Lawn Tractor Engine Running Rough, Missing, Popping, Sputtering / Briggs Engine - FIXED

Picked this up Poulan XT from someone who purchased it in an auction. He did not know any of its history and has not been able to get it running. Will take you through the troubleshooting process and show you how to fix.
Engine Model: 31C707-3346-G1
Poulan Model: 960160024-00 PXT175G42
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#GeneratorRepair #SmallEngineRepair #SmallEngine #DIY #Fixed #Troubleshooting #HowTo

[@TheFlanman10]

I dont know how I found this... but I have to say this guy is like the Bob Ross of small engines. Its soothing to watch him work through these utter turds and make them work again.

[@shanwar9844]

A man who admits a mistake and corrects it...wow. Not only a different kind of person but an amazing teacher! Like we would have known which was the exhaust or intake valve anyway. A true inspiration you are. Please keep doing your thing and sharing. Ty.

[@dporrasxtremeLS3]

Great Comment! Thanks!

[@berylfollington8818]

​@@dporrasxtremeLS3❤very informative

[@MazichMusic]

My tractor with a very similar engine needed a head gasket, so, of course, the valve lash got all messed up. I tried the B&S method with the TSC bumper and couldn't get it to work. Others on YT insisted that was the method. I watched one of your generator videos and I used your technique. My engine sprang to life. Though they recommended using RTV, I did buy a gasket as was supplied OEM. That was in 2019 and the tractor has been running great since with no leaks. Good job! 2023 update: still running strong!

[@bobhipp5146]

and BOOM! You fixed my mower. Same. Exact. Problem. Thank you.

[@jtthill5475]

A few weeks ago I got a "free" mower like that with a "Blown Engine". Lots of loose bolts and missing exhaust studs and battery. Tighten, replace, and add battery and it runs great. Gave it to my neighbor and he cuts my grass. Good deal for me. Thanks for sharing.

[@jcondon1]

Thanks

[@larrymccormick9954]

Great job. As you know all mower owners don't maintain or thoroughly maintaine their mower . They just add gas and mower every time. Thanks for helping others to fix and repair their engine.

[@stevebolaris1076]

My LT1000 (21HP Briggs twin) 20 year old Craftsman turned out to have a coil issue... New part arriving today from Amazon Prime so that I can get back to mowing. Engine ran so rough that I was tempted to buy a new mower at Lowes (2600-3000 dollars). Turns out that one coil to spark plug wire had rubbed and burned through the insulation layers - but enough park was flowing before tear down to fool me into believing that the coil was in tact. After watching this and isolating the coil issue, I will make this Craftsman LT1000 last at least one more year! As you said in your video on the Poulan, sometimes a simple engine tractor can be all that is needed. Mowing my over 2 acres of weeds and native grasses is a battle that the tractor does well for me. Thanks and great work finding that exhaust valve issue and making the repair.

[@kittyhawk9886]

James has the most cut lawn in the neighbourhood!

[@douglaseveland207]

James just wanted to let you know that you are the only person I’ve ever seen to checkout the shear pin by using top dead center. Thanks for the tip!👍🏻

[@bushmaster2936]

are you talking about the flywheel key?

[@douglaseveland207]

@@bushmaster2936 yes

[@JefferyAshmore]

That is way my grandfather taught me, I am 60 now.

[@dannyj5688]

Very thorough on your troubleshooting...covered all bases until you zeroed in on the problem...I like that!!!

[@CaroMik_22]

Excellent thanks 😊

[@Harrison6624]

Studs usually gets loose due to overheating. I always loctite when reinstalling. Good find!

[@brngrofdeth]

You are honestly the best, James. Been binge watching your entire channel. You have shared a plethora of information with all of us. From a automotive tech... love and blessings from Ontario Canada! Just one note... Had my Johnson 35HP at a marina dude to help me get spark. Sure enough it was the power pack. He got it running and told me it runs rough and how far I would like to go with it. It was perfect before the spark issue. Told him that was enough till I get my pennies sorted. Turns out he close gapped one of the spark plugs. Better be careful if you ever take your boat to Norland Marine!

[@canamrider7195]

Amazing that it ran at all, or that the damage wasn't more severe. The past year I have been buying and fixing these older mower. I've doubled and tripled my cost, and have yet to find anything quite as bad as this machine. Great Fix!

[@TheWassel]

Thanks a bunch. I have been struggling with my mower. Your video was exactly what the problem was to a tee. Very grateful for your expertise, just saved me a couple grand for a new mower.

[@jcondon1]

Glad to hear you were able to fix it.

[@johncourtneidge]

Very nice! Remarkable that the valve seat issue didn't create more problems. A real survivor!

[@lawrencepevitts2434]

I have learned so much from you about small engines & diagnosing problems.

[@nickl1682]

Great job . The closed spark plug was the key tip off . Good trouble shooting.

[@brucemcgee2281]

I've had this exact problem twice in the last 10 years! The stud was loose both times!

[@alanrobison3298]

Nice job James! She is purring like a kitten!

[@shyammohabir8283]

You're indeed a skilled mechanic!

[@jeffreyhaynes5774]

Did the same work on my free Murray with a B+S engine,also replaced blown head gasket.Now it have lots of power,it's a keeper.

[@jcondon1]

Very nice

[@davidfrank2824]

You remind me of myself. Where others see something broken we see it as something that can be fixed. Before I give up on something it really has to be broke beyond repair. And then sometimes we get things that someone does not know anything about the peace equipment that they are either selling or giving away. a few years back I found a backpack blower looked brand new in the picture so I called the gentleman immediately. He was less than 10 minutes from my house so I drove straight over. He wanted $25 I talked them down to $20. We got to talking and he said you seem like a really decent person here take this also. He gave me the gas can completely filled with the two-cycle oil already in it. He said he was done with all of that that he was going electric. As soon as I returned home I took the blower to the garage to start working on it immediately seeing that I had to cut the grass that day I could use the backpack blower to clean up. As I'm looking at this thing I realize so on and off switch was in the off position. I stopped taking the air box off and thought to myself this cannot just be this. After putting the switch on the second pull of the starters cord it started up immediately and I was able to use it that day after cutting my grass. Even to this day I still have that in my shed and use it all the time.

[@philliphall5198]

I can’t sleep tell I fix it and I’ve been up very late a few times lolol 😊

[@rawlonstill6590]

should of used the red thread locker because it's good to 450 degrees Faren height, because in the summer that engine gets really hot, but over all you done a great job well done!

[@philliphall5198]

For 20+ years 271 red is all I use on studs period and adjust valves every year and cover gasket are cheap not too clean off rtv

[@Marimbaguy]

My huskavarna riding mower had the same exact issue. I wouldn’t of had a clue that this was the issue and fix. Thanks so much!

[@stephenpidliski8803]

Clear, concise, intuitive, thoughtfully explained, a boo boo or two that's the way we work. I'm electronics, not afraid to pick up a wrench, though. Never did anything on that scale. It's all about troubleshooting and all the rest of that. Well done and thanks.

[@sweetlou5902]

Another great diagnosis and repair!

[@YukonHawk1]

I'm not sure how this video snuck by me. Nice surprise for a Sunday morning. Easy fix too. Glad it worked out.

[@Falconhunter276]

I have exactly the same engine in my hayter, also had identical issues. I used a touch of threadlock on the into the head, it's never happened again. Watching the rest of the video and I see you did the same. The exhaust valve also controls the decompression lever so it was fortunate the engine spun up as freely as it did.

[@johnhouli3450]

Thank you. I just picked up a Yard Machine for a few hundred 2012 very clean. Runs great. Thank you for having a detailed fix.

[@Cre8tvMG]

Thanks. You made it look easy enough that I was brave enough to fix the valves on mine. Way better!!

[@davidkeeton6716]

That mower is virtually the same as a Craftsman DLT 1000, a DLT3000 would be 18.5 hp. I've had a 3000 for since 2003, it still runs and works just fine. I recommend letting it cool completely off after cutting, then rinsing it off with the garden hose after every day of cutting and keeping it as dry as possible between usage. If you can't keep it in a garage, then park it on a small tarp, and then wrap the tarp over it to keep sun, rain whatever off it. Periodically spray some WD40 down the blade engagement cable and take the deck out from under it, maybe every other year to make sure the moving pulley assemblies are moving like they should and the blade spindles are not getting worn and wobbly. Sharpen and balance the blades at least once a year. Change oil one a year on a small yard, two times or more a year on a big yard. Should last a long time.

[@bobsoft]

*For this motor:* Valve Clearance - Intake .003 - .005 in. (.08 - .13 mm) Valve Clearance - Exhaust .005 - .007 in. (.13 - .18 mm) Spark Plug Gap .030 in. (.76 mm) Armature Air Gap .010 - .014 in. (.25 - .36 mm Rocker Cover 60 lb-in. (7 Nm) Cylinder Head 220 lb-in. (25 Nm)

[@philliphall5198]

Thanks for information

[@philliphall5198]

I set at a sung 4 or tight 3 on them Has work great for 20 years But I use 271 red on studs and never had one come loose yet I don’t use rtv because I know in a year the valves need adjustment

[@gwaynewilcox2702]

I knew you were going to cut the grass. you are a great guy. Make Friends!

[@williamvaughan1218]

Always check and make sure the plastic pieces on the pushrod guide plate are intact if they are missing the aluminum pushrod will wear and break. also observe the pushrods where they align with the head gasket and if the head gasket is leaking there will be deposits on the pushrod. These engines are bad for head gasket leakage and pushing combustion gasses into the crankcase causing excessive crankcase pressure resulting in oil consumption. Your lucky the deck even sounds good!

[@jcondon1]

The deck did have issues. Did not make a video on that, but the blades were getting hung up and taking about a minute to disengage (fixed now). And there is some vibration, but cannot find what the issue is. Have changed the blades and spindles.

[@awilson8885]

​@@jcondon1Q 2 Q Q 2

[@earlwest7351]

Poo,,

[@nicholaslloyd5623]

Never thought of adding a fuel shutoff there before the filter... may have to do that!

[@ronaldlincoln2935]

I caught that myself...the dimwit previous owner on my Craftsman has the shut off post filter...makes for a fine mess every time I switch it out.

[@bertgrau3934]

I enjoy working on the OHV engines, to me they are fun. I had a power washer the intake valve guide moved towards the valve head holding the valve open, no compression. A friend has a machine shop and he fixed it for me. Removed the valve guide, knurled it heated the head drove the guide back in did a valve job on the valves, an actual valve job not Lap the valves. It runs great now.

[@brianstaude2783]

More ideas on how simple these are to fix & maintain. Thanx.

[@dar7771]

Nice. You were born to do this type thing. Thanks for sharing.

[@lewiemcneely9143]

Yessir, start them out early mowing. I was mowing ours before I could even start a mower and I was thinking valve problem when I saw the plug. Good fix and God Bless!

[@cstoryusmc]

i own a briggs equipped poulan and its been popping and banging. i might dig in and take a look at the top end. thanks for the insight. great vid as always.

[@aboveaveragejoe6291]

Most of the time you have to go through a lot of crap, you deserve that easy fix!I have a Troy Bilt, same engine and everything, it's a great machine!

[@canamrider7195]

My thanks to you. Turns out both intake and exhaust valve rods were bent on the left cylinder. The exhaust rod was completely off its mounts. I took a rubber mallet and straightened them out, reinstalled, and adjusted to specs. The mower started up quickly and now runs smoothly. My $300 junk purchase is soon going up for sale. I expect it will sell for $1000, as nothing runs like a Deere.

[@willrobbinson]

Got the same motor on similar looking front , will keep this in mind so far it has 120 hrs with reg oil changes ect

[@tomemery3916]

You need to explain about the timing issue . How you set the magnet with the screwdriver. Good video. Thank you

[@andyrichardson338]

Hi James, thank you for this very descriptive, helpful and understandable video . I used it to check my misfiring Husqvarna TS 138 (same tractor as in video), although it proved to be a carb problem I learnt a lot and the valves were a little out and and now spot on. After some carb air intake sprayed into inlet the tractor runs like new. Great job Andy ...United Kingdom

[@jcondon1]

Thanks Andy

[@jesterr7133]

Those Briggs Failtek (Intek) engines are such a pain. I was working on a 17.5, and the valves were so far out of adjustment that it wouldn't even turn over anymore. I didn't know as much about them as I know now, but I didn't even think that valve clearances could get that far off. I only noticed because I took the plug out to use for another machine, and realized that it turned over without a plug in it. That was my first valve adjustment, but it ran perfectly after that. If only I had only realized that the deck was roached before I put all that time into it....... I couldn't find consistent torque specs or valve clearances for that engine either. Most publications I read said it could be between .004 and .007. I set them both at .005, and the engine runs great. I actually have another mower with the same engine that has a problem that is identical to the one this machine had. It was smashing the back end of the plug much like this machine did, and I ruled out valve clearance for some reason. I never got rid of it, so I'm going to go out this weekend and get it running, lol.

[@richardobrien4153]

Thanks!

[@jcondon1]

Thanks Richard!

[@billybsings]

My exact engine and problem. I figured it out before I saw this. Mine is running/cutting but I got the wrong specs for the clearance. I am not idling well. So, tomorrow I will change those specs. Thanks for your thorough explanation.

[@wayned9955]

Hey James, I just wanted to say that your video was excellent, I have a troy-bilt with a 17.5 Briggs and stratton engine and mine had the exact same problem, loose stud and rotator came off, I followed your video and now mine runs like a champ, you have a new subscriber thanks and keep up the great work, Wayne

[@jcondon1]

Sometimes it is an easy fix. Happy you were able to fix it.

[@amoretarot9807]

I bought a 2010 Troybuilt new with the same engine. It's been surging from day 1 but always ran until now. I'm so sick of having people look for the problem every time I get it serviced. After it stalled and won't start, I'm happy to say goodbye and invest in a new one with a different engine. Listening to that surging for 11 years is enough for me.

[@derrickzenner9300]

I like that air filter.

[@HankHillOfficial]

Awesome video. I have been having trouble with diagnosing similar issues on mine and will pull the rocker cover tonight. I usually stick to cars and can pull out a scanner to find the issue and I didn't want to start slapping on parts without a diagnosis. Thank you!

[@TheOcculus]

Paper filters are significantly longer than the inline screen you removed. Those Briggs gravity feed fuel screens come in at least two mesh sizes. Red is 150 micron White is 75 micron.

[@bertgrau3934]

I have a 12.5 horse power murry, Briggs and it was low on power really bad, I checked the valve adjustment and both were over .080 I readjusted to .006 and it ran great it was built in 2005 and its been worked hard. It needs to be rebuilt . Still I was impressed with how much better it ran with just a valve adjustment.

[@tannyrocha9344]

You just figure out my headache and you got a New follower

[@thgrweed45]

Another problem solved. I enjoy you videos. Troubleshoot analyze and repair.

[@KeepItReal1973]

Glad I came across this video. Very well made and very helpful. I thought my problem was with the spark plug wire. But when I took the rocker cover off not only were both rockers loose but the aluminum push rod was bent.

[@mikehill1376]

Well , I just watch my 3rd video on this channel and 100% will keep watching more. I have followed Mustie 1 a long time and learned a great deal . Sometimes I just need answers and not a comely show . Thanks for the excellent videos ..I can see what you are doing ..again 2 thumbs up!

[@jcondon1]

Thanks Mike. I have followed Mustie for a long time and owe him a lot for helping me learn.

[@549BR]

Very informative and educational. Good channel to watch if you have an interest in small engine repair. 😎

[@edhartman2860]

Nice work holmes

[@tonym6920]

Very good video, like your camera work. Much better than most that I’ve seen, at least we can see what you’re doing. Nice diagnostic work also. Thanks., Subscribed. 👍👍. Sounds like a happy riding mower now, lol. 😀

[@jcondon1]

Thanks

[@splash5974]

Very nice! Good fix! When you set the valves, does the valve have to be closed or open? Thank you

[@johnr7416]

Bingo! Thats exactly what happened to my Bolen's yesterday. Fixed it today by this video. Thank you so much! Of course the first bolt I tried to remove from the valve cover snapped off so I've got that to deal with but still, it runs and mows!

[@jcondon1]

Nothing worse then breaking a bolt, but at least it’s running again. Glad I could help.

[@goldiehatman9883]

A lot of folks like to use a power tool to remove bolts, screws and nuts because it's faster but that can snap off a bolt due to suddenly applying torque from the power tool. Better to loosen the bolts slowly manually, then you can switch to a power tool. just my opinion, I hate having to deal with a broken bolt.

[@er1073]

It sounded like a head gasket or stuck valve to me. That was a very quick fix good catch on the clearance for the valves and rods. Thanks for sharing your video with us. Ed

[@adnacraigo6590]

You're a master diagnostician.

[@brucekreitman2169]

I use Formula 88 ( from H.D. ) to clean the engine. Works great. Spray on, wash off.

[@neville3151]

My riding mower is the bomb. It has multi colored lights, dingle balls. diamond tuck red velvet seat and hydraulic lifts

[@tonywright510]

Wow I learned something today I could have swore it was the timing off

[@russellehler6706]

I have the exact same mower "built" by Ariens. Great video!

[@jcondon1]

Thanks 👍

[@jonminer9891]

Hi, James. More good detective work and fine tuning. I would keep the mower as well if I had such a beautiful yard. Thanks for sharing! Stay Healthy!

[@trajonduclos7931]

Love it when you keep one.

[@deangentles4966]

wow james you got lucky ,nice little lawn tractor and video

[@elcomandante9299]

600$ for a used mower is not lucky at all.

[@bobsoft]

Had the same motor and it was backfiring out the exhaust. The exhaust valve rocker was loose like yours. Pulled the head off and found it had dropped an exhaust valve seat. The exhaust valve guide had moved up 3/8" and this stopped the valve from fully opening. Had to press the seat back in and then peen around it to make sure it stays put. After that pressed the valve guide back down and then tack welded the guide inside the exhaust port so it will not move back up again. Lapped the valves and re assembled.

[@lithgowlights859]

I have the same setup here, sold as a Raleigh, but similar to Husquvana sold in Australia. Just a few small differences but thanks for a very informative video

[@beech1120]

I just completed repair on my mower. It had the identical problem as this engine. Followed all the steps, put it back together, and it runs like new.

[@jcondon1]

Nice

[@oliverbreanna789]

Gracias james condon es un video extraordinario me gusto .he aprendido algo . sigue adelante porfa subiendo videos interesantes!!

[@RdrakeIN]

Great help, Thankyou for this.! Do you have a video on how to set the carburetor fuel mix and idle speed. on this type of carb?

[@sadwingsraging3044]

Had the key on a flywheel shear half way through which advanced the timing. When it cranked and got running that thing went insane on rpm! Had to pull the flywheel to figure it out.

[@JefferyAshmore]

I have seen this also.

[@galacticgalaxyonezerone7235]

I was thinking the same thing about the mower even from the beginning it looks nice and new pretty much and a little elbow grease and care goes a long way.

[@garyalensr]

I've alot of your content pop up but never really watched your vids until this one, I have to say I'm so glad I did. Your a great machanic. Now I'm gonna sub your channel and binge watch you.

[@jcondon1]

Thanks Gary

[@StevenEverett7]

Very interesting. I have the identical tractor and engine. It's doing the same thing. The engine runs fine for a few hours then the plug fouls and it runs like crap. I'll have to check and see if that's what's wrong! I've saved this to "watch later" so I'll have a reference!

[@twisted1253]

5:13 that mower is making a sick beat

[@canamrider7195]

I bought a DJ L120 V-Twin Briggs&Stratton a couple of days ago. I was told there was no spark, which is not true. I got it to run, on 1 cylinder as I can tell, and it is backfiring also. Looks like I am following in your path. Valve covers are to come off in the next few days.

[@MrJav69]

Wow what a home run

[@bobwilkinson9894]

great vid James! will keep watching!

[@lorenzodelacruz1887]

Another good show thanks James

[@tonywall8991]

Just had the exact same issue, fixed it ,got once around the yard, and it started playing up again. Haven't looked at it again yet, might be the same problem again or not. I did check the stud but only with my fingers.

[@kaderobertson7052]

Great troubleshooting and thoroughness! Gave me a fresh perspective for my mower issues. Go easy on that RTV! Also that lock tight will change the torque spec! Should be significantly less since it’s now a wet torque.

[@larrykelly2838]

Doc, ya got a deal, unbelievable .

[@jcondon1]

Thanks, been using it all year.

[@jazpanoz4996]

well done on find & solutions as well as score of the ride on,the other guy saw $$ too much to see the problem 😂👍 Fuel bowl of carb. has a fuel shut off,but when they stop working they are expensive to replace,so putting in extra fuel shut off is future proofing it,👍

[@jcondon1]

Thanks 👍

[@williammcilrath905]

sure is nice to get an easy one once in a while good vid Jim bill

[@jcondon1]

Those are always welcome.

[@YeeeeeHaaaaa]

Do the pushrods that holes on both sides where the oil passes through? Unless I’m wrong general vehicle engines have them and you blow air out through them because that’s where oil passes through. Just wondering. Anyhow, awesome video and that was a great touch with you showing us how it mowed at the end. This is a true KZbin video!! Keep it up 👍👍👍

[@dporrasxtremeLS3]

You make learning FUN! and Interesting! Subscribed!

[@MrRenoman2011]

Great job James this is a great video

[@tobiasx5650]

Thank you! Saved me from buying a new one

[@hrgage6307]

This man joes nice work.

[@trudyburns86]

good video i learned a good lesson today, thanks Lewis

[@robnystrom5690]

Thanks bro my john deer 21 hp over head valve ,this was a loose stud just like yours my rotater was off too .blessings to u.thanks

[@stevefrench7015]

That part on the valve stem is called a lash cap.

[@gregfisher216]

I really like that you used a torque wrench to tighten to the proper spec as close as you could . This get it snug or pretty tight is silly!