Cryptic crossword No 3,921

Across

1. Not entirely sound choice (4)
2. Mostly likely choose over 50% off total with skill (10)
3. Old attendant led by the old farmer (6)
4. Lobby hard to get everything (4)
5. Stellar son resembling Salt? (8)
6. Bother doctor with a complaint in the rear (4)
7. British gentleman returns to face evil in state capital (8)
8. Villain in atoning develops into a saint (10)
9. United bit of grapefruit with core of wild round fruit (4)
10. Top clue (4)
11. Disputes coming from lapsed converts (9)
12. Gym to enter running competition (4)
13. Ruler in USA desperate to import almost nothing (8)
14. Mother eating fried rice filling up while in new world (8)
15. Collected toxin without active core ingredients in needle (6)
16. Spot Oscar part way through wild night, letting off steam? (6,3)

Down

1. Embracing a soul struggling with sixth sense (8)
2. Keep quiet about taking on former student (7)
3. A record height (3)
4. Strong king rejected schooling (5)
5. Butterfly parade (7)
6. Cargo carried aloft for transfer to off-site storage (6)
7. Old gods keeled over in surprise attack (5)
8. Military transport can pick odd characters to be left behind (3)
9. Skin and bones suffer punishing run (8)
10. Plant dirt about celebrity (7)
11. Run riot and stuff gold in sack around church (7)
12. Lie about limit of Mao's involvement in Leap Forward (6)
13. Shoddy shed finally about to fall (5)
14. Rogue carrying bass opening for Led Zeppelin (5)
15. Capitalist finally out of cash (3)
16. Discovered traditional drink (5)
17. Sage is one lacking in practical experience (5)