Child’s toy that may set the pulse racing! (10)
I believe the answer is:
peashooter
'child's toy that may set' is the definition.
'peashooter' can be an answer for 'child's toy' (I've seen this before). I'm unsure of the rest of the definition.
'pulse racing' is the wordplay.
'pulse' becomes 'peas' (I've seen this before).
'racing' becomes 'hooter' (I am not sure about this - if you are sure you should believe this answer much more).
'peas'+'hooter'='PEASHOOTER'
'the' acts as a link.
Can you help me to learn more?
(Other definitions for peashooter that I've seen before include "Toy weapon" , "child's toy" , "Child's "gun"" , "Primitive weapon" .)