Mechanical Slide Carburetors

Mechanical Slide Carburetors

1.  What circuit flows the smallest amount of fuel (give 3 names)?

·  Idle

·  Pilot

·  Slow

2.  The main effect of the idle circuit is from idle to ¼ throttle.

3. When does this circuit flow fuel?

·  All the time

4. What is the purpose of the idle air bleed passage?

·  Aids in atomization

5.  Where is the idle air bleed located on the carb?

·  Air cleaner side

6.  Is it normal for a carb to have Both air and fuel mixture screws for the idle circuit?

·  No

7.  What side of the carb would the air mixture screw be located on?

·  Air cleaner side

8. Turning the air mixture screw clockwise would richen the idle mixture.

9. What is the initial air mixture screw setting on most carbs?

·  1 ½ turns out

10.  What side of the carb would the fuel mixture screw be located?

·  Engine side

11. Turning the fuel mixture screw clockwise would lean the idle mixture.

12. What should the engine temperature be when adjusting the idle mixture screws?

·  Normal operating temperatures.

13.  What is the purpose of the idle fuel jet?

·  Meter the amount of fuel flow through the idle circuits

14.  The main effect of the idle outlet port is:

·  It flows fuel at idle

15.  Where is the idle outlet port located on mechanical slide carbs?

·  Engine side of slide

16.  The main effect of the by-pass port is:

·  Aids transition to mid-range by allowing a little more fuel just off idle.

17.  How is the slide controlled in a mechanical slide carb?

·  By the riders input on the throttle (directly)

18.  What is the purpose of the slide?

·  Vary the size of the venturi

19.  Name 3 shapes of slides:

·  Round

·  Flat

·  Radial flat

20.  What is the purpose of the slide cut-away?

·  Aids in transition from idle to mid-range

21.  The slide cutaway should face the air cleaner side of the carb.

22.  A slide cutaway of 1.0 will have a rich mixture, and a slide cutaway of 3.5 will have a lean mixture.

23.  The main effect of the midrange fuel circuit is from ¼ to ¾ throttle.

24.  The jet needle is attached to, and moves with the slide

25.  The needle jet is stationary in the body of the carb.

26.  On adjustable type jet needles (non EPA), the lowest clip position (closest to the taper) will result in the richest midrange mixture and the highest clip position (furthest from the taper) will result in the leanest midrange mixture.

27.  3 types of needle jets are:

·  Bleed

·  Primary

·  Primary bleed

28.  The main effect of the main fuel (high-speed) circuit is from ¾ to WOT throttle.

29. Where is the main jet located?

·  In series with the needle jet