Problem with Escape charactor

Dear Friends,

I am working with Postgres 7.3.4 on RH Linux 7.2 . I am executing a dynamic query inside a PL/pgSQL procedure and I am having the following problem.

While a line in the PL/pgSQL function is like the following
EXECUTE 'update "WATS".action_plan_master set rec_deleted_flag = 'Y' WHERE action_plan_id IN ('|| p_action_plan_ids || ')';
I got the following error.
ERROR: parser: parse error at or near "Y" at character 68

While
EXECUTE 'update "WATS".action_plan_master set rec_deleted_flag = '|| 'Y' ||' WHERE action_plan_id IN ('|| p_action_plan_ids || ')';
Error is
ERROR: Attribute "y" not found

While
EXECUTE 'update "WATS".action_plan_master set rec_deleted_flag = '|| \'Y\' ||' WHERE action_plan_id IN ('|| p_action_plan_ids || ')';
Error is
WARNING: plpgsql: ERROR during compile of sp_del_met_001 near line 47
ERROR: unterminated string

How can I specify a string charactor, as the PgAdmin3 is not using double quotes for Strings. Anyone pls shed some light.

Regards
Kumar