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Discussion Starter #1
One of our neighbors owns a 2004 Troy Bilt Lawn Tractor that has been giving them fits this year. First let me tell you the engine information. This one has a 17.5Hp Briggs and stratton engine on it. Engine model number 31C707, Type Number:0154E1,Code Number:04 329ZE.
The Tractor model number is (37120) 13AN689G 17.5HP "42 inch cut.

The problem that we are having is:
The tractor will usually start fine from a cold start, then after using it from anywhere from 10 minutes up to 30 minutes sometimes longer it will just quit.
I have checked all electrical connections and cleaned all as well as used Dielectric grease on all connections. I have ran new grounds to any and all points that a ground is required on. I have changed all safety switches out thinking maybe one of them might be causing the issue to no avail.
I have cleaned the carburetor twice and found nothing there, a new fuel filter changed twice as the ones fro a non fuel pump engine require the 150 micron filter according to Briggs.
I have also changed the fuel line as well.
When this engine starts to quit If I am on it I can bring the throttle all the way down to the idle position and 9 times out of 10 it will keep running. However one has to be fast to do this and disengage the mower deck at the same time.
When it does die, it realy dies and usually will not fire back up for a hour or so.
Anyone have any ideals where the problem may be?
I am so thankful that this mower is not mine. It is only used to mow a single yard and not that big either. The tractor is a 2004 model and has performed well up untll this year. I have changed out the gas as well.
With it being used for the past 5 years now with no problems , does anyone think it might be time for a valve adjustment?
Also can anyone point me to a manual showing the adjustment as I cant seem to locate anything specific to this engine.
I realize this is pretty much a disposable tractor, but it should hold up a few more years as it has been maintained other than this new problem.

Thanks in advance to anyone who cares to share any info or ideals on what might be wrong.
Thanks
Greg
 

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Might be losing the strength to the spark,I hear the ignition coil/modules on many twin cylinder engines and some singles give out when they get hot..it might be yours puts out only a weak spark after it heats up,just enough to run it at idle without a load..

I've had similar issues with a 20 HP Kohler Magnum on my Yard-Man MTD that I haven't pinned down the cause of yet..sometimes I can use it 2 hours straight without a flaw,other times within 10 minutes it stars dying out as you described--mine has good looking spark after it quits though,but squirting gas in the carb doesn't always get it to start again,and it it does,it'll only run briefly before dying again,and wont let you drive it back to the garage!..I dont have 100+ bucks to waste on a coil that might not cure the problem,so for now I just live with it..filling the gas tank full seems to help--sometimes I wonder if its the ethanol in the gas doing it..tank is clean and I put an electric fuel pump on it,with no improvement..frustrating as ****!..
 

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Try the simple thing first. Loosen the cap on the fuel tank to eliminate a clogged vent as a problem. If this is not the answer, and you suspect ignition, regap the spark plug to about .010" and try that. The smaller gap will enable a marginal coil to keep firing. Don't do both at the same time, because if the problem is solved, you won't really know the cause.
 

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I just went through a similar episode with a briggs motor on my tiller. Granted mine is significantly older, but it would run for a few minutes, then shut off and if I jockeyed the throttle around I could usually keep it running a little longer. This was all after I had just rebuilt the carb, pulled the head and cleaned it up, replaced fuel line, filter, plug, and the ignition coil which had about 2” on the insulation on the plug wire burned off, (so I didn’t have a choice). So I figured everything had to be close to “like new”, less the rings and such. Anyway I ended up tearing the carb back down and never found anything, I rechecked everything electrical and fuel and couldn’t find anything. So now I am getting really frustrated, so I back flushed the fuel line, and replaced the filter again, and flushed out the tank. The 2 things I found, a little bit of debris in the tank, not much now, much less than what you would think a filter could handle just fine, but a bit of a leaf that was included in this debris, and I think that could have been interrupting the flow some. The other thing I found was the mower shop had sold me the filter for an engine with a fuel pump and mine did not have one. I do not know the significance of the filter, and like I said I didn’t find much, but after the last teardown of the carb, and flushing of the fuel system it runs perfect and starts on the first pull most of the time.

Personally I don’t think I would be worried about valves, and if you have your air gap for the magneto set at .010” and your plug gap set at .030” you should be fine there. Next time it stalls out on you, check to see if you still have spark.

You only really have 4 things to check, Fuel, Air, Spark and Compression.

Sean
 

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Sounds fuel related to me ....fuel cap plugged,water in fuel tank,debris ....when you reduce the load and idle it down and it continues to run,that's telling me it's starving for fuel under a load....could be a sticky float also ....etanol is an issue with needle floats and seats in four wheelers,causing the same symptoms,the ethanol is causing the needel to stick in the seat ,starving the carb for fuel......adding a little marvel mystery oil to the fuel my straighten up the issue ....my 2 cents,Jim
 

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Discussion Starter #6
Well the darn thing still is acting up. Its really strange that I can go start it most of the time and go out and mow with it fro a few minutes and sometimes for over an hour before it quits.
I have checked the gas cap, did that first thing when it started this problem. I have also replaced the fuel line, cleaned the tank,I have cleaned the carburetor twice and it looks brand new. Also as I stated in my first post all safety switches are working fine,it has a new solenoid, all new grounds which are much better than the factory.

When it dies I still have fuel and I still have spark. That's what is really getting the best of me. The owners usually end up cranking it so much that the battery will go flat. As I also said it will start back sometimes but most of the time it seems like it dont want to work until the next day. Also again there are times if one is fast enougt to get the deck turned off and idle down it will keep running and if I catch it in that time frame I can go right back to full throttle and usually it will keep going fine until it has its next episode.
I have changed the gas out a few times as well and am wandering if maybe ETHANOL may have damaged something in the carburetor.
I have read several article claiming that a lot of small engine shops are seeing a lot more repair work and it turning out to be fuel related. We have gas here with it in it and with out. But who is to truly know what they are buying sometimes. would be nice if they made a Ethanol test kit.

At the rate I'm going my next plan of action may be a stick of dynamite right under the mowing deck. It would most defiantly solve the No Start condition and would not have to ever worry about it not starting again.. :dogrun: :14_6_5: :dogrun: :14_6_5: :dogrun: :14_6_5: :dogrun: :14_6_5:
....
Thanks again to all of your suggestions, I will keep digging away and if you have any more ideal that you care to share, I would really appreciate them.

Thanks again
Greg
 

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It's a usual symptom of a bad ignition coil. They run until it gets hot and dies. Will only start agzin when it gets cool. What's happening is the resistance builds up when it gets hot. Time to change the coil.Part # 795315 cost about $30. Yours is not a twin cylinder which would bring up the problem with valve timing.
 

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I would be intrested also. DID any of the suggestions fix the problem. My first suspect would be the fuel cap vent. The next would be the air filter.I am a fanatic about maintaining filters but I had one become plugged and the symptoms were similar. And me like a dummy,regapped the plug, change fuel filters and fuel lines and cleaned the fuel tank(this was on a JD) which is under the seat pan.
After all that, I was able to get it started and when reassembling the air-filter box,I dropped in the old filter and put on the cover and as I tightened down the screws that secure it IT QUIT. Disassembled the air box it started right up. To finish the story JUST CHECK EVERYTHING.
 
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