Hello
Rams46,
iTouchMap.com puts your coordinates somewhere mid channel between the islands of Malaita and Nggele Sule; roughly along a line from Tulagi to Bina Harbour. Is there a small error in your coordinates? Or perhaps there is a small islet, near mid channel, that was the crash site, but too small to get mapped?
Do the locals have a record of that G4M crash date? Activity by the G4M type in the general area was not uncommon from mid August, 1942 onwards.
Regards,
Ken Glass