2002 merc 50hp ELPTO trigger problem?

[i-flier63]

3 cylinder 50 hp merc , top cylinder seems to be firing properly with #'s 2 and 3 miss firing and backfiring though the exhaust. compression is 118, 119, 120 respectively. Cleaned carbs and rebuilt the fuel pump. still the same. Could this be a trigger problem?
Thanks

[boats.net]

Probably need to test trigger coils.