Anyone know what size spanner to use on my Merc Powerhead Nuts ?

I'm about to remove ... ahem...... Try to remove ... the powerhead from my 1991 40hp 2str. 4cyl. engine. I've disconnected all the ancilliaries and have cleaned up and being WD-40'ing the hell out of the 8 x nuts for the past 48 hours. Trying desperately to avoid bolt/stud breakage. The only thing is I'm a bit unsure as to what spanner to use - I only have metric and my 10mm is too small and 11mm too loose - I guarantee it is going to round the nuts - So reckon as it's an American motor I will need to buy an imperial spanner but there doesn't seem to be much available between the 10mm and 11mm size. Is 13/32 the correct size ? Anyone know for sure ? - The Nut is officially listed as 11-64809 - NUT (5/16 IN.) at http://www.hbmmercruiserparts.co.uk/blockparts.php?ind=543&bid=140 I guess that 5/16th is referring to the thread size.

See Nuts at : http://flic.kr/p/bvY7Bv
See Engine Details at : http://flic.kr/p/bvY7Bn

Have the main thread running at http://forums.iboats.com/showthread.php?t=532276 - thought I would get an answer quicker this way.

Cheers

Re: Anyone know what size spanner to use on my Merc Powerhead Nuts ?

Dude how many places are you going to post this question? The big guys on this site do not like seeing this type of thing......

Re: Anyone know what size spanner to use on my Merc Powerhead Nuts ?

Might as well get yourself some SAE tools. 5/16" bolts typically take a 1/2" wrench. a 3/8" bolt takes a 9/16" wrench while a 1/4" bolt takes a 3/8" wrench.

There is no SAE wrench between 10 and 11 mm, 10 and 12 yes, but not 10 ans 11.

Re: Anyone know what size spanner to use on my Merc Powerhead Nuts ?

Yeah - It was a terminology thing - wasn't sure you guys were familiar with "spanners" so reposted and changed title to "wrench" wouldn't let me change title in the original post.

Re: Anyone know what size spanner to use on my Merc Powerhead Nuts ?

Cheers Don,

Will try the mole grips - the dremel and hammer and chisel - Ihave managed another 3 with my irwin damaged nut extractor socket, just the two under the front end now - how am I going to retorque these - troque wrench won't fit ?

Re: Anyone know what size spanner to use on my Merc Powerhead Nuts ?

try 7/16th