1978 Johnson 175, 200, 235 HP Outboard Service Manual, Page 11Get this manual
y-& 150 HP SPECIFICATIONS Model20" (508 mm) transom 150849 (Evinrude) 150TL78 (Johnson) Test wheel part no 389931 Test wheel rpm 4800 rpm Carburetor high speed orifice plug Part no;j22664 Hole size 0.045" (1.14 mm) Carburetor low speed orifice plug Part no317474 Hole size 0.027" (0.69 mm)