 
Okay some nice suggestions, I've already tried tightening first that didn't budge it either way. I'll go for subtle heat and work up to the more intense options. [No idea who fitted it, it came with the boat and was found to be seized in survey - otherwise a good engine - only now getting round to sorting out]

Thanks for the suggestions I'll let you know how I get on.

J
 
I give in taking it to a boat yard to get them to free it off, tried heat up from heat gun to flame to no avail. Also manged to knock motor over in the process -cracking the casising and who knows what other damage. Also tried to free off a balkes style seacock with heat gain to no avail, simpler frankly to buy a new one. Thanks though for all the suggetsions I know they were intended in the best of spirits.
 
Update: took it to the yard and they can't shift it either, it now getting sent away to be drilled out and most likely have a heli-coil inserted to form a new thread - expensive but as the bracket ain't made anymore I have no choice.
 
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