7. Do the contacts open when the slipper is on a point of the cam? The opening should be just sufficient to receive the thin steel gauge on the special spanner. An ordinary visiting card is of approximately the same thickness.

   If it is impossible to make the above investigation by moving the timing lever, the engine must be turned by hand sufficiently to bring the cam into suitable positions.

If the contacts do not open or do not close properly the fault is due to either:-

(i) Contact arm cracked. (iii) Contact arm slipper worn.

(ii) Contact arm not moving freely. (iv) Contacts require adjustment.

Inspecting Contact Arm

8. Does contact arm fly back freely when pulled back and released?

   If it sticks apply a spot of thin oil to the pivot N on which it rocks.

   If it still sticks remove contact arm as follows:-

To Remove Contact Arm

9. Slack off the low tension terminal F and disconnect its wire.
10. Insert a bradawl or piece of stiff wire in the niche O (Fig. 1) and prise up the contact breaker tray, at the same time lifting it by means of the low tension terminal on the other side, finally removing it complete from the distributor case.
11. Prise off the small spring catch P (Figs. 3a and 3b) above the pivot N of the contact arm.
12. Slack off the nut V (Fig. 3b) securing the insulator beneath the low tension terminal.
13. Carefully lift the contact arm off its pivot and at the same time ease the spring I and the metal contact leaf G (Fig. 4) out of their sockets on the inside of the low tension terminal block.