cryptic

[beanzboy]

1 valve regulating supply of fuel to engine left coming back behind the square in other modification ????t??e 8

2 beginning course used to get engine turning from whats left unexpectedly with ashphalt in it s?a???? 7

3 throw away those in play 4

4remain a heavy cable used as support s?a?

5aggregate with start of proper waste water tank s?m?

[bulliver]

4 stay

[sandyRoe]

3 cast?
4 stay
5 sump?

[sandyRoe]

2 starter

[Frank97]

1 throttle?

[Lie-in King]

1 Throttle- l(ef)t (back, behind) 'T' (square) (all in) anag 'other'
2 Starter - 'tar' (in) anag 'rest' (what's left, unexpectedly)
3 Cast
4 Stay
5 Sum-p(roper)