The ST/W1,2,&3 workshop manual #027-08205, states on page 51 "Provision is made for a cold start device which is screwed into the machined face above the inlet port." My ST2 has the same plugs. Associated publications are Operators Handbook ST1,2,&3.....#027-08024 and Parts List ST1,2,&3.......#027-08059. dc