Elton’s nickname used to be “Hercules.” Since those days he has procured plenty of heavy new names: Captain Fantastic, the Bitch, Ol’ Four-Eyes and Alton Yin (via mispronunciation in the U.S.S.R.). His real name is Reginald Dwight, but Hercules still seems to fit, since the 35-year-old singer-songwriter has performed at least as many arduous labors. His current task is to save a career that was practically fried to a crisp under the spotlight of fame in the mid-’70s. He’s with David Geffen’s unsentimental new label, which reportedly sent his first version of this LP back for revisions. The result: John seems to have recovered his equilibrium and is again issuing dandy, nonchalant music. Jump Up! means to have a good time in the idiom of the West Indian isle of Monserrat, where this 12-song collection was recorded last fall and winter. Elton and his fine stable of helpers seem to have done just that. John collaborates on the tunes with old friend Bernie Taupin and newer pals Gary Osborne and Tim Rice, who was co-writer of Evita and Jesus Christ Superstar. Chris Thomas, who works with the Pretenders and the Who, produces, and Pete Townshend adds guitar on a strong cut, Ball and Chain. Elton may never recover the preeminent position he once held in the pop rock world, but like Hercules, he is strong enough to carry his own reputation.