After not winning a series for most of April, the Mariners went 5-2 on their homestand, taking three of four from the Angels and two of three from Baltimore.
Morse's homer was the highlight on a night when the Mariners scored four times with two outs off Baltimore starter Wei-Yin Chen (2-3). Michael Saunders had three hits and scored three times, while Kendrys Morales had three RBIs, including a two-run double in the sixth inning.
Morse became the first Seattle hitter to have nine homers in the team's first 30 games since Mike Cameron in 2002. Cameron's total included a four-homer game, and Morse was slowed in April by a small fracture in the little finger on his right hand.
Seattle was hitting just .230 on the season with two outs, but scored four runs on key two-out hits. Bay got the Mariners started with a double into the left-field corner to score Morales in the first after Chen easily got the first two outs of the game.
The Mariners scored twice in the second, including the first triple in the career of slow-footed Seattle catcher Jesus. Leading off the inning, Montero hit a drive to deep left-center that Adam Jones was tracking. Jones seemed confident enough that he blew a bubble with his gum as he chased the long fly ball, but watched as the ball deflected off the edge of his glove just before he crashed hard into the wall. Montero scored on Saunders' single and Morales followed with another two-out RBI base hit for a 3-0 lead.
Morse then capped Chen's miserable night with his drive to right-center in the fourth. Chen matched the shortest start of his career, lasting just four innings, giving up five runs, eight hits and walking three.
Morales and the Mariners were not done, adding three more in the sixth. Morales hit a two-run double to center and scored on Bay's sacrifice fly. It was just the third time this season the Mariners scored more than seven runs.
Harang (1-3) was knocked around in his three previous outings, failing to pitch past the fifth in any allowing 13 earned runs in his previous two outings against Texas and the Los Angeles Angels.
That all changed against the Orioles. Getting ahead of batters, Harang took a one-hit shutout into the sixth inning. He retired 12 of the first 13 batters he faced and Matt Wieters was the only Baltimore batter to reach with a two-out double in the second.
Harang finally found trouble in the sixth, but was able to finish the inning without Seattle having to touch its bullpen. Manny Machado's double extended his hitting streak to 10 games and was Baltimore's first hit since Wieters' double. Nick Markakis then lined a 3-2 pitch back up the middle into center field to score Machado and end Harang's shutout. Jones followed with an RBI double, but Harang struck out Chris Davis to end the inning.
Machado added a solo homer in the eighth inning.
Notes: Former Baltimore 2B Roberto Alomar was announced Wednesday as this year's inductee into the Orioles Hall of Fame. Alomar played three seasons in Baltimore from 1996-98. He will be inducted in August. ... Orioles RHP Zach Clark made his major league debut when he took over for Chen in the fifth inning. Clark went 1 2-3 innings, allowing three runs and three hits. ... Seattle had double-digit hits in six of seven games during its homestand.