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9959619-1-M-Briggs and Stratton-491055T-Spark Plug
Part Location Diagram of 491055T Briggs and Stratton Spark Plug
See part S-9-08 in the diagram
Replacing your Craftsman Lawn Mower Spark Plug
9959619-1-S-Briggs and Stratton-491055T-Spark Plug 360 view
( Grid squares measure 1x1 inch )
9959619-1-S-Briggs and Stratton-491055T-Spark Plug 9959619-2-S-Briggs and Stratton-491055T-Spark Plug 9959619-1-S-Briggs and Stratton-491055T-Spark Plug 360 view
Part Location Diagram of 491055T Briggs and Stratton Spark Plug Replacing your Craftsman Lawn Mower Spark Plug

Spark Plug 491055T

Manufactured by:
Briggs and Stratton
ERP Number:
ERP9959619
Part Number:
491055T
Original Equipment Manufacturer ?
$5.95
★★★★★
★★★★★
21 Reviews
In Stock
Delivers in 3-5 Business Days!

Easy 

1- 2 hours 

(28 rated repairs) ?

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Description Frequently Purchased Together Troubleshooting Repair Videos Reviews Questions & Answers Repair Instructions Model Cross Reference

Product Description

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This OEM spark plug is a high-quality replacement part designed for gas-fueled engines and is sold individually. Its primary function is to deliver an electric current from the ignition system to the engine’s combustion chamber, igniting the air-fuel mixture with a reliable spark. Over time, spark plugs can become fouled due to issues such as incorrect air/fuel ratios, worn piston rings, or carbon buildup. For optimal engine performance, it’s recommended to replace a dirty spark plug rather than attempting to clean it. Always refer to your product’s owner’s manual to ensure the spark plug is properly gapped before installation.

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Troubleshooting

This part works with the following brands:
  • Craftsman
  • Toro
This part works with the following products:
  • Lawn Mower
Part# 491055T replaces these:
4217,

Videos For installing this part.

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Replacing your Spark Plug
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Customer Part Reviews

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4.6
Average Rating (out of 5):
★★★★★
★★★★★
(21 Reviews)
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Sorry, we couldn't find any existing reviews that matched. Try using some different or simpler keywords.
★★★★★
★★★★★
GREAT SERVICE
After I placed my order I was expecting a long wait but to my surprise I received my spark plug in just a few days. Great service!
Guest - April 11, 2020
Verified Purchase
★★★★★
★★★★★
Correct part, easy to find, fast delivery.
Spark plug arrived in great condition. Fit my mower and it is now running great.
Scott - June 15, 2020
Verified Purchase
★★★★★
★★★★★
Good price, all parts in stock, quick delivery, what more needs to be said!
Good price, all parts in stock, quick delivery, what more needs to be said!
Thomas - April 15, 2021
Verified Purchase
★★★★★
★★★★★
Needed part
Works great
Guest - June 22, 2021
Verified Purchase
★★★★★
★★★★★
The exact plug number I needed.
Good plug.
Guest - May 6, 2022
Verified Purchase
★★★★★
★★★★★
Lawn mower spark plug
Ive done business with ereplacement parts for many years. They have a great selection for just about any mower, string trimmer or blower. Since the majority of replacement parts are OEM, your assured it fits right at a competitive price. There is no one else that I have found with one stop shopping capability for all your gas or electric powered lawn tool repair parts. Give them a try.
James - July 19, 2022
Verified Purchase
★★★★★
★★★★★
Replacement Spark Plug
The part arrived quickly. It was the correct part. My lawn mower is working again.
Guest - November 22, 2022
Verified Purchase
★★★★★
★★★★★
easy repair
parts were as ordered. great fit. Mower running like new...
Guest - November 26, 2022
Verified Purchase
★★★★★
★★★★★
Good Service
Good products at a good price. If need help the phone service is very helpful.
Guest - January 5, 2023
Verified Purchase
★★★★★
★★★★★
Easy to repair with the right parts
I ordered the parts I needed and the repair went smoothly. The parts were delivered quickly and the my mower was running in minutes.
Guest - May 18, 2023
Verified Purchase
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Questions & Answers

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Customer Repair Instructions

All our customer repair instructions are solicited directly from other customers just like you who have purchased and replaced this exact part.

Easy 

1- 2 hours 

(28 rated repairs) ?
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Sorry, we couldn't find any existing installation instruction that matched.

Generator had sat for oh 8 years. Carburetor was gummed/varnish up and inoperable, plugs fowled out so it was easier and time saving to replace the parts.

Roy from Chesapeake, Virginia

8 of 8 people found this instruction helpful.
Difficulty Level:
Easy
Total Repair Time:
1- 2 hours
Tools:
Screw drivers, Socket set, Wrench set
Parts Used:
491055T, 809011
Removed the fly wheel cover the intake manifold then the carburetor, re-installed new carburetor re-installed manifold then the flywheel cover, squirt some oil in each cylinder installed the new plugs gapped at 0.030 choked carburetor then cranked oh 10 seconds then gave shot of starter fluid and hit the start switch again and within oh 3 -5 seconds it started and I let it run for 10 minutes, now my 15kw generator is up and running I have no worries when loss of power comes my way now, lol, once again thank you eReplacement parts
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Lawn tractor would not start, no spark at plug

Michael from RENO, Nevada

7 of 7 people found this instruction helpful.
Difficulty Level:
Easy
Total Repair Time:
15 - 30 mins
Tools:
Socket set, Wrench set
Parts Used:
595304, 491055T
1. Removed plastic engine covers.
2. Removed spark plug.
3. Connected spark plug to cable and placed on cylinder head for a ground path.
4. Cranked engine and observed no spark.
5. Removed shutoff wire from magneto and repeated (isolates any issues with other wiring), still no spark.
6. Install new magneto at farthest back position and snug the bolts.
7. Rotate flywheel until magnets align with magneto.
8. Place business card between magneto and flywheel.
9. Loosen magneto bolts and allow magnets to pull magneto to flywheel.
10. Tighten magneto bolts.
11. Remove card and rotate flywheel by hand to ensure there is no contact (will be very close)
12. Reinstall spark plug and connect wire.
13. Start and run for test, then reinstall engine covers.
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General tune up, oil and filter, spark plugs, air filter, etc

Daniel from ELM GROVE, Wisconsin

5 of 5 people found this instruction helpful.
Difficulty Level:
Easy
Total Repair Time:
30 - 60 mins
Tools:
Pliers, Socket set
Parts Used:
491055T, 792105, 845125, 492932B
Operation are self explanatory.
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Carbon build up in combustion chamber.

Carl from Jackson, Louisiana

5 of 5 people found this instruction helpful.
Difficulty Level:
A Bit Difficult
Total Repair Time:
More than 2 hours
Tools:
Socket set, Wrench set
Parts Used:
491055T, 692236, 794114, 272475S, 100106
1. Remove overhead valve cover.
2. Remove push rods.
3. Remove old spark plug.
4. Remove intake and exhaust manifolds.
5. Remove engine head bolts and head.
Used solvent to clean carbon (baked in coke) from head, valves, piston head and exhaust port. Cleaned gasket surfaces and installed head, push rods, int ake and exhaust manifolds. Checked valve clearances and installed valve rocker cover with gasket and sealant. This was a 21 hp B&S Intek engine. This must be done every 2 to 3 grass cutting seasons (book says every 300 hours) to keep these engines from burning oil and for them to run smoothly.
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Maintenance

Eric from Gulfport, Mississippi

4 of 4 people found this instruction helpful.
Difficulty Level:
Easy
Total Repair Time:
15 - 30 mins
Tools:
Pliers, Socket set
Parts Used:
394358B, 794421, 491055T
Replaced air filter. Replaced fuel filter. Used vise grips to stop the flow of gas and pliers to remove the spring clips (slide them back on the fuel line) holding the fuel filter to fuel lines. Replaced spark plug. Used ratchet, socket and extension to remove spark plug and replace with a new one. Set gap using gap gauge.
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Pressure washer engine left standing for 7 years, carb gummed up, air filter broken off. Gas pouring out of carb.

Robert from Duluth, Georgia

3 of 3 people found this instruction helpful.
Difficulty Level:
Easy
Total Repair Time:
1- 2 hours
Tools:
Pliers, Socket set
Parts Used:
491588B, 491055T, 695157, 692584, 493537S, 398187
1) Stripped the carb, ordered parts
2) Soaked the carb parts in NAPA carb cleaner
3) reassembled using the genuine B&S parts obtained from ereplacementparts.com
4) installed new plug
5) straightened out the bent air filter bracket, installed new cover and element.
6) engine started and ran on 3rd or 4th pull
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Water pump was not working or didi not produce high presure.

Roberto from Bayamon, Puerto Rico

2 of 2 people found this instruction helpful.
Difficulty Level:
A Bit Difficult
Total Repair Time:
30 - 60 mins
Tools:
Socket set, Wrench set
Parts Used:
491055T, 796335, 493537S
The conecting pin or key between the motor and the pump was broken. It was replaced and it is working very ell.
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Engine smoking

Ronald from Hazleton, Pennsylvania

2 of 2 people found this instruction helpful.
Difficulty Level:
Very Difficult
Total Repair Time:
More than 2 hours
Tools:
Nutdriver, Pliers, Screw drivers, Socket set, Wrench set
Parts Used:
491055T, 791118, 796584, 697110, 690968, 696854
Removed engine, removed head, valves, opened case to check rings. Rings OK, replaced piston and side case gasket. Removed valves, lapped valve seats, replaced valve stem seal. Replaced head with new gasket. Job complete.
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Intake push rod bent

Harold from Iowa Park, Texas

2 of 2 people found this instruction helpful.
Difficulty Level:
A Bit Difficult
Total Repair Time:
1- 2 hours
Tools:
Nutdriver, Screw drivers, Socket set, Wrench set
Parts Used:
491055T, 692003, 795387, 794152, 697110, 492932B
I jumped the gun initially and pulled the engine from the tractor, thinking the connecting rod had broken. I should have checked the valve push rods first. That would have saved me the time of removing the engine from the tractor and replacing the pan gasket and crankshaft oil seal.
It was pretty simple after I determined that my p roblem was the push rods. I removed the bent rod installed the new one I purchased from eReplacementParts.com. Adjusted the valves(You can find several youtube videos to guide you through this procedure). The engine started right up and I mowed about two hours with it this weekend.
I wish I could tell you why the push rod bent, but I can\'t. If anyone has an explnation I would love to here it.
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Lawn tractor needed servicing

Stan from Port Jefferson Station, New York

2 of 2 people found this instruction helpful.
Difficulty Level:
Easy
Total Repair Time:
30 - 60 mins
Tools:
Socket set, Wrench set
Parts Used:
597000601, 33742, 491055T, 532422719, 795115, 532106933
1 To change the blade I lifted up the tractor with a floor jack as far as i could get it and then chocking the rear wheels so the tractor would not roll back.
2 Then with a impact gun and socket I removed the bolts that held the blades in place.
3 Reversing the procedure first starting the retaining bolts by hand I put the new blades on the tractor and lowered the machine.
4 For the tune up I took out the spark plug using my 5/8\" long socket.
5 Reversing the procedure I first gaping the spark plug the the proper specs then putting a light coating of Never Cease on the threads of the spark plug and reinstalled the plug first starting the plug by hand so the threads do not cross and then snugging it down.
6 The air filter I just took the old one out and placed the new one in the same way.
7. The Mulching attachment simply following the direction that came with the item and using the hardware provided.
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Model Cross Reference

This part works with the following models:
ERP Number: ERP9959619
Manufacturer Part Number: 491055T
Brand Model Number Description
Toro 1-0100 Lawn Tractor - Lawn Tractor
Craftsman 536373730 Lawn Mower - Craftsman 18 In-3.0 Reel Mower
Craftsman 536375600 Lawn Mower - Craftsman 18 Inch - 3.0 Reserve Power Reel Mower
Craftsman 536375700 Lawn Mower - Craftsman 18 Inch Reel Mower
Craftsman 536375701 Lawn Mower - Craftsman 18 In. Power Reel Mower
Craftsman 536375702 Lawn Mower - 18" Reserve Power Reel Mower
Craftsman 536375750 Lawn Mower - Craftsman 18 In-3, 9 Reserve Power Reel Mower
Craftsman 536376600 Lawn Mower - 18 In Hand Reel Lawnmower
Craftsman 536376610 Lawn Mower - Sears 18" Hand Reel Lawnmower
Craftsman 53681101 Lawn Mower - 18 Inch Reel Power Mower
Craftsman 53681640 Lawn Mower - Craftsman 18 Inch Electric Reel Mower
Craftsman 536816701 Lawn Mower - Craftsman 18 In. Power Reel Mower
Craftsman 536816702 Lawn Mower - 18 In. - 3.0 Reverse Power Reel Mower
Craftsman 53681960 Lawn Mower - 18 Inch Craftsman Reel Power Mower
Craftsman 53681961 Lawn Mower - 18 Inch Craftsman Reel Power Mower
Craftsman 53681962 Lawn Mower - Sears 18 Inch Craftsman Reel Power Mower
Craftsman 53681963 Lawn Mower - Craftsman 18 In. Power Reel Mower
Craftsman 53681964 Lawn Mower - Craftsman 18 Inch Power Reel Mower
Craftsman 536819641 Lawn Mower - Craftsman 18 Inch Power Reel Mower
Craftsman 53681970 Lawn Mower - 18" Craftsman Reel Power Mower
Craftsman 53681971 Lawn Mower - Craftsman 18 Inch Reel Power Mower
Craftsman 53681972 Lawn Mower - Craftsman 18 Inch Reel Power Mower
Craftsman 53681973 Lawn Mower - 18 Inch Craftsman Reel Power Mower
Craftsman 53681974 Lawn Mower - 18 Inch Craftsman Reel Power Mower
Craftsman 53681975 Lawn Mower - 18 Inch Craftsman Reel Power Mower
Craftsman 53681976 Lawn Mower - 21 Inch Craftsman Reel Power Mower
Craftsman 53681978 Lawn Mower - 21 Inch Craftsman Reel Power Mower
Craftsman 53682351 Lawn Mower - Craftsman 21 In Drag Mower
Craftsman 53691210 Lawn Mower - Craftsman 18 In Power Reel Mower
Craftsman 53691300 Lawn Mower - Craftsman 18" Electric Reel Mower
Spark Plug
$ 5.95
In Stock
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Stock Status
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