STX38 stalling& hard starting

[ Save This Page ] [ Follow Ups ] [ Post Followup ] [ John Deere Tractors Discussion Forum ] [ FAQ ]

SSB Farm Tractor Parts, Manuals & Antique TractorsAftermarket Farm & Old Antique Tractor PartsTractor Service, Repair & Owners Operators Manual ShopTractor ImplementsTractor SeatsTractor Front End LoadersPedal Toy Tractors Farm Tractors For Sale ClassifiedsAntique Tractors For Sale ClassifiedsTractors Forum - Help & AdviceTractor, Gardening, Mowers & Outdoor Equipment BooksTractor ProductsContact Us
How much is your farm tractor worth? Find resale prices for tractors built from 1939 through today, with complete specifications and serial numbers. Save 15% on our Official Tractor Blue Book sale!

Search This Message Board:

STX38 stalling& hard starting

Brad I have a STX38 lawn tractor that has been giving me problems for about a year. Last summer the tractor would quick sometimes when I was mowing the lawn then start back up in a few minutes and I could finish mowing with no problems. I replaced the fuel filter and sparkplug,but still occasionally had the same problem. This summer it started doing the same thing, but it has gotten more frequent. Now it sometimes will not start at all, but if you try it the next day it will start right up and run fine. I have bypassed the seat switch to see if this is the problem, but it still speratically won't start.If you can get it started you can usaully mow the whole lawn without problems. Everytime I have a problem and get ready to take it to the dealer becuase I think it is finally dead it will startup and run fine thru mowing the whole lawn. I would like to get it fixed, but do not want the dealer just bolting on parts to find the problem. Any suggestions would be appreciated.

Joe Had the same problem and drove me nuts trying to figure it out. Mind would quit after about 20 minutes, and then after starting would run forever. It's the coil. Cost about 40 dollars. Set the pickup/coil gap at .010. Reason it quits and restarts is the magnet is mounted to the flywheel, and the coil is mounted to the cylinder. Coil is already weak, and when the cylinder heats up, the gap is inceased and it quits. Let it sit awhile and the flywheel heats up and the gap goes back to where it was. A weak coil/thermal growth problem.
Tom Sept 30, 2003. I had the same problem. The mower would run for only about five minutes, and then it would just sputter and spit and shut off. If you waited a while, it may or may not start. Usually it would by the next day. This went on for weeks until it just plain would not start at all. There seemed to be no spark. Went to local JD dealer and purchased the 'ignition module'. Some people are calling this the coil, but the actual part description is 'ignition module'. If you remove the shroud, it sits right up against the flywheel, and it is attached to the spark plug wire. The part number is M133019 (for 1996 with black mower deck) and the cost is $42.71. Time to change the part and re-install is under one hour.

Eric This is excellent advice. I was so happy to find this post because the problem mirrored mine exactly. My mower shop couldn't diagnose...never going back there again. Anyway, I was about ready to junk my STX38. I replaced the ignition module Tom mentions above (with a Kohler equivalent for a few bucks less) and it started with the first turn of the key! Even if I have to replace this part annually, it's time and money well spent.
JC Man am I glad I found this site. I just bought a used (1995) STX38 in excellent condition for $600 from a private owner in the community. While driving it the mile or so back to my place, it sputtered and stalled twice. It restarted after a short wait and I continued on. I checked the fuel filter (clean), fuel flow (plenty), flywheel screen and fins (clean and not likely to cause overheating), and replaced the spark plug. It fired right up and I thought that the plug was the culprit. Maiden voyage into the yard lasted 10 minutes before stalling. Now I know it's a heat related problem, but WHAT???... I found this site and I will find a replacement coil ASAP. Thanks!!
Stan I've got the same stalling problem as all the folks here and like them will be buying a new ignition module. What I find most frustrating is that you can't find these solutions from the John Deere website - only from the good folks here. Thanks all.
BL Same problem here as talked about, I picked up the STX38 for 600.00 used and it was fine for a while then right down the tubes, starts when it cools down lasts for a while and dies again.

jahen I called my local JD dealer and they were not aware of any problems killing my spark on my stx-38.My mower would sometimes run normal and then just spit and die. I did noticed that my spark was getting weaker the last couple of years. Replaced the ignition module and she's running fine. Thanks to all.
Gerrel I was given a John Deere STX 38 (Yelow Deck) and it was said to run fine, then stop, and the guy said you had to take the shroud off and mess wqith the coil sometimes.....Long story short, I talked to a John Deere service person, they recommended a the relay and the coil as possible options....I mow weekly now with good results.
STX Reborn!

Dick Hill My STX38 runs for short periods then can not restart for several hours. Replaced fuel filter, not the problem.Local John Deere dealer has advised me to replace the coil as it overheats and kills the motor.Part cost $69 cnd. Will replace it tomorrow.Having visited this web site I am now confident I have the solution.
Terry Allen This is the exact problem I'm having with JD STX38. Is there much to changing out the coil?
joe smathers i was given a stx 38 because owner couldnt make it run i have a couple questions before i tear it down after testing compression and only getting 25# i realized it has some kind of compression release that is opening the exhaust valve slightly on compression stroke is this electrically controled and when does it shut off i am thinking this is the reason it wont start also what is the reason for the cylinoid on carburator
DAVE COURTNEY i have a stx 38 yellow deck i have replaced,coil,spark plug,relay,key switch,fuse,by passed,seatswitch,neautralswitch , ,plus one other switch near battery still no spark,disconnected,wires,from switches and crossed starter with screw driver still no spark,pulled flywheel cleaned stater checked all wires still no spark 12 hours later. help required.
Steen All Thank you so much this was a great information, I just looked up the issue and very fast I found this great solution
Fred I had a similiar issue, until now the mower will not start. I connect it to the battery charger, it will start. I disconnect the charger it dies.
Scott May 09 - Same problem -- thanks for the great tip. Replaced ignition module & everything is working great. About a 60-90 minute repair for an amatuer.

Darrell Sanders Thanks to all involved with this web site...fixed my hard starting 38 last weekend with this same problem. 48 dollars erased my two year headache.
John Klees Thanks everyone involved on this website. I have a John Deere LT 155 with Kohler model CV15S engine. After 10 - 15 minutes mowing the engine backfired and stalled. Had to wait till the engine cooled, start again and good for an other few minutes. Had the problem for the last two months. I purchaced the ignition module part # 12-584-04-S from, $46.07 installed it in aprox. 30 minutes and mowed thelawn for 1 hour with out any problem. I used a business card (.011") to set the space between module and roter.
Jason Williams I replaced my coil/ignition module on my stx38 after reading all of the posts on here about the problem I too was having with it cutting off after 15-20 minutes. Is there any type of timming adjustment that is needed? It won't crank over anymore.
Steve Fisher LT155 with 15 hp Kohler owner here. I had same issues as John Klees. Local big Greene shop not much help. Parts guy did tell me they go thru allot of the ignition modules. Picked one up from them for $50, put it in, and after 3 hours of use, my problem seams to be solved.
Kurt My STX38 was hard starting for years, then yesterday, decided not to start. Seeing the new plug had no spark, I Googled to this site. New ignition module seemed like a good next step. I took the advise and also replace the coil at the same time. Using the tip I read here about setting the coil gap with a business card, BANG...she started with first turn of the key. Thanks everyone for the play by play on fixing hard (and my no) start. One other tip, I used the Kohler website to get part numbers and then priced out the going rate for buying the parts from an internet site. My local dealer had the parts in stock, but wanted to sell at list. A little negotiating saved me $25 total on both parts. I paid more than internet pricing, but picked up the parts same day with no shipping costs.
Kurt last post was tacky..I just realized this post is managed by SSB, a internet parts supplier. Just FYI, usually buy my parts over the internet, but did not have the time this instance. My grass was already 5" tall!
Mark My tracter runs fine for about 5 min then starts acting up stalls out restart it runs 2 min then stalls in at a loss can any one give me some advice?
Iveyclan4 Had same success changing the ignition module on my STX38 bought April 1993 with yellow deck and 12.5 Kohler engine. Paid $54. at local small engine shop but was able to mow lawn this evening. All be warned, I did run into a problem that added several hours to the experience. Broke a bolt taking it off and then broke the not so "Easy out". I recommend using some penetrating oil and wait, then carefully remove bolts. Thanks for the good info. Bruce
Robbin I have an LX255 that began having issues (of course the week I took off work and ordered 15 yards of mulch!) not starting when it was hot, then it began dying about 20 minutes in to mowing. All the websites I could find and my local dealer said the coil. Got one and installed it tonight. Gotta say this was the best site for finding out where it was located! Started the first time. Now to find time to mow...
Matt Man I'm glad I found this site! I have a Kohler CV15S on a Craftsman Tractor Mower (model 917252590). Just this year it ran for about 20 min and then died. Had to wait about an hour for it to cool down and then it would fire right up. Before finding this site, I cleaned the entire carburator and replaced the fuel filter. Still died. Finally replaced the ignition module (12-584-01) and now the thing runs like a bomb. Part was like 35 bucks. Saved me a ton of money. hopefully my post here can help someone else. Thanks again guys!
nick Just got a STX38 for salvage for $50 from JD Dealer. The engine runs strong for 10 minutes then starts sputtering and backfires. I was about to put it in storage for parts for my STX38. Now I think I will give it a $42 chance.
nick UPDATE Gave my 15 year old son son the ignition module/coil to put on the STX 38 I got from the dealer for $50. My son put the module on and the gap was set with a cheap business card. He had in done in less than 30 minutes and the mower is running well. I did not even supervise him. It is a $100 mower for me, $50 for the mower $50 for the module. I took my old mower deck to the welder and he fixed it up. I think it is better than new. Now I have 2 STX 38 mowers. I think I am going back to the dealer as he has one more stx he is willing to sell for 150.
Steve Ok, I may be dealing with 2 seperate issues. These posts sound EXACTLY like the problem I have been having. However, now the problem has switched to where when I try to let out clutch in neutral it immediately kills engine like your turning off. Safety switch on seat has been bypassed and I can't find a clutch switch like on other mowers. Could this ignition module be the fix for both problems or do I have a seperate issue?
Al Had this same exact problem, installed a new ignition module and it still is not working properly. Could it be the wiring or fuel line? Anyone with any suggestions on how to get this mower working again, I'd appreciate it.
Keith Thank you so much to all for this post! I was having the same issue with my 1994 stx38. It would run 20 minutes and die. It would start back up after it was cool. I tried everything to fix it. The ignition module did the trick! $52 and 1 hour later, it ran for 1 hour in 80 degree weather with no trouble. I found a site with info on exactly how to fix it, and the info on this page is 100% correct, even to the business card gap. Make sure you disconnect the battery so the flywheel does not accidentally take your fingers off! See this link. Good luck!
pv Last year I had the same problem. Replaced the coil and everything worked. This year problem is again ordered two coils to be sure, replaced one but was not running well. Saw that the gap was to small and magnet and coil tuched. Mounted second coil engine was running for some minutes. Found out that battery cables were a little bit loose, tighten them engine was running for half hour without problem than stopped running. Tried next day motor is only running for few minutes. So there is another problem than the coil. Would it be possible that the magnet by touching was damaged? Or is there an other problem?? can somebody give advice.
art Intermittent starting, backfires, sometimes will start, sometimes not. No spark at spark plug. Installed new Coil module 12-584-04. Business card for gap clearance. Fired right up runs great. THANKS. PART COST $42 + 5 FOR SHIP/HANDLING.
walter Please please any experts out there? Bought a used stx38, but it wont fire up. It cranks fine, but just wont fire. I changed the battery, starter, and just bought the ignition coil, still did not get a spark. Does the gap really matter? i gaped it with a business card, still no spark. Can anyone please help me? are there any fuses that i need to check? please email me on what i should do next. I would really really appreciate it
Josh I had a similar issue with my STX38. Would run fine for a while then just die if a safety switch was being tripped or something. After screwing with it for a while I figured out I had no spark. I replaced the coil (ignition module) and I've been mowing without any problems since. I gaped the new coil with a playing card. Thanks for the info that led me in the right direction. Replacement was quite easy, took less than a half hour, and that was my first time having the top of the engine off.
tim bender I have the same issue + plus another. Mine would run for 20 minutes and then quit. It wouldn't start for 30 minutes or so. I replaced the ignition coil, fuel filter, rebuilt the carb. I tried running a fuel line without a fuel filter. I made sure the the fuel cap vent was clean.

The other is the throttle cable broke, and what it connect to is very hard to move...


Tim My STX was always a cranky starter. New fuel filter and spark plug helped some. But recently it's stalling on hills. Starts back up after a minute but stalls again. Anyone have this problem?
Josh @DICK:

No, there is no "connection" between the fly wheel and coil. The coil is just gaped very closely to the magnet on the flywheel. I just used a playing card to set my gap. This corrected my problem. The only thing I know of that would cause no spark is the ignition coil, plug, or a safety switch...such as the one beneath the seat.

steve same problem. stx38, mowed saturday for 20 minutes,no prob, shutdown to dump bags & no restart. new plug no spark, replaced ignition module, still no spark. starter good, battery good...just wont turn over and start. what next?
Josh @steve:

Assuming the coil is gaped properly, I would start bypassing safety switches. There is one under the seat that I bypassed while looking for my problem. Also, if the pto switch for the deck is on...or it thinks that it is on, you also will not get any spark.

[ Save This Page ] [ Follow Ups ] [ Post Followup ] [ John Deere Tractors Discussion Forum ] [ FAQ ]
Post a Followup




Email Notification: If you check this box, email will be sent to you whenever someone replies to your message. You must include your email address above to receive this notification.

[ Save This Page ] [ Follow Ups ] [ Post Followup ] [ John Deere Tractors Discussion Forum ] [ FAQ ]


Sign Up For Our Monthly Special Sales!