Mercury 100, 150, 200, 250 (1290910 THRU 1499331) Parts & Diagrams

🔎 Mercury 100, 150, 200, 250 Reference Library — Exploded parts diagrams (16 diagrams), specifications, common issues, and maintenance checklist.

The Mercury 100, 150, 200, 250 is a 4-Stroke, Inline 4-Cylinder, EFI, SOHC outboard motor. A popular choice for small fishing boats, inflatable RIBs, and sailboat auxiliaries.

Quick Reference Specifications

Specification	Value
Engine Type	4-Stroke, Inline 4-Cylinder, EFI, SOHC
Horsepower	10 HP
Displacement	2064 cc
Bore x Stroke	90 mm x 81 mm
Spark Plug (Type & Gap)	NGK IZFR6F-11
Engine Oil Capacity	5.2 L (5.5 quart)
Recommended Engine Oil	Mercury FourStroke Oil 10W-30
Gear Case Oil Capacity	710 mL (24 fl oz)
Idle Speed (in gear)	650–700 RPM (in gear)
Full Throttle RPM Range	5000-6000
Fuel	Unleaded Gasoline, 87 Octane min.

Always verify specifications against your owner's manual for your specific serial number range.

Common Issues & Recommended Parts

Below are common maintenance scenarios for the Mercury 100, 150, 200, 250:

Water Pump / Overheating: If the tell-tale stream is weak or absent, the water pump impeller likely needs replacement. Inspect annually or every 100 hours. → Recommended: Water Pump Impeller Kit
Engine Oil / Maintenance Light: 4-stroke engines require regular oil and filter changes. Use marine-grade oil rated for your engine. Change every 100 hours or annually. → Recommended: Oil Filter, Engine Oil
Fuel Injector Issues (EFI models): Rough idle or misfires may indicate clogged fuel injectors. Use fuel stabilizer and clean injectors periodically. → Recommended: Fuel Injector, Fuel Filter
Gear Case Oil Leak: Check lower unit seals if gear oil appears milky (water contamination). Replace seals and gaskets during lower unit service. → Recommended: Lower Unit Seal Kit, Drain Plug Gaskets
Anode Corrosion: Inspect sacrificial anodes regularly, especially in saltwater. Replace when 50% depleted to protect against galvanic corrosion. → Recommended: Zinc/Aluminum Anode Kit

Parts Diagrams & OEM Part Numbers

Expand the sections below to view detailed exploded parts diagrams and find the exact OEM replacement components for your Mercury 100, 150, 200, 250.

▶.015 OVERSIZE PISTONS AND RINGS (0 parts)

▶CARBURETOR ASSEMBLY (37 parts)

Ref	OEM Part #	Part Name
1	1333-1437	CARBURETOR ASSEMBLY, COMPLETE (KA-5B)
2	1395-8673	FLOAT ASSEMBLY
3	17-20853	PIN, FLOAT LEVER PINION
4	1399-102	LEVER, FLOAT (LOWER)
5	1399-101	LEVER, FLOAT (UPPER)
6	1395-92581	INLET NEEDLE, SEAT AND GASKET
7	27-25033	GASKET, INLET SEAT
8	1395-6027	SCREW, THROTTLE STOP LEVER
9	8146791	LEVER, THROTTLE STOP
10	1399-2012	SHAFT, THROTTLE
11	24-20869	SPRING, THROTTLE SHAFT RETURN
12	1399-1463	JET, MAIN FUEL (.063)-STANDARD
13	27-28409	GASKET, MAIN FUEL JET
14	10-28405	SCREW, PLUG - MAIN FUEL JET CHANNEL
15	27-28406	GASKET, JET CHANNEL PLUG SCREW
16	1399-1912	NOZZLE, MAIN
17	10-23178	SCREW, PLUG - MAIN NOZZLE
18	24-27160	SPRING, IDLE ADJUSTMENT SCREW
19	1399-1713	SCREW, IDLE ADJUSTMENT
20	1399-99	GASKET FLOAT BOWL COVER
21	1399-1133	COVER, FLOAT BOWL
22	1399-3938	ELEMENT, FILTER
23	10-22625	SCREW, FLOAT BOWL COVER (SHORT)
24	10-25850	SCREW, FLOAT BOWL COVER (LONG)
25	27-25851	GASKET, STRAINER COVER (LARGE)
26	27-25849	GASKET, STRAINER COVER (SMALL)
27	1399-1135	COVER, STRAINER
28	27-25848	GASKET, STRAINER COVER SCREW
29	10-25822	SCREW, STRAINER COVER FASTENING
30	10-23035	SCREW AND LOCKWASHER, THROTTLE SHUTTER
31	1399-1740	SHUTTER, THROTTLE
32	1399-1828	TUBE, IDLE
33	27-23180	GASKET, IDLE TUBE
34	19-20011	WELCH PLUG, BODY CHANNEL
35	1399-1986	REPAIR PARTS KIT
36	27-757911	GASKET, CARBURETOR FLANGE
37	11-22053	NUT, CARBURETOR MOUNTING STUD

▶CARBURETOR LINKAGE (11 parts)

Ref	OEM Part #	Part Name
--	12-20533	WASHER, CHOKE LEVER STUD
1	22931A3	THROTTLE LEVER ASSEMBLY
2	23-28039	SPACER, CHOKE SHUTTER
3	28087	SHUTTER, CHOKE
4	24-20579	SPRING, CHOKE SHUTTER
5	10-28018	SCREW, CHOKE SHUTTER TO CARBURETOR (NOT AS SHOWN)
6	16-270372	STUD, CHOKE LEVER
7	13-29402	WASHER, WAVE - CHOKE LEVER STUD
8	31816	LEVER, CHOKE
9	11-826709109	NUT, CHOKE LEVER FASTENING
10	37-28990	DECAL, CHOKE - DRIVE SHAFT HOUSING

▶CLAMP AND SWIVEL BRACKET ASSEMBLY (40 parts)

Ref	OEM Part #	Part Name
1	1427-1806A6	CLAMP BRACKET ASSEMBLY
2	22477A4	THUMB SCREW ASSEMBLY
3	12-26227	WASHER, THUMB SCREW
4	16-59620	STUD, CLAMP BRACKET
5	23-59621T	SPACER, CLAMP BRACKET STUD
6	13-8M0204647	LOCKWASHER, CLAMP BRACKET STUD
7	11-22053	NUT, CLAMP BRACKET STUD
8	17-56373A2	TILT LOCK PIN ASSEMBLY
9	16-25674	STUD, CLAMP BRACKET TO SWIVEL BRACKET
10	15-25600A1	SHIM, CLAMP BRACKET STUD
11	11-8M2014641	NUT, CLAMP BRACKET STUD FASTENING
12	26558	CO-PILOT DISC
13	10-28515	SCREW, CO-PILOT DISC TO SADDLE
14	17-26540	SWIVEL PIN
15	17-26541	ROLL PIN, SWIVEL PIN TO SADDLE
16	26864	LEVER, TILT STOP
17	10-20217	SCREW, ANCHOR - TILT STOP LEVER
18	23-20216	SPACER, TILT STOP LEVER SCREW
19	10-29237	SCREW, RETAINING - LEVER TO SWIVEL BRACKET
20	15-20473A1	SHIM, RETAINING SCREW
21	11-24652	NUT, TILT STOP LEVER SCREW
22	1445-1799A2	SWIVEL BRACKET ASSEMBLY
23	25-29316	"O" RING, SWIVEL BRACKET - SWIVEL PIN
24	22-8M0169589	FITTING, GREASE - SWIVEL PIN (1/4 - 28) (SEE NOTE)
25	19-77633Q	LUBRICAP, SWIVEL BRACKET BRACKET GREASE FITTING
26	26093A2	REVERSE LOCK LEVER ASSEMBLY
27	24-28184	SPRING, REVERSE LOCK LEVER
28	28118	FORK, ACTUATING - REVERSE LOCK LEVER
29	18-26953	COTTER PIN, ACTUATING FORK TO REVERSE LOCK LEVER
30	26092	ROD, REVERSE LOCK LEVER
31	18-45882	COTTER PIN, REVERSE LOCK LEVER TO ROD
32	23-26841	BUSHING, NYLON - REVERSE LOCK LEVER ROD
33	28114	LEVER, ACTUATING - REVERSE LOCK LEVER (1/8" THICK)
34	17-22531	ROLL PIN, ACTUATING LEVER
35	28664	LINK, PUSH - UPPER SHIFT SHAFT
36	28125	PLATE, CLAMP - CO-PILOT
37	20203	DISC, FRICTION - CLAMP PLATE AND SWIVEL BRACKET
38	10-29201	SCREW, CLAMP PLATE TO SWIVEL BRACKET
39	38-31067	SERIAL PLATE
40	10-28642	SCEW, DRIVE - SERIAL PLATE TO SWIVEL BRACKET (TAPERED)

▶CRANKSHAFT AND CENTER MAIN BEARING ASSEMBLY (15 parts)

Ref	OEM Part #	Part Name
1	415-2295	CRANKSHAFT
2	30-63326T	BEARING, BALL - CRANKCASE (LOWER)
3	26-16977	OIL SEAL, CRANKCASE (LOWER)
4	23-29736	SLEEVE, PROTECTOR - CRANKSHAFT
5	25-8M0204650	"O" RING, PROTECTOR SLEEVE
6	534-3267T25	CENTER MAIN BEARING ASSEMBLY
7	17-20032	DOWEL PIN, CENTER MAIN BEARING
8	10-69026	SCREW, CENTER MAIN BEARING CLAMPING (7/8)
9	34-21293	REED, CENTER MAIN BEARING
10	34-25454	REED STOP, MAIN BEARING REED VALVES
11	34-64632	REED STOP, MAIN BEARING REED VALVES
12	10-77280	SCREW, REED STOP MOUNTING
13	11-29469	NUT, REED STOP MOUNTING SCREW
14	17-20032	DOWEL PIN, MAIN BEARING TO CYLINDER BLOCK
15	28-20094	KEY, FLYWHEEL

▶CYLINDER BLOCK AND CRANKCASE ASSEMBLY (61 parts)

Ref	OEM Part #	Part Name
1	830-1966A2	CYLINDER BLOCK AND CRANKCASE ASSEMBLY
2	16-20990	STUD, CYLINDER BLOCK TO DRIVE SHAFT HOUSING
3	16-97012	STUD, CYLINDER BLOCK TO DRIVE SHAFT HOUSING
4	16-20956	STUD, CRANKCASE TO DRIVE SHAFT HOUSING
5	16-65865	STUD, CRANKCASE TO CARBURETOR
6	17-23784	DOWEL PIN, CRANKCASE TO CYLINDER BLOCK
7	21-27146A1	CHECK VALVE ASSEMBLY, CRANKCASE
8	19-20011	WELCH PLUG, CRANKCASE CHECK VALVE
9	1123-1196A2	CRANKCASE TOP ASSEMBLY
10	30-63326T	BEARING, BALL - CRANKCASE (UPPER)
11	15-20514A1	SHIM, BALL BEARING TO CRANKCASE TOP
12	31-20594	BEARING, ROLLER - CRANKCASE (UPPER)
13	26-20530	OIL SEAL, CRANKCASE (UPPER)
14	25-31932	"O" RING, CRANKCASE (UPPER)
15	15-26931	SHIM, SPACER TO CRANKCASE TOP (.015)
16	23-26563	SPACER, HOLD DOWN RING TO CRANKCASE TOP
17	29799	RING, MAGNETO HOLD DOWN
18	10-28802	SCREW, HOLD DOWN RING TO CRANKCASE TOP
19	30-63326T	BEARING, BALL - CRANKCASE (LOWER)
20	26-16977	OIL SEAL, CRANKCASE (LOWER)
21	23-29736	SLEEVE, PROTECTOR - CRANKSHAFT
22	25-8M0204650	"O" RING, CRANKSHAFT PROTECTOR SLEEVE
23	27-28085	GASKET, CYLINDER BLOCK TO BAFFLE PLATE
24	28086	PLATE, BAFFLE - EXHAUST MANIFOLD
25	27-28090	GASKET, BAFFLE PLATE TO MANIFOLD COVER
26	28074	COVER, EXHAUST MANIFOLD
27	10-28636	SCREW, MANIFOLD COVER TO CYLINDER BLOCK
28	10-28635	SCREW, MANIFOLD COVER TO CYLINDER BLOCK (LOWER REAR)
29	30212	TERMINAL BLOCK, EXHAUST MANIFOLD COVER
30	10-72169	SCREW, TERMINAL BLOCK TO EXHAUST MANIFOLD COVER
31	10-8M0113176	SCREW, SHORTING SWITCH LEAD TO TERMINAL BLOCK
32	54-24836	CLIP, SHORTING SWITCH LEAD FASTENING
33	8M0084613	"D" WASHER, SHORTING SWITCH LEAD FASTENING SCREW
34	10-8M0113176	SCREW, SHORTING SWITCH LEAD CLIP FASTENING
35	27-26173	GASKET, CYLINDER BLOCK COVER
36	1009-1200	COVER, CYLINDER BLOCK
37	12-28518	WASHER, SPACING - RUBBER MOUNT STUD
38	11-22053	NUT, RUBBER MOUNT TO COVER
39	10-20653	SCREW, COVER TO CYLINDER BLOCK
40	11-24652	NUT, CYLINDER BLOCK COVER FASTENING SCREW
41	26174	COVER, TRANSFER PORT
42	32033	COVER, TRANSFER PORT - UPPER
43	32032	COVER, TRANSFER PORT - LOWER
44	12-69057	WASHER, TRANSFER PORT COVER SCREW
45	54-20534	CLAMP, HARNESS - IGNITION WIRES
46	12-20533	WASHER, HARNESS CLAMP SCREW
47	10-20540	SCREW, PORT COVER TO CYLINDER BLOCK
48	10-25299	SCREW, CRANKCASE TOP FASTENING
49	14-20747	TAB WASHER, TOP FASTENING SCREW
50	26799	BRACKET, TOP COWL MOUNTING
51	10-28782	SCREW, COWL MOUNTING BRACKET TO CRANKCASE
52	12-28518	WASHER, SPACING - RUBBER MOUNT STUD
53	11-22053	NUT, RUBBER MOUNT TO BRACKET
54	10-98260	SCREW, CENTER MAIN BEARING LOCK
55	14-20091	TAB WASHER, BEARING LOCK SCREW
56	10-69090	SCREW, CRANKCASE TO CYLINDER BLOCK (2-1/4")
57	10-26066	SCREW, CRANKCASE TO CYLINDER BLOCK (1-1/4")
58	10-21449	SCREW, CRANKCASE TO CYLINDER BLOCK (2")
59	10-26132	SCREW, CRANKCASE TO CYLINDER BLOCK (2-1/2")
60	11-29250	NUT, CRANKCASE FASTENING SCREW
61	25-25429	"O" RING, CRANKCASE FASTENING SCREW

▶DRIVE SHAFT HOUSING ASSEMBLY (53 parts)

Ref	OEM Part #	Part Name
1	1531-1630A4	DRIVE SHAFT HOUSING ASSEMBLY
2	17-29452	ROLL PIN, WATER PUMP CARTRIDGE
3	10-32089	SCREW, DRIVE - WATER PUMP CARTRIDGE
4	16-26324	STUD, DRIVE SHAFT HOUSING TO GEAR HOUSING
5	16-26776	STUD, DRIVE SHAFT HOUSING TO GEAR HOUSING
6	11-82670911	NUT, DRIVE SHAFT HOUSING TO GEAR HOUSING STUD
7	11-24652	NUT, POWERHEAD TO DRIVE SHAFT HOUSING
8	32-28136	TUBE, WATER INLET
9	26-26865	SEAL, RUBBER - WATER INLET TUBE
10	23-28135	SLEEVE, RUBBER - WATER INLET TUBE
11	25-62704	"O" RING, WATER INLET TUBE
12	12-20086	WASHER, WATER INLET TUBE LOCATION
13	27-28132	GASKET, POWERHEAD TO DRIVE SHAFT HOUSING
14	28119	COVER, EXHAUST RELIEF MUFFLER
15	27-28120	GASEKT, EXHAUST RELIEF MUFFLER COVER
16	10-8M0113176	SCREW, EXHAUST RELIEF MUFFLER COVER
17	35774	SOUND SEAL, DRIVE SHAFT HOUSING
18	28899	RETAINER, SOUND SEAL - AFT
19	28900	RETAINER, SOUND SEAL - FORWARD
20	54-28901	FASTENER, SOUND SEAL TO HOUSING
21	29082A1	LEVER, TOP COWL CLAMPING (PORT)
22	29083A1	LEVER, TOP COWL CLAMPING (STARBOARD)
23	11-30428	FASTENER, CLAMPING LEVER HOLDING - SEE NOTE BELOW
24	17-29077	ROLL PIN, CLAMPING LEVER (5/32 X 3/4)
25	23-31293	BUSHING, RUBBER - CLAMPING LEVER
26	18-210711	COTTER PIN, CLAMPING LEVER HOLDING - SEE NOTE BELOW
27	26836	LEVER, TROLL CONTROL
28	23-26841	BUSHING, NYLON - TROLL CONTROL LEVER
29	28112	ARM, TROLL CONTROL LEVER
30	13-25906	WASHER, WAVE - TROLL LEVER ARM
31	10-28249	SCREW, SET - ARM TO TROLL CONTROL LEVER
32	25-30258	GROMMET, RUBBER - SHORTING SWITCH LEAD HOLE
33	1534-1427	SADDLE
34	28932	BUMPER, RUBBER - SADDLE (UPPER)
35	10-28942	SCREW, RUBBER BUMPER TO SADDLE
36	85002	MOUNT, RUBBER (UPPER)
37	53-23720	RING, RETAINING - UPPER MOUNT
38	25155	COVER, UPPER MOUNT
39	10-28637	SCREW, UPPER MOUNT COVER RETAINING
40	79947A1	MOUNT, RUBBER (LOWER)
41	53-8M0051043	RING, RETAINING - LWOER MOUNT
42	25154	COVER, LOWER MOUNT
43	10-28637	SCREW, LOWER MOUNT COVER RETAINING
44	28334	BUMPER, RUBBER - SADDLE (LOWER)
45	10-28668	SCREW, RUBBER BUMPER TO SADDLE
46	12-20028	6WASHER, RUBBER BUMPER FASTENING SCREW
47	27-26818	GASKET, TRANSMISSION COVER
48	26824	COVER, TRANSMISSION
49	10-28639	SCREW, TRANSMISSION COVER TO DRIVE SHAFT HOUSING
50	10-79953Q04	SCREW, GEAR HOUSING VENT
51	12-191833	WASHER, GEAR HOUSING VENT SCREW
52	10-28638	SCREW, TRANSMISSION COVER FLUSHING HOLE
53	12-22937	WAHER, FLUSHING HOLE SCREW

▶FUEL PUMP AND FUEL LINE ASSEMBLY (24 parts)

Ref	OEM Part #	Part Name
1	30269A2	FUEL PUMP ASSEMBLY (SEE NOTE BELOW)
2	27-23005	GASKET, CHECK VALVE TO PUMP HOUSING
3	21-8M0082362	VALVE, CHECK
4	23004	RETAINER, CHECK VALVE
5	10-43725	SCREW, RETAINER TO HOUSING
6	27-24863	GASKET, FUEL PUMP
7	23014	DIAPHRAGM, FUEL PUMP
8	10-29246	SCREW, FUEL PUMP MOUNTING (1-5/8)
9	10-28712	SCREW, FUEL PUMP MOUNTING(1-5/8)
10	32-30040	FUEL LINE, FUEL PUMP TO CARBURETOR (5-1/4)
11	22-59351	FITTING, FUEL PUMP OUTLET
12	22-59351	FITTING, FUEL PUMP INLET
13	22-22995	FITTING, FUEL PUMP FITTING TO FUEL LINE
14	22-22946	SLEEVE, RUBBER
15	22-22948	NUT, FITTING
16	32-30301	FUEL LINE, ADAPTOR TO FUEL PUMP (11-5/8")
17	30188	CUP WASHER, ADAPTOR
18	24-23067T	SPRING, ADAPTOR STEM
19	25-16524	"O" RING, ADAPTOR STEM
20	23069	STEM, CHECK UNIT ADAPTOR
21	22833	ADAPTOR, CHECK UNIT
22	10-21091	SCREW, CHECK UNIT ADAPTOR TO STEERING BRACKET
23	12-20028	WASHER, ADAPTOR FASTENING SCREW
24	11-8267139	NUT, ADAPTOR FASTENING SCREW

▶GEAR HOUSING ASSEMBLY (37 parts)

Ref	OEM Part #	Part Name
1	1614-1440A1	GEAR HOUSING ASSEMBLY
2	31-28157	BEARING, ROLLER - PROP AND DRIVE SHAFT
3	16-26809	STUD, GEAR HOUSING TO DRIVE SHAFT HOUSING
4	10-21153	SCREW, PINION GEAR TO DRIVE SHAFT
5	14-20806	TAB WASHER, PINION GEAR SCREW
6	43-27997	GEAR, PINION
7	26315A1	PILOT ASSEMBLY, GEAR HOUSING
8	25-26317	"O" RING, PILOT ASSEMBLY (LOWER)
9	25-8M0204651	"O" RING, PILOT ASSEMBLY (UPPER)
10	15-21886A1	SHIM, BALL BEARING TO PILOT
11	30-21776	BEARING, BALL - PILOT AND DRIVE SHAFT
12	45-26694A1	DRIVE SHAFT ASSEMBLY (LOWER)
13	23-26660	BUSHING, DRIVE SHAFT
14	17-20201	DOWEL, HOLLOW - DRIVE SHAFT HOUSING STUD
15	35-26314	SCREEN, WATER INLET - GEAR HOUSING
16	44-28275A2	SHAFT, PROPELLER
17	43-27998	GEAR, PROPELLER
18	17-813061	PIN, PROPELLER GEAR TO SHAFT
19	15-26320A1	SHIM, "L" WASHER TO GEAR HOUSING
20	12-26309	"L" WASHER, BALL BEARING
21	30-63326T	BEARING, BALL - PROPELLER GEAR
22	15-21158A1	SHIM, BALL BEARING TO SNAP RING
23	53-21159	RING, SNAP - BALL BEARING TO PROPELLER GEAR
24	25-20826	"O" RING, BEARING CARRIER ASSEMBLY
25	28460A1	BEARING CARRIER ASSEMBLY
26	31-28157	BEARING, ROLLER - BEARING CARRIER
27	26-27163	OIL SEAL, BEARING CARRIER (SPRING LOADED)
28	26-26805	OIL SEAL, BEARING CARRIER
29	26310	COVER, GEAR HOUSING
30	10-79953Q04	SCREW, GREASE FILLER HOLE
31	12-191833	WASHER, GREASE FILLER HOLD SCREW
32	23-85964A1	COLLAR, PROPELLER SHAFT
33	48-28036A1	PROPELLER ASSEMBLY
34	11-64075A1	SPACER, PROPELLER (SPLINED)
35	12-27025	WASHER, PROPELLER NUT
36	11-27687	NUT, PROPELLER
37	11-82670911	NUT, GEAR HOUSING TO DRIVE SHAFT HOUSING STUDS

▶MAGNETO ASSEMBLY (51 parts)

Ref	OEM Part #	Part Name
1	398-1736A1	STATOR ASSEMBLY, COMPLETE
2	398-1736	STATOR AND CORE
3	398-963	SCREW, CORE FASTENING
4	13-21144	LOCKWASHER, CORE FASTENING SCREW
5	398-173	COIL, IGNITION
6	10-21130	SCREW, GROUND TERMINAL
7	398-190	COVER, BREAKER COMPARTMENT SEALING
8	10-30429	SCREW, SEALING COVER FASTENING
9	398-174	BREAKER ASSEMBLY
10	10-20650	SCREW, BREAKER FASTENING
11	12-21135	WASHER, BREAKER FASTENING SCREW
12	13-21134	LOCKWASHER, BREAKER FASTENING SCREW
13	10-23976	SCREW, BRAKER CONNECTION
14	398-693	CONDENSER
15	10-21136	SCREW, CONDENSER FASTENING
16	13-21134	LOCKWASHER, CONDENSER FASTENING SCREW
17	398-192	WICK, FELT
18	398-193	PLUG, FELT
19	84-821945A46	LEAD WIRE
20	20117	MARKER, "TOP" - LEAD WIRE
21	32-21137	TUBE, LEAD WIRE (PORT SIDE)
22	23-25217	BUSHING, LEAD WIRE (STARBOARD SIDE)
23	54-24836	CLAMP, PLASTIC - LEAD WIRE TO STATOR
24	10-20650	SCREW, LEAD WIRE CLAMP (SHORT)
25	10-21139	SCREW, LEAD WIRE CLAMP (LONG)
26	12-21135	WASHER, LEAD WIRE CLAMP SCREW
27	13-21134	LOCKWASHER, LEAD WIRE CLAMP SCREW
28	398-1098	BUSHING, LEAD WIRES
29	85-63709A1	PROTECTOR, SPARK PLUG
30	398-1872	GROUND LEAD, MAGNETO TO SHORTING SWITCH TERMINAL BLOCK
31	23-30419	SLEEVE, GROUND LEAD INSULATION
32	25-29051	GROMMET, GROUND LEAD THRU STATOR PLATE
33	33-813416	SPARK PLUG (AC-M44C)
34	26566A8	THROTTLE CONTROL CAM ASSEMBLY
35	23-26560	SPACER, THROTTLE CAM
36	10-20616	SCREW, THROTTLE CAM TO STATOR PLATE (SHORT)
37	10-39514	SCREW, THROTTLE CAM TO STATOR PLATE (LONG)
38	12-20028	WASHER, CAM MOUNTING SCREW (LONG)
39	29013	IDLE STOP, ADJUSTABLE
40	10-32417	SCREW, IDLE STOP TO TOP COWL BRACKET
41	12-20028	WASHER, IDLE STOP FASTENING SCREW
42	11-24652	NUT, IDLE STOP SCREW
43	26565	CLIP, MAGNETO HOLD DOWN
44	10-29248	SCREW, HOLD DOWN CLIP TO MAGNETO
45	24-27087	SPRING, HOLD DOWN CLIP SCREW
46	28-20094	KEY, FLYWHEEL
47	11-8M0214915	NUT, FLYWHEEL
48	30046	STOP, MAGNETO ADVANCE
49	10-30095	SCREW, ADJUSTMENT - MAGNETO ADVANCE STOP
50	11-29798	NUT, ADJUSTMENT STOP SCREW
51	19-29900	PLUG, PLASTIC - FLYWHEEL SCREW HOLES

▶MISCELLANEOUS PARTS/ACCESSORIES (1 parts)

Ref	OEM Part #	Part Name
-	92-86166Q1	GLUE (BLANKET ADHESIVE)

▶PISTON AND CONNECTING ROD ASSEMBLY (9 parts)

Ref	OEM Part #	Part Name
1	600-2748A2	CONNECTING ROD ASSEMBLY
2	10-45379	SCREW, CONNECTING ROD
3	29-20046T	BEARING, NEEDLE - CRANKPIN
4	11-20061	NUT, CONNECTING ROD SCREW
5	12-28121	WASHER, NEEDLE BEARING RETAINING (1/16")
6	29-20063	BEARING, NEEDLE - PISTON PIN
7	724-2537A2	PISTON AND PISTON PIN ASSEMBLY
8	40-20057	LOCK RING, PISTON PIN
9	39-27841A12	RING, PISTON

▶STEERING HANDLE ASSEMBLY (38 parts)

Ref	OEM Part #	Part Name
1	28702A1	STEERING HANDLE ASSEMBLY
2	24-28101	SPRING, REVERSE SHAFT TENSION
3	28099	SHAFT, REVERSE STOP
4	12-28105	WASHER, REVERSE SHAFT
5	28098	GRIP, RUBBER - STEERING HANDLE
6	30-28103	BALL, STEEL - REVERSE SHAFT LOCKING
7	23-28104	BUSHING, NYLON - HANDLE SHAFT (3/4")
8	28097	TUBE, STEERING HANDLE
9	23-28100	BUSHING, NYLON - HANDLE SHAFT (5/16")
10	12-20084	WASHER, STEERING HANDLE SHAFT
11	24-26703	SPRING, STEERING HANDLE SHAFT
12	14-26706	TAB WASHER, YOKE PIN HOLDING
13	30235	YOKE, STEERING HANDLE
14	17-26862	PIN, YOKE TO STEERING HANDLE SHAFT
15	29518A1	ADAPTOR, HANDLE
16	10-21091	SCREW, HANDLE ADAPTOR CLAMPING
17	11-8267089	NUT, HANDLE ADAPTOR CLAMPING SCREW
18	11-826709109	NUT, HANDLE ADAPTOR CLAMPING SCREW
19	12-20533	WASHER, HANDLE ADAPTOR CLAMPING SCREW
20	28480A2	CONTROL SHAFT ASSEMBLY
21	10-96138	SCREW, CONTROL SHAFT TO STEERING BRACKET
22	15-28485	SHIM, ADAPTOR TO STEERING ARM BRACKET
23	30205	BRACKET, STEERING ARM
24	10-21259	SCREW, STEERING BRACKET TO SADDLE (1-1/2")
25	10-21807	SCREW, STEERING BRACKET TO SADDLE (1-3/4")
26	11-24652	NUT, REAR BRACKET FASTENING SCREWS
27	26711	PIVOT, STEERING HANDLE ADAPTOR TO BRACKET
28	15-26707	SHIM, ADAPTOR PIVOT TO BRACKER (.015)
29	10-28592	SCREW, HANDLE PIVOT FASTENING
30	30244	SHORTING SWITCH ASSEMBLY
31	24-30247A1	SPRING AND CONTACT ASSEMBLY
32	23987	COVER, RUBVER - SHORTING SWITCH
33	30260	TERMINAL, SHORTING SWITCH LEAD
34	53-46250	RING, RETAINING - SHORTING SWITCH TO BRACKET
35	25-30226	GROMMET, RUBBER - SHORTING SWITCH LEADS THRU BRACKET
36	54-24836	CLIP, SHORTING SWITCH LEAD TO BRACKET
37	8M0084613	"O" WASHER, SHORTIN GSWITCH LEAD CLIP FASTENING SCREW
38	10-8M0113176	SCREW, SHORTING SWITCH LEAD CLIP FASTENING

▶SYNCHRONIZE THROTTLE AND SHIFT CONTROL (57 parts)

Ref	OEM Part #	Part Name
1	28089	BODY, SYNCHRONIZER
2	23-28247	BUSHING, NYLON - SUPPORT SHAFT TO BODY (7/8")
3	28215	SHAFT, SUPPORT - PRIMARY DRIVE
4	28808	SHAFT, INPUT - PRIMARY DRIVE
5	28216	BALL JOINT, NYLON - INPUT SHAFT
6	17-28235	PIN, BALL JOINT TO INPUT AND SUPPORT SHAFT
7	23-20571	BUSHING, RUBBER - INPUT SHAFT
8	23-28478	SLEEVE, INNER - INPUT SHAFT
9	32-28475	TUBE, OUTER - INPUT SHAFT (RUBBER)
10	24-28234	SPRING, INPUT SHAFT
11	28153	ECCENTRIC, PRIMARY DRIVE SHAFT
12	28213A1	LINK, PRIMARY TO MAGNETO CONTROL LEVER
13	28226A1	ACTUATOR ASSEMBLY, SHIFT CAM
14	29-25015	PIN, ROLLER - ECCENTRIC POSITIONING
15	12-28463	WASHER, ACTUATOR FASTENING SCREW
16	23-28462	SPACER, ACTUATOR FASTENING SCREW
17	10-28425	SCREW, ACTUATOR TO PRIMARY DRIVE SHAFT
18	10-69035	SCREW, SYNCHRONIZER BODY TO DRIVE SHAFT HOUSING
19	28111	LEVER, MAGNETO CONTROL
20	23-26841	BUSHING, NYLON - MAGNETO CONTROL LEVER
21	23-26856	BUSHING, NYLON - MAGNETO CONTROL LEVER (1/4")
22	28354	CAM, CONTROL LEVER
23	28353	PLATE, CLUTCH - REAR
24	12-20583	WASHER, CONTROL LEVER TO BODY
25	18-28365	COTTER PIN, LOCK - CONTROL LEVER TO CAM
26	23-28352	BUSHING, NYLON - SYNCHRONIZER BODY (1")
27	28355	PLATE, CLUTCH - FRONT
28	28356	PLATE, CLUTCH RETAINING (NOT REQUIRED ON LATER ENGINES)
29	24-28357	SPRING, CLUTCH PLATE TENSION
30	16-69016	STUD, CLUTCH RETAINING PLATE TO CAM
31	11-20110	NUT, CLUTCH RETAINING PLATE STUD
32	28218A1	SHIFT CAM ASSEMBLY
33	28221	LEVER, DETENT
34	24-28233	SPRING, TENSION - DETENT LEVER
35	23-26841	BUSHING, NYLON - SHIFT CAM SHAFT (5/16")
36	12-20546	WASHER, SHIFT CAM SHAFT
37	18-210711	COTTER PIN, SHIFT CAM SHAFT TO BODY
38	13-27071	WASHER, WAVE - SHIFT CAM PIN
39	18-26953	COTTER PIN, UPPER SHIFT SHAFT TO SHIFT CAM
40	28109	LEVER, CAM CONTROL
41	28675	LINK, DRAG - TROLL CONTROL
42	10-28674	SCREW, DRAG LINK TO TROLL ARM AND CAM LEVER
43	17-28673	PIN, ANCHOR - TROLL CONTROL ARM
44	28112	ARM, TROLL CONTROL LEVER
45	13-25906	WASHER, WAVE - TROLL CONTROL LEVER
46	10-28249	SCREW, SET - ARM TO TROLL CONTROL LEVER
47	23-26841	BUSHING, NYLON - TROLL CONTROL ELVER
48	26836	LEVER, TOLL CONTROL
49	10-34697	BOLT, SWIVEL - MAGNETO CONTROL LEVER - LATE MODELS
50	31428	LINK, ADJUSTING - MAGNETO CONTROL ROD - LATE MODELS
51	12-26014	WASHER, SWIVEL BOLT TO ADJUSTING LINK - LATE MODELS
52	28367	ROD, MAGNETO CONTROL
53	11-68219	NUT, LOCK - ADJUSTING LINK
54	18-26811	COTTER PIN, ADJUSTING LINK TO SWIVEL BOLT
55	28232	BOLT, TOGGLE-THROTTLE CONTROL CAM
56	13-29402	WASHER, WAVE - TOGGLE BOLT
57	11-826709109	NUT, TOGGLE BOLT FASTENING

▶TOP COWL AND STARTER ASSEMBLY (33 parts)

Ref	OEM Part #	Part Name
1	176-1425	TOP COWL
2	31100A3	PLAQUE ASSEMBLY, TOP COWL
3	26183A5	EMBLEM, TOP COWL PLAQUE
4	12-27149	WASHER, NYLON - FRONT PLAQUE TO TOP COWL
5	53-25539	FASTENER, FRONT PLAQUE TO TOP COWL
6	37-31869	DECAL, FRONT PLAQUE - TOP COWL
7	37-89323A80	DECAL SET, TOP COWL
8	28041	COVER, TRIM - TOP COWL
9	10-28156	SCREW, TRIM COVER TO TOP COWL
10	33575	BLANKET, TOP COWL - FRONT AND SIDE
11	28278	BLANKET, TOP COWL - REAR
12	28823	SCREEN, VENT - TOP COWL
13	10-69079	SCREW, SCREEN TO TOP COWL
14	28113	BRACKET, TOP COWL MOUNTING
15	27-28448	GASKET, TOP COWL MOUNTING BRACKET
16	10-29072	SCREW, MOUNTING BRACKET TO TOP COWL
17	11-27164	NUT, MOUNTING BRACKET SCREW
18	20155	RETAINER, STARTER SPRING
19	24-29340T02	SPRING, STARTER REWIND
20	23-20159	BUSHING, SPRING GUIDE
21	50-64008A1	SHEAVE ASSEMBLY, STARTER
22	20162	PAWL, STARTER
23	13-29402	WASHER, WAVE - STARTER PAWL
24	23-20158	SPACER, SHEAVE SHAFT
25	26179	RETAINER, WAVE WASHER
26	12-26180	WASHER, WAVE WASHER RETAINER
27	13-20160	WASHER, WAVE - STARTER SHEAVE TENSION
28	20164	PLATE, RETAINER - STARTER PAWL
29	20157	SHAFT, SHEAVE
30	14-20165	TAB WASHER, SHEAVE SHAFT NUT
31	11-20166	NUT, SHEAVE SHAFT(LEFT HAND THREAD)
32	50-12066Q10	STARTER CABLE ASSEMBLY
33	92-271091	ADHESIVE COMPOUND, EMBLEM FASTENING (3-1/2 OZ. KIT)

▶WATER PUMP CARTRIDGE, DRIVE SHAFT AND TRUNNION CARRIER ASMBL (52 parts)

Ref	OEM Part #	Part Name
1	25-26802	"O" RING, UPPER DRIVE SHAFT
2	12-20684	SLINGER, CENTRIFUGAL
3	29436	PLATE, TOP - WATER PUMP
4	47-26554	IMPELLER, WATER PUMP
5	46-29445A1	WATER PUMP CARTRIDGE ASSEMBLY
6	20811	SLEEVE, WATER PUMP CARTRIDGE
7	29435	PLATE, BOTTOM
8	26-20070	OIL SEAL, WATER PUMP CARTRIDGE
9	25-29439	"O" RING, WATER PUMP CARTRIDGE
10	29437A1	SEAL RETAINER ASSEMBLY
11	26-79831	OIL SEAL, RETAINER
12	25-20812	RING, RUBBER - SEALING
13	12-29687	"L" WASHER, WATER PUMP CARTRIDGE
14	26783	SLEEVE, DRIVE SHAFT BALL BEARING
15	30-21776	BEARING, BALL - UPPER DRIVE SHAFT
16	15-26728A1	SHIM, BALL BEARING TO DRIVE SHAFT
17	53-29438	RING, LOCK - WATER PUMP CARTRIDGE AND BEARING
18	45-29444A1	DRIVE SHAFT ASSEMBLY(UPPER)
19	23-26660	BUSHING, DRIVE SHAFT
20	28-28784	KEY, DRIVE SHAFT
21	12-27988	WASHER, CLUTCH RETAINING
22	24-27991	SPRING, NEUTRAL
23	12-26835	WASHER, THRUST - NEUTRAL SPRING
24	43-27994A1	INPUT DRUM AND GEAR ASSEMBLY
25	23-26660	BUSHING, INPUT GEAR AND DRUM
26	27995	SLEEVE, REVERSE CONTROL -TRUNNION CARRIER
27	27987A2	TRUNNION CARRIER ASSEMBLY, COMPLETE
28	27987A1	TRUNNION CARRIER ASSEMBLY
29	43-26688	GEAR, IDLER
30	12-29447	WASHER, THRUST - IDLER GEAR
31	27986	SHAFT, IDLER GEAR TO CARRIER
32	28000	SHAFT, PILOT - TRUNNION CARRIER
33	28-28002	KEY, SPRING CLUTCH
34	29-26689	PIN, ROLLER - KEY AND SHAFT HOLDING
35	12-26661	WASHER, THURST - PILOT SHAFT (LOWER - .020)
36	12-29446	WASHER, THRUST - PILOT SHAFT (UPPER - .031)
37	27992	SLEEVE, TRUNNION CARRIER
38	27072	SHAFT, UPPER SHIFT
39	11-8267086	NUT, PUSH LINK TO UPPER SHIFT SHAFT
40	11-68219	NUT, ADJUSTING - SLEEVE LOCKING
41	29289A1	SHIFT ROD ASSEMBLY, LOWER
42	27010	SHAFT, CONTROL - TRANSMISSION
43	25-48171	"O" RING, TRANSMISSION CONTROL SHAFT
44	13-27071	WASHER, WAVE - LOWER SHIFT ROD
45	18-27789	COTTER PIN, LOWER SHIFT ROD TO CONTROL SHAFT
46	27767	PAWL, NEUTRAL
47	27766	PAWL, REVERSE
48	27016	SHAFT, NEUTRAL AND REVERSE PAWL
49	24-27014	SPRING, NEUTRAL PAWL
50	24-27013	SPRING, REVERSE PAWL
51	17-26926	PIN, PAWL SPRING RETAINING
52	23-26927	SPACER, CONTROL PAWL SPRING

100-Hour / Annual Service Checklist

Regular maintenance keeps your Mercury 100, 150, 200, 250 running reliably season after season. Most of these tasks can be performed with basic tools and the factory service manual.

Replace water pump impeller and inspect wear plate
Change engine oil and oil filter (check drain plug washer)
Replace spark plugs and check ignition timing
Drain and refill lower unit gear oil; inspect for water contamination
Inspect fuel lines, primer bulb, and fuel filter for deterioration
Check and replace sacrificial anodes (zinc or aluminum)
Inspect propeller for damage; check shaft seal and cotter pin
Check valve clearance (refer to service manual for specifications)
Lubricate all grease points (steering, tilt tube, shift linkage)
Inspect control cables and throttle/shift linkage for smooth operation

Pro Tip: Always flush the engine with fresh water after saltwater use — even a quick 10-minute flush significantly extends component life.
Pro Tip: Use fuel stabilizer in the tank before winter storage, and fog the cylinders to prevent internal corrosion during extended periods of non-use.

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