Something like this?

$_ = '1 2=3 4=5';
for my $up_to_3 (/(?:\W*\w+){1,3}/g) {
  print $up_to_3, "\n";
}
[download]

Update: oh, you want each grouping to start with a \w, and end with an equal sign and the number following it.

$_ = '1 2 3 2 6=7 2=4 j=384923 34 43 j 3=6';
for my $foo (/(?:\w[^=]*=\w+)/g) {
  print $foo, "\n";
}
[download]