4  Obligation to return to first base (4)

 7  Singing unaccompanied in a strange place near west coast city (1,7 alt sp)

 8  Dull sound of talking heard using dictaphone, at first (4)

10 Vehicle involved in short race over strip of land (5)

11 Hires corrupt successors (5)

12 Historic Spanish mission to Malaysia returns, in part (5)

13 Smears revolutionary endorsement on moving bus (5)

15 Epic story about regular gang wars (4)

16 Thrilling when husband leaves the circle in ruins (8)

17 Restricted part of one's heart returns extremely weak cardiac pulse (4)

18 French city engulfed in volcanic eruption (4)

 1  Poop's primary definition, according to adultman (4)

 2  Yearning to grasp viable solution - you can do this! (10)

 3  Swimming tuna is eating shelled blue sea creature (8)

 4  Dares to break up with sweethearts (5)

 5  Invoking the devil, perhaps, to find shortage in cooked Big Mac (5,5)

 6  Point at tools to cover up ink, say (6)

 9  Squid I run into, prepared in French chef's first counter (8)

11 Invisible layer coating one insider-exclusive DVD (6)

12 One support taken this way when surprised? (5)

14 Tie up delicate material (4)