Mariner Mercury 105/140 JET, Руководство по обслуживанию

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3B-26 - FUEL SYSTEMS 90-824052R3 JUNE 2002
Thermal Air Valve Circuit Description
a
51863
a - Thermal Air Valve
The thermal air valve circuit functions as an air
restrictor for the idle circuit which is controlled by a
thermal open/close valve monitoring engine
temperature. The valve is located on the starboard
cylinder head below no. 3 spark plug. When the
engine temperature is below 100
°
F (38
°
C) the
thermal air valve is closed. When a cold engine is
running, the thermal air valve restricts air to the idle
circuit causing the fuel mixture to be richer. When the
engine warms sufficiently, the thermal valve opens
allowing required fuel/air mixture for efficient
operation.
WMH Carburetor Fuel Circuit
Description
Idle Circuit Description
IMPORTANT: If welch plugs and air trim screws
must be removed for carburetor cleaning, count
number of turns air screw is turned in until
seated, then remove. Apply Loctite 271 and set
air screws to the same position (approx. 1-1/4
turns).
Top View
b a
g
f
c
d
e
50756
a - Fuel Mixture Adjustment
b - Screw Cap (two)
c - Welch Plug (two)
d - Air Trim Screw (two) - Apply Loctite 271
e - Idle Air Bleed Jet
f - Thermal Air Valve Air Inlet
g - Emulsion Tube
The idle circuit is independent of progression and
main circuits. The idle circuit consists of externally
adjustable fuel mixture screws, idle air bleed jet, and
factory set air trim screws located beneath welch
plugs.
IDLE CIRCUIT ADJUSTMENTS
a. Fuel mixture screws (2 per carb.) - When
adjusting fuel mixture screws all screws must
be turned the same amount and the same
direction for engine to operate efficiently at
idle speeds. DO NOT remove mixture screw
caps to further richen or lean fuel flow.
Clockwise direction - leans mixture
Counterclockwise direction - richens mixture
NOTE: If caps are removed from mixture screws and
screws are removed for carburetor cleaning refer to
“IMPORTANT” preceding.