How to Tell if a Spark Plug is Bad

This video explains how to tell if a spark plug has gone bad. If you enjoy, hit the LIKE button, COMMENT and SUBSCRIBE

[@bikemannc]

Totally agree with you..but good to understand how to test if good or bad..Thanks again for keeping it simple.

[@josephwoehlerii2855]

Thanks for sharing your experience and knowledge Mr. Pender none of us were born with the answers and some just fake it to take our money. Your effort is a cut above.

[@BrucesShop]

Thanks a lot.

[@Lastdayofwork]

Thanks Bruce for that tip, been a mechanic for a long time and never heard of that.. ie: spark plug ohm test. Appreciate, I'm never too old to learn something.!!

[@BrucesShop]

Michael Noel No thank you

[@BrucesShop]

Michael Noel As I mentioned below to remove any confusion. no--- I want to say thank you for replying to my video. I have more electrical experience in my life which I have brought into my mechanical knowledge.Bruce

[@juriedekock6154]

You can only test a spark plug with the plug gap under max compression of the engine say 180lb/sq inch; The spark must overcome the densly compressed air !!

[@lmalino695]

Good rant. Years ago I read that spark plugs on magneto systems almost never wear out. Most of mine (not auto) are original; 30 - 40 years old.

[@BrucesShop]

+L Malino Thanks!!!

[@TheOzthewiz]

@@bacilluscereus1299 The R-type of spark plug is there for ONE thing.... to cut down the amount of current flow thru the plug which reduces the EMI that interferes with wireless devices. If the plug needs regapping, the gap has widened because of erosion (?)

[@robertworkman5620]

Your video identified my problem today. Electrode looked good and gap was ok but plug was leaking voltage to ground. I learned something new today. A big thanks to you.

[@BrucesShop]

That is so cool. I use my meter once a week at least.

[@tonyy5482]

You're right. I've been mowing lawns on and off for 40 years and have never changed a sparkplug on a mower, strimmer (US: weedwacker) or chainsaw. The mower/strimmer/chainsaws rust out or fall apart before the plug needs changing. Fuel filters on the other hand often need changing. Pull cords & recoil starters too. Carb/diaphragm occasionally. I have a multi-meter so I'll try this, my mower is not starting as well as it used to - although I expect it is a fuel related rather than electrical. Thanks Bruce ;)

[@BrucesShop]

I had an old tecumseh mower for 25 years and I have a double lot and never put a spark plug in it. You are right.

[@scottvan1898]

You one of the lucky one, Last summer has replaced a coil of the Stihil Fs 90 , that only used less than twice Years ago, (because it too heavy, my sister put it away, get the electric. ) give it to me last year , installed a new coil & a new plug, start like a charm, last month it’s dead after 15 minutes run , installing a new plug ,it start up in first stroke. ? ? ? 😇😰

[@jkajfes]

kool... watched your video, then checked my generators plug, bought a new one, installed... gens running normal again... so thanks for your vid.

[@BrucesShop]

+John Kajfes Good for you. Thanks for watching.

[@mitchellr.edwards381]

I tried to make the day without learning something new today.And you just ruined that.Lol but i love your vid and well explained.Thanks man.

[@tedfelsberg5322]

So glad you typed in the word “conductivity”. It made so much more sense after that, instead of calling it resistance.

[@BrucesShop]

I understand. The ability to conduct. I worked in the "FIELD" LOL

[@kevinscott9513]

Tested the plug, it was bad. Thanks, good video.Up and running again.

[@BrucesShop]

I find it amazing that 2meg ohms would short out a plug but t is thousands of volts in the high voltage spike.

[@snickerstorino]

great information, i try to tell my customers when they bring me one for a tune up that i can throw the plug at it but its not always necessary and they usually opt to replace it anyway even if its good. i never thought to ohm these out, i always just wire the bail and pull the cord to check spark on the block with the plug pulled. this looks much easier, another great video. thanks for sharing

[@BrucesShop]

Thanks for your comment.

[@CentralRecording]

True. I run mowers weed wackers, dirt bikes, outboards, cars, 2 and 4 stroke bikes. In the past 20 years I've never had to change plugs. I give them a clean, gap them, test them and re-install. Good as new! Thanks heaps for the video.

[@BrucesShop]

Some folks don't like this video but I am happy you agree. Just think of a car that goes 80,000 miles on a set of plugs.

[@alstevens44]

Nice technique, I will check my spark plug next time thanks for your videos

[@joesanchez4895]

I 💯 percent agree with you. I thank you for your video. You taught me a simple way to check a plug. I usually let it run until the engine dies then replace it. Now I have a way to verify it’s bad. Thank you so much!!

[@BrucesShop]

THANK YOU. I have had some push back on this video, but anyone with some electrical knowledge gets it. Thanks again.

[@andybecker2693]

I totally agree with you. In 40 years of owning power equipment I have only had to buy maybe 5 plugs. It’s just like the 3000 mile oil change, totally ridiculous nowadays.

[@BrucesShop]

Thanks Andy

[@sixtyfiveford]

Nice tutorial, I 100% agree with your rant on people replacing plugs for no reason. I find maybe 1 in a100 or less machines actually need a new plug, and that's with all the machinery I service. Most are just dirty or carbon fouled. A quick heat up of the electrode with a blow torch and they are like new. I made a video on just cleaning these things.

[@BrucesShop]

Yes that high resistance between the electrode and ground is like a short to 13000 volts. but not many plugs get to that point. most are just fouled with carbon on the outside

[@MowersNBlowers]

Me too... I've worked on over 200 machines...I've bought maybe 12 spark plugs in my life. Wired brush the crap off. I agree with Bruce.

[@roymg]

@@BrucesShop I keep all of my replaced plugs for use as swap outs.

[@rayburnett3253]

I do they same thing ,except I don't have a torch to clean my plugs. I wire brush them until they look new again. A lot of people don't even know how to repair a lawnmower

[@homebuiltindoorplane]

What a great video, perfectly done. Thank you so much for your valuable information! Have a great day!

[@amberfarmer5227]

homebuiltindoorplane ii

[@THOMMGB]

Thanks for keeping it simple. I'm going to check my spark plugs as well. I even have a Fluke model 73 to check them with that I just bought. So far, it's a keeper!

[@BrucesShop]

Good luck! Fluke makes great meters

[@billnatan536]

Thank you for a great video. Sometimes carbon buildup cause that high resistance to ground, clean it with a wire brush and it can be reused.

[@BrucesShop]

You absolutely right. Just measure them again after cleaning. I think on one engine i dropped a piece of wire from the spark plug into the cylinder and wrecked the engine. Always a learning experience.

[@Bohemian-Nilda]

On target with everything you said, my friend!!!! Thank U for a great video!!!

[@BrucesShop]

You should see some of the comments.

[@MrUbiquitousTech]

Hey, thanks for that tip, it never occurred to me to ohm out a spark plug! That's going to be pretty handy. And I agree with your rant! I think it's mostly people that don't understand trying to convince themselves they know about a subject. Mower doesn't start, must be the plug; TV doesn't work, must be the picture tube (Conventional TV obviously); vintage radio doesn't work, must have a bad tube; car won't start, check the oil. etc, etc, etc.

[@BrucesShop]

Right. Thanks for watching

[@eduardomadrigal6732]

Great videos Mr. Pender, happy new year.

[@philfalz01]

thanks bruce i always learn from your videos very helpful

[@dukecrescent]

I con cur with what you feel... thanks for this video!

[@BrucesShop]

+Peter Andolfi You bet. Thanks for watching.

[@dayvid63]

Thanks for getting back to me, I'll check out my plugs, like you showed

[@BrucesShop]

Great

[@Simon67316]

Thanks for the video. Useful.

[@saltwaterwop]

New subscriber,good stuff.. 11 years on my toro 6.5 mower with the original spark plug and still starting and running strong.. Its all about maintenance and good gas habits.

[@BrucesShop]

Yes maintenance is the key. Bruce

[@BrucesShop]

saltwaterwop Thanks for subscribing!!!

[@avery9997]

As a mechanic at a small engine shop I would say go ahead and change the plug. Start with the easiest option first. Obviously this solution (checking to see if the plug is good or bad) is good for people at home, however if you bring it into a shop you can't expect your mechanic to do this. We are working on flat rate and we aren't going to waste the time testing this. My biggest issue with this method is that it leaves lots of room for error and human mistake. But to each his own! Only my personal opinion and so long as your unit runs whatever method works for you is perfect! I enjoy the videos!

[@BrucesShop]

+avery9997 Thanks I am self taught with an electrical background. Thanks for being kind. Everybody should film themselves for a few videos.

[@Tennethums1]

I agree. Cost wise, it makes sense to just replace it. My 4-wheeler suddenly won't start and I'm replacing gas, spark plug and filter just as a default (one at a time to determine where the fault lies). It's only a year old and has never been ridden hard so it can't be anything TOO bad (I hope!). But this video does help to explain just what a spark plug is and does and how you can identify issues. If your problem doesn't lie with the spark plug itself but in the wiring (or worse) at least this can help to narrow down any issues. Thanks for the video, mate!

[@BrucesShop]

+Tennethums1 Yes I am on a tight budget. Thanks for the comment.

[@itsmeagain-cv6lj]

@avery9997 We all know (sadly) that every mechanic (at his own garage) are heavy eater $$$ That's why THIS KIND OF TIME WAISTING is at the hand of every newby who try to repair is thing by himself. (At 18-30$ each plug uhm...) *Try to keep your "secret" of succes in your garage mister The Mechanic ; )

[@oakivil]

Great video! Thank you for helping me fix our lawn mower.

[@BrucesShop]

a little electrical knowledge is great.

[@joshuawilganowski7413]

Awesome, thanks a lot for the video. Very useful.

[@tommagee9415]

Glad to this about spark plug.thanks

[@hugoavila3450]

nothing wrong with being frugal, excellent video helped me out....thx

[@BrucesShop]

+Hugo Avila Well thanks for watching.

[@joes7407]

Omg my father in law and I have been trying to fix my generator for three straight days. This video helped us fix it in the time it took to test the plug and drive to AutoZone. Thank you sir!

[@BrucesShop]

Perfect

[@runechap9145]

Excellent information! Thank you so much for sharing.

[@BrucesShop]

You are so welcome!

[@ebelionavarro4354]

Thanks for the tip. Be watching !

[@BrucesShop]

Right on Thank you for watching.

[@timothywatson9617]

I know a guy that every time something want start . He says it's the plug and that's not true I agree with u 💯

[@Joe_Rebel]

i agree i have an old torro snow blower has its original plug since 1987. god i wish stuff was as good as it used to be.

[@BrucesShop]

Some stuff is better than it used to be. Car only lasted 100,000 miles when I was younger now they go at least 250,000

[@danmills7858]

Thanks for the simple explanation and demonstration! I will confess as one who is guilty of changing spark plugs to correct an ignition issue. I will use this test from now on, and look forward to more videos! Dan

[@BrucesShop]

Thanks Dan. Not everyone gets this video.

[@MrSpot41]

Great vid, very helpful. Thank you.

[@BrucesShop]

Thanks for the comment.

[@kennedysingh3916]

Thank you,you have made my work easier.

[@BrucesShop]

No thank you

[@MrVegasTube]

100% USEFUL!!!!! THANKS!

[@byronbridges213]

E/I. Great video. I've learned something. Thank you

[@BrucesShop]

Thanks a lot sir !!!!

[@Bayoustate2011]

Thanks for the video! It really helped me out.

[@BrucesShop]

You are welcome.

[@alekseyklimets6589]

Thank you very much! Helped me a lot

[@BrucesShop]

Great!!

[@xploitedyouth77]

thank you sir for the video. helped a lot. believe I'm having issues with a spark plug currently on a small engine with only about 10 hours of use. however it's a crummy Chinese knock off spark plug and everything else I've looked into is checking out. good fuel, air cleaner. clean etc so slowly narrowing down the issue to hard to start motor. it's practically new so wiring and such all seems to be fine checking current on them as well. again thank you for the video.

[@BrucesShop]

+Mitchell w You are welcome.

[@Rattletrap2]

Interesting! Thanks very much for this knowledge!

[@BrucesShop]

Glad you enjoyed it!

[@martingriego6800]

Gud info, for alot of people that dont know

[@thangknowa3288]

Very good, thank you. On 2 cylinder engines, after plug cleaning, I swap them around to confirm that any problem is not plug related - might be plug wires, coil pack, or other issues. I note the "Side" with the issue...

[@BrucesShop]

Great tip!

[@TippyPuddles]

I was just cruising the KZbin for information on the air filter to my tiller. It's misfiring and I haven't had it running since last year. I'm no mechanic, I learn as I go. Too poor to afford to pay someone. I was wondering if my spark plug was bad and was going to replace it first. Thanks for this information. I just bought a multi-meter to work on my washer (got that running). I can use it to test the spark plug on the tiller now. Thanks for the information.

[@BrucesShop]

Good for you. Give it a try.

[@berardia4]

Thanks for the tip. I personally have never had to replace plugs unless someone replaced them with the wrong type.

[@MSBsasquatch1960]

Yep, I have never changed a spark plug in any of my small equipment, chain saws, log splitter, roto tiller, lawnmower, etc. Clean, gap check, test and use. 👍

[@BrucesShop]

Exactly Thanks

[@yubastardus]

you are awesome! thank you!

[@stephenison5703]

Thanks for this video 👍

[@BrucesShop]

Thank you for watching.

[@samiranezami2943]

You are So Gentleman. Love From Afghanistan

[@BrucesShop]

Thanks

[@patrickflohe7427]

You make a good point about the meter probes picking up resistance from your body. Keep fingers back on the insulated handles, let the spark plug sit on a non-metallic work bench, or a block of wood if it’s metal.

[@BrucesShop]

You understand. Thank you.

[@kentuckycunctator]

Thank you, sir.

[@59chevt]

Thanks for sharing.

[@marshallborder9089]

Good video , thanks

[@ThePlynn7]

Thank you, this was a huge help in troubleshooting. After testing my spark plug it showed it was bad, bought a new one and my lawn mower fired right up. Crazy, the original plug was less then a year old. I was hesitant to buy a new plug cause the original looked good.

[@BrucesShop]

+ThePlynn7 I have had some that looked so bad and were OK and like you another would look perfect and is toast.

[@travispoppler8023]

I agree, I only replace plug if customer insists on or want top dollar for a unit for sale. Looks good with a fresh plug in if old one looks crusty. Thanks Bruce

[@BrucesShop]

Totally agree

[@wasimedo3877]

Good job 👍

[@scotthoover6689]

Good info!

[@Lovinflyindrones2022]

You seem very very knowledgeable about the mechanics of the machines that comes in your shop as well as the electronics of the machines. Spark plugs , coils etc. I would love to see you do a video or videos if you would on say trouble shooting the electrical aspects of the machines. Example. How to check a coil, spark plugs, safety switches. E t c I would love to learn more about it from my favorite small engine mechanic here on you tube.

[@BrucesShop]

Thanks. I will slow down on the next electrical repair.

[@rmp3648]

Thanks Bruce! I know I am guilty of this habit, but no more!

[@BrucesShop]

Thanks for watching RM P

[@alitiger5554]

great informative video ..Thanks

[@BrucesShop]

Thank you Ali

[@joejava]

Thanks for sharing your video on KZbin I never knew about using an ohms tester. People here my bitch about what you have said but as far as I'm concerned I have learned a lot and I sincerely thank you for it!. Believe it or not I think that doing this will definitely save me money in the long run because I have been spending far to much money on those damn spark plugs for sure!. However since watching your video I now know how to test them spark plugs and I sincerely appreciate your video and for sharing.

[@BrucesShop]

Thanks for the great reply.

[@rudyresendez6572]

Joejava SIRS. YOU ARE ..ABSOLUTELY ...CORRECT...OHMS,RESISTANCE,VOLTAGES..ALL APPLY WHEN TROUBLE SHOOTING...ANY CIRCUIT..(automotive, lawnmowers,lighting circuits- these are ‘DC circuits’)...knowledge is amazing...makes repairs easier and satisfying thank you for sharing...KEEP-ON-WRENCHING..fellow UTUBERS

[@parvizisa]

Awesome. Useful. Thanks

[@BrucesShop]

real human Thanks real human

[@1995RangeRover]

Great video! Thanks so much!

[@BrucesShop]

You are welcome Rover

[@BrucesShop]

Thx for the sub too!!!

[@1995RangeRover]

Anytime Sir! :)

[@daalhoffarm]

very good video, thanks!

[@BrucesShop]

Thanks for watching

[@geojor]

fully agree bruce...

[@krazytrinisteve]

Guilty as charged...awesome vido

[@BrucesShop]

OK

[@puncht37]

Good vid. Most folks don`t have or don`t know how to use an ohm meter but, one doesn`t need a high dollar DVOM to check a plug. A cheaper analog, sweep type works fine. Least now, most can at least remove their plug from their "parts changing" list for a no start.

[@BrucesShop]

Right. I have 4 meters. A good one you saw. @ cheap digital and an old polarity sensitive analog. Thanks

[@SonOfLiberty1984]

Spot on!!! Use your brain instead of simply being a parts changer.... I like it!

[@BrucesShop]

Thank you.

[@ebfromwyoming4118]

great video sir

[@BrucesShop]

Thanks old video

[@BWOUTDOORS]

great video to watch.

[@BrucesShop]

Thanks for the visit

[@theragingcreeper9040]

I have a spark plug from...somewhere around the 1900s- 1940s

[@MrBoldmike]

Very Helpful thx

[@BrucesShop]

+MrBoldmike Thanks Mike

[@majorpayne5289]

👍Totally agree. I find it funny when folks drop off their mower and the very 1st thing they say is they think the spark plug is bad😂😂😂 Most common issue around my neck of the woods is a dirty clogged carburetor. Thx for the video.

[@BrucesShop]

I am sorry .I am getting so any comments from you I don't have time to answer them all. i am doing 200 comments a day now as I have almost 40,000 subscribers. Plus editing and the work in the shop. Sorry buddy

[@majorpayne5289]

@@BrucesShop - Hey man, no worries! I just figure if a good KZbinr puts out good content then the subscribers should do our part by thumbs up & leaving a comment. I’ve heard it helps out a lot. (Algorithms and such) It’s always nice to hear from ya however it’s understood & no reply needed. We’re all here for ya in effort to grow your channel & show appreciation for the video help that you provide. Take er easy my Canadian friend 👍 (Ol KY 🇺🇸 boy here)

[@BrucesShop]

@@majorpayne5289 Thanks for that.

[@ngzcaz]

I have an old Snap on spark plug tester and cleaner. This is a big unit, probably well over a foot high and over a foot in length by another foot deep.To clean you use the silica/sand under air pressure. To test the plug you used just the clean air button to see the plug firing in the unit. It produced varying degrees of compression in the unit. That way you could actually blow out the fire in the plug if the plug was faulty. I used it many times over the years to detect a bad plug which btw wasn't that often. In those days of ignition points you could buy a single plug instead of a whole set..

[@BrucesShop]

That is interesting Thanks a lot.

[@678friedbed]

I get what you mean. I just replaced the spark plugs in a car after the previous owner ran them for 200,000 miles, they worked but the electrodes were pretty much not there.

[@baza7008]

right!.... i'm with you now.... excellent, i couldn't figure out why when i put the spark plug to the engine block why i was getting a spark from the earth (the 'L' shape bend at the bottom of the plug) to the engine block, but no spark between the two contacts in the middle and why the engine wasn't firing up, starting, or running, so me plug must be knackered then because it's leaking if i think i'm right in saying after watching this then....

[@BrucesShop]

Sounds right.

[@baza7008]

yeah changed the spark plug works perfectly fine now, engine starts first time, no problem at all, that's the first time i've ever known a spark plug to ever fail like that, very unusual.so cheers for that.👌👍

[@H.W.H.alshammari]

nice.Thanx

[@curiosity2314]

Looked at a number of videos but it finally started to click here. Ariens Snowtek 20, comes with a LCT 136, worked last year but I needed the electric starter to start it. Would not start this year in prep for winter. It comes with and LCT recommends a Torch F6RTC, well I was getting about 4K electrode to ground but I found when I moved the electrode slightly I got zero ohms, at this point I carefully moved it to the snow blower and wallah Spark! I'm not sure how it is shorting but is is. 50 plus years and never saw a spark plug that would not work. What I saw here is that some do not work. It has to be pretty rare? This one is getting hung on the wall.

[@BrucesShop]

Yes the carbon inside the porcelain gap can conduct but if they are cleaned most of them can be revived as you say. I reuse plugs all the time and have only had a few that are duds.

[@rgruenhaus]

I just replaced the spark plugs on my Ford fusion hybrid after 182k miles! The electrode was worn to a small nub, but the car never showed signs they weren't working. Less vibration after replacing then though! Iridium tips on the new Bosch plugs.

[@BrucesShop]

Thanks for the great story.

[@Lagify229]

Now I completely agree with you on everything but depending on the aspiration of your vehicle (turbocharged or supercharged) will determine how much you should change your spark plugs. My mustang is turbocharged so i have to be spot on with my maintenance and repairs.

[@BrucesShop]

These are lawn mowers.

[@Lagify229]

@@BrucesShop i meant to reply to someone🤦🏽‍♂️

[@danielb.9051]

thank you

[@armyvet4081]

I have never bought a air filter . I use foam packing material. When it gets dirty just was in warm soap and water.

[@adnacraigo6590]

Makes perfect sense to me.

[@BrucesShop]

Thanks. Those that don't understand electricity give me a rough time.

[@benr4643]

Great video! Learned something new I mostly clean them up for a few years then replace. What's your thoughts on Rec gas if you have that up in Canada?

[@BrucesShop]

I am not sure what rec gas is?

[@benr4643]

@@BrucesShop What we call Rec gas is Gas that had no ethanol in it. Which gas that has it has a better chance of going bad from having too much water in it.

[@BrucesShop]

@@benr4643 Yes I can get it. At this point in time but not all over Canada the CO_OP where I buy gas has all 3 grades of fuel 87 91 and 93 have no ethanol in it.

[@dvdfrnzwbr]

This helped me!

[@BrucesShop]

Great!!! You I am happy you could use the info. Bruce

[@pamelasingleton7430]

crank sensor for 2002 saturn l200

[@dh.mowersblowersservicesll4061]

Great video

[@BrucesShop]

Wow this is an older video. Some folks like it and some don't.

[@dh.mowersblowersservicesll4061]

Where do u buy your shop supplies an parts from ?

[@neilwilliams2409]

Bruce when testing the electrode with your ohm meter fine. But mate unless the electrode has a dead short to ground an ohm meter will not pick it up. Really to test between the electrode and ground you need an insulation resistance tester (megga ) which puts a high voltage between the electrode and ground and you will see if there is any breakdown in insulation. Which would not be possible with a continuity tester. The high voltage on the ignition system will find any weakness in the insulation between the electrode strode and ground. But still a good informative video .

[@billybobb7252]

Good one Bruce, Just thinking about your comment on the resister plug and radio interference ? You mentioned the different plugs in use in the US and Canada. So besides that do the non resister plugs give the same performance and last longer?

[@BrucesShop]

I really don't know. Or if it harder on the coils to. I don't know.

[@billybobb7252]

No worries Bruce . Well you know what the say down my end of the swamp .. Whatever you do dont give up your day job .. !

[@BrucesShop]

I don't know. Honestly. They both seem good. there may be some coil differences in life, but i am not a scientist.

[@ghibliinu6616]

Mr. Bruce if interference is not an issue from the spark plugs in my riding mower, is there an advantage to use resistor plug? If I interfere with no one there is no use to resistor plugs is there? Thanks for this interesting video!!

[@BrucesShop]

Resistor plugs were made to reduce radio interference.

[@service1956]

Yes, that is a good way to tell if a spark plug is bad. One "BAD"test that many will do, is that they will remove plug from engine. Attach the high voltage lead to it, and then touch the base of the plug to the ground of the engine while pulling the starting cord and watch for spark at the gap. If they see a spark, they determine that the plug is good. But some times a bad plug will not produce spark when under engine compression!

[@BrucesShop]

+service1956 You are right.

[@jano7642]

The colour of the spark should be blue. Orange colour means bad plug.

[@omchunter6988]

Your badass man

[@omchunter6988]

Yes it is good! This video helped me learn some useful knowledge about plugs and how to expel myths of "plugs bad".

[@schaandonaldson]

Right O. Thanks

[@BrucesShop]

Thanks for watching.

[@kkdonovan3804]

thanks for this video. Now I have a question do all lawn mowers have an oil filter? I have a 22inch toro recycler and cannot find the oil filter???? is this possible

[@2014ultra]

No sir unfortunately all mowers don't have oil filters typically most walk behind small engines don't use them untill you start getting into the bigger industrial versions but itleast you can change your oil often for only around 5 bucks

[@BrucesShop]

daniel hebert Great!!!

[@crippledrider]

Hi Bruce; I agree with you, spark plugs do wear out in a few seasons use, but keeping the engine running properly. is a huge factor. air intake and carb settings very important. Reduce carbon!

[@ronbilton6240]

Spark Plugs if watched, will show little evidence of wear-out... a simple re-gap and clean usually will do, unless your engine is mechanically doing damage to it as in laying on carbon. There are no mechanical units in spark-plugs to wear out.