Karl Monsen Elvik, 51, a former member of the Church of Jesus Christ of Latter Day Saints in Pollok, Glasgow, took pictures of the boys in various states of undress.
Monsen Elvik invited one boy to go running with him and after-wards at his house, massaged him and indecently touched him.
He invented a game where the boys would take turns sitting in a cold bath and timed them to see who could last the longest.
His crimes came to light years later when he was reported to the police.
Monsen Elvik, from Caledonian Road, Wishaw, pleaded guilty at Glasgow Sheriff Court to taking in-decent images of children.
He admitted four charges of lewd and libidinous behaviour and two charges of indecent assault dating from 1986 to 1994.
Sheriff Martin Jones QC said: "I cannot escape that you were involved in grooming young boys while you were in a position of trust."
He added that the boys "ought to have been safe" with him but were not and that his sexual behaviour escalated over the years.
Procurator fiscal depute Pauline Henderson told the court Monsen Elvik seemed to get on well with youths and with church elders and he was encouraged to take activities and classes.
He arranged sleep-overs in the church hall but these were stopped after members thought that they were inappropriate.
The court was told of eight male victims who were between 12 and 16 when the offences took place.
Years later, when he was confronted by one of his victims, he begged him not to go to the police.
The crimes were later reported anony-mously, in April 2011.
Monsen Elvik was told that after completing his sent-ence he would be supervised for nine months. He was also put on the Sex Offenders' Register.