Medium
30-60 minutes
This is an OEM replacement part and is sold individually.
The purpose of this spark plug is to deliver an electric current from an ignition system to the combustion chamber of a gas fueled engine, igniting the air fuel mixture by the spark.
Over time a Spark Plug will become fouled because the air/fuel ratio may be set wrong, worn piston rings, carbon build up, and other factors.
It is best to replace a dirty spark plug, rather than trying to clean it.
It is important to gap your spark plug according to the owners manual of your product.
Plug-spark 491055T
OEM part for: Briggs & Stratton, Briggs & Stratton Engines
Part Number: 491055T
$5.95
In Stock
Ships within 1 business day 
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Product Description ?
- Classification: Part
- Weight: 0.05 lbs.
- Shipping: Ships Worldwide
Frequently Purchased Together ?
Compatibility
This Plug-spark will fit the following 12046 machines. Confirm this part works with your model, and view the detailed model diagrams and repair help we have to offer.
Displaying 20 of 12046 matching models.
Briggs & Stratton Engines
Show More Compatible Models12046 total model matches. Try the above search to narrow your results.
This is the official OEM part for the following brands:
- Briggs & Stratton Engines
- Husqvarna
- Lawn Boy
- Toro
- Vanguard - Briggs & Stratton
This item works with the following types of products:
- Engine
- Generator
- Lawn Mower
- Lawn Tractor
- Pressure Washer
This part replaces obsolete part #: 491055S ((Rc12yc - Resistor)), 594056 ((Resistor)), 4217, 491055s, 491055, 72347GS, 72347
Repair Videos ?
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Plug-spark
Customer Part Reviews ?
Average Rating (out of 5):
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Easy Peasy
A friend brought his lawnmower to me for repair as it would not start. Installed new plug, carb and air filter and the machine started with one pull of the starter cord!
Sharon -
July 28, 2023
Verified Purchase
Hard to find part
I was pleased that your company handles parts that most stores discontinued. Fast shipping totally pleased with your service.
Guest -
June 22, 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
Good Service
Good products at a good price. If need help the phone service is very helpful.
Guest -
January 5, 2023
Verified Purchase
easy repair
parts were as ordered. great fit. Mower running like new...
Guest -
November 26, 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
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
The exact plug number I needed.
Good plug.
Guest -
May 6, 2022
Verified Purchase
Needed part
Works great
Guest -
June 22, 2021
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
Questions & Answers ?
Our customer Service team is at the ready daily to answer your part and product questions.
Ask our Team
We have a dedicated staff with decades of collective experience in helping customers just like you purchase parts to repair their products.
Does this fit my product?Questions & Answers for Plug-spark
What are the exact specs for this plug. Can I use a Champion 71ECO/RC12YC as a replacement for my Briggs and Stratton lawnower?
Mary
for model number 491055t spark plug
asked on 2023-03-18
Hi Mary,
Thank you for your question. The spark plug measures approximately 3 inches long by 3/4 inches wide. A Champion RC12YC would be a replacement for it. Part number RC12YC has been updated by the manufacturer to part number 71G. If you would like to place an order for it, please call our customer service line and anyone will be happy to assist you. We look forward to hearing from you!
eReplacementParts Team March 18, 2023
Will a BPR5ES or a BPR6ES spark plug work for the above model which is the better one to replace with?
Arthur
for model number 104M020005F1
asked on 2022-08-12
Hi Arthur,
Thank you for your question. The part number listed under your model number for the spark plug is 491055T. It is a BCPR5ES spark plug. If you need help placing an order for it, customer service is open 7 days a week and anyone will be happy to assist you. Please feel free to give us a call. We look forward to hearing from you!
eReplacementParts Team August 12, 2022
My operators manual lists engine parts by Model 80000, 90000, 093J00 and 100000. I can't figure out which one I have by the code on the engine.
Allen
for model number 104M02-0223-F1
asked on 2022-06-22
Hello Allen, Thank you for contacting us. We have researched the model you have provided and have found the part you are looking for is Part Number: 491055T. If you need help placing an order, customer service is open 7 days a week. Please feel free to give us a call. We look forward to hearing from you!
eReplacementParts Team June 22, 2022
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.
Lawn tractor would not start, no spark at plug
Michael - September 10, 2017
👍 6 of 6 people found this instruction helpful
Tool Type
Lawn Tractor
Difficulty
Easy
Time
15-30 minutes
Tools Used
Socket set, Wrench Set
Parts Used
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.
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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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 - September 24, 2016
👍 7 of 8 people found this instruction helpful
Tool Type
Generator
Difficulty
Easy
Time
1-2 hours
Tools Used
Screwdriver, Socket set, Wrench Set
Parts Used
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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Intake push rod bent
Harold - May 15, 2018
👍 2 of 2 people found this instruction helpful
Tool Type
Lawn Tractor
Difficulty
Medium
Time
1-2 hours
Tools Used
Screwdriver, Socket set, Wrench Set, Nutdriver, Feeler gage, spark plug gap tool
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 problem 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.
It was pretty simple after I determined that my problem 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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Wouldn't start.
Richard - May 15, 2020
Tool Type
Engine
Difficulty
Medium
Time
30-60 minutes
Tools Used
Pliers, Socket set, Wrench Set, Nutdriver
Removed gas tank, carb, springs
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Spring tune-up
Michael - May 5, 2020
Tool Type
Lawn Tractor
Difficulty
Easy
Time
30-60 minutes
Tools Used
Screwdriver, Pliers, Socket set
Replaced air filter,oil filter, fuel filter and plugs. Runs like a top!!
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John Deere D-105 would not start.
Dennis - May 4, 2020
Tool Type
Lawn Tractor
Difficulty
Medium
Time
30-60 minutes
Tools Used
Socket set, Wrench Set, Adjustable Wrench
Parts Used
Changed starter and solenoid then adjust the valves. 🇺🇸
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Water pump was not working or didi not produce high presure.
Roberto - April 14, 2020
Tool Type
Pressure Washer
Difficulty
Medium
Time
30-60 minutes
Tools Used
Socket set, Wrench Set
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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repair of 10,000 generator motor
marvin - October 5, 2019
Tool Type
Generator
Difficulty
Medium
Time
More than 2 hours
Tools Used
Screwdriver, Pliers, Socket set, Wrench Set, Adjustable Wrench
Portable generator had been sitting unused for some time. Disassembled motor components carburetor, gas tank. removed front cover and polished the magnetic flywheel and spark plug coils. disassembled the carburetor and cleaned installed new flow seat. replaced all tubing and installed new fuel pump. started and adjusted fuel settings. unit runs and charges as designed.
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A service repair company removed the cover from the engine, and left it exposed in the elements for over 7 months.
Tony - July 25, 2019
Tool Type
Engine
Difficulty
Easy
Time
15-30 minutes
Tools Used
Screwdriver, Socket set, Wrench Set
Parts Used
Replacing damaged components, one at a time. Troubleshooting components to confirm damage, and ordering available parts through eReplacements.
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Oil seal leaking, needs a tune-up.
Barry - April 26, 2019
Tool Type
Lawn Tractor
Difficulty
Medium
Time
1-2 hours
Tools Used
Screwdriver, Pliers, Socket set, Wrench Set
Drained oil, removed fuel line from motor, disconnected throttle cable and starter cable, removed motor from tractor.Put motor on the bench replaced lower oil seal and sparkplugs replaced oil filter. Reinstalled motor on tractor replaced fuel filter reinstalled fuel line, throttle and starter cables, replaced air filter, filled with oil start and check for leaks.
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OEM stands for Original Equipment Manufacturer and means the part you’re buying is sourced directly from the manufacturer who made your product. At eReplacementParts, we sell only genuine OEM parts, guaranteeing the part you’re purchasing is of better design and of higher quality than aftermarket parts.
Learn MoreOur product descriptions are a combination of data sourced directly from the manufacturers who made your product as well as content researched and curated by our content & customer service teams. This content is edited and reviewed internally before being made public to customers.
Our customer service team are at the ready daily to answer your part and product questions. We have a dedicated staff with decades of collective experience in helping customers just like you purchase parts to repair their products.
All our part reviews are solicited directly from other customers who have purchased this exact part. While we moderate these reviews for profanity, offensive language or personally identifiable information, these reviews are posted exactly as submitted and no alterations are made by our team.
All our customer repair instructions are solicited directly from other customers just like you who have purchased and replaced this exact part. While we moderate these reviews for profanity, offensive language or personally identifiable information, these reviews are posted exactly as submitted and no alterations are made by our team.
Based on data from past customer purchasing behaviors, these parts are most commonly purchased together along with the part you are viewing. These parts may be necessary or helpful to replace to complete your current repair.
All our installation videos are created and produced in collaboration with our in-house repair technician, Mark Sodja, who has helped millions of eReplacementParts customers over the last 13 years repair their products. Mark has years of experience in selling and repairing both commercial and residential products with a specialty in gas-powered equipment.
This data is collected from customers who submitted a repair instruction after replacing this exact part. Customers can rate how easy the repair was to complete and how long it took. We aggregate this data to provide a repair rating that allows customers to quickly determine the difficulty and time needed to perform their own repair.
