Martyn Tucker, formerly of Chester, admitted 28 further offences of indecent assault or gross indecency between 1967 and 1985.
On Tuesday, Caernarfon Crown Court heard that one of the victims was just 12 at the time.
Tucker is due be sentenced in August or September.
The court was told "statements of complaint" from new victims had been generated as a result of the publicity of the previous case in May 2014 when Tucker was jailed for 12 years.
That case involved five boys in abuse dating back 46 years, with some offences occurring in Flintshire while he was a scoutmaster in the area.
Myles Wilson, prosecuting, asked for two further cases alleging sexual activity with a child of 13 in 2008 - to which Tucker pleaded not guilty - to lie on file. Judge Niclas Parry agreed.
His lawyer Stephen Edwards said he was serving his sentence at Rye Hill prison, near Rugby, and his earliest release date was May 2020.
An ex-scoutmaster already jailed for abusing boys in the 1960s and 1970s has admitted cases involving another eight youngsters.