029 farm boss wont stay running

[keithgkn]

Can you guys please help??. I have a 029 farm boss that will not stay running. I did buy and replace the ignition module but it did not help.

[T Welsh]

keithgkn, Sure no problem your in the right place,we like to play saw doctor. First you will have to be specific,you said will not stay running! does that mean it will start and run and then shut off? tell us what it is doing in as much detail as possible. a engine needs 3 basics to run,compression,fuel/air mixture and timed spark. so start there and check to see if you have these functions. and then get back to us.you said that you bought a new coil for it and that didnt help. Do you have spark? Good luck,let us know. Tim

[keithgkn]

well today i thought i would give it another try but the same old thing keeps happening. I did maybe 5 minutes of cutting and it shut off and does not fire back up. Usually takes 20 minutes or so before it will start again. Yes I do have spark but not sure if it is good enough. Very frustrating. I did take saw to Stihl dealer for repair last week. They told me they cleaned the ignigtion module and also tuned it up. I dont think they even took side cover off because there was still dirt in the torq screws.

[Al_Smith]

Take the covers off and blow the saw dust out of it then .Every so often they get so packed full of gunk they over heat .Strange perhaps but true .

[keithgkn]

thanks Al but in the down time waiting for parts to come i cleaned out the covers and it didnt seem to help

[T Welsh]

keithgkn, Check the spark while its cold,see what it looks like. then fire it up and run it till it dies,pull the plug and compare spark,if any to when it was cold. If no spark,thats the problem. Tim

[keithgkn]

so your saying it might be a faulty plug?

[T Welsh]

keithgkn,I doubt it, sounds like your spark is cutting out after warm up. only way to find out is run it and after it dies check for spark. spark plugs dont just work and then not work and then work again. coils (will) do that. I am not saying you have a bad coil,but you have to check what I asked you to do to give you any better answer, I am trying to figure weather you have a spark issue or a fuel issue. if you have spark after it cuts out,then you have to check and make sure your getting fuel. but until you verify the spark is there after it dies. its any ones guess. Tim

[kenskip1]

Two possible sceneros.One is the gas filter is partially clogged the second is a bad gas tank vent.A bad carburetor diaphragm may also cause this symptom.Check for a kinked gas line also, Ken

[ladylake]

 I had one over here that did the same thing after the owner had it to 2 different dealers, it was just adjusted too lean on the high turning about a cazillon RPM with no load. I adjusted it right and ran 5 tanks through it with no problems then sold it as the owner wanted to trade me even up for a CS400 Echo that I let him use.    Steve

[joe_indi]

Hi,

One of these threads might be of some help
https://forestryforum.com/board/index.php/topic,55746.msg806794.html#msg806794


https://forestryforum.com/board/index.php/topic,55711.msg807665.html#msg807665

[tnwood]

I have had the same problem with mine periodically.  In all instances, a new spark plug fixed the problem.  Not sure why but I wonder if the coil is weak and any wear and tear on the plug just doesn't give it enough spark.  I tend to try the cheap and easy things first.  I had this saw at a repair site for weeks once and they couldn't find anything wrong.  Took it home, changed the plug and it ran for a year before it did it again.  Same fix.

[eiklj]

Use a Bosch WSR6F plug in all Stihls. Other plugs just don't seem to hold up for some reason, no idea why.

Also, make sure the black plastic baffle piece has the "sunshine" facing up, not the "snowflake". I've seen saws run run great 'till they get hot, then not start as they hot soak or even vapor lock if the baffle is letting too much engine heat into the carb/intake area.

Just a couple of thoughts, hope this helps.

je

[markd]

Has anyone checked the pulse line, they do dry out and crack over time and they'll start and run abit then suck air and quit. and like someone else said possibly the vent is plugged. good luck

[Al_Smith]

Another possibility could be the crankshaft seals .What happens is the darned things get hot and loose their ability to seal after running a few minutes then after they sit a spell will start right back up .

A pressure test more times than not will fail  to detect this condition .

Recently I stumbled on to this fact on a couple of MS 200T saws .

It's been kicked around on just about every forum the problems with these little saws and was thought the Zama carbs were the problem .After finding this seal issue I'm more inclined to believe that's the real problem not the carbs in a number of cases .

On flea bay for example there are just oodles of Ms200T and 020T crankcases for sale cheap .For every one of those there's a saw with a ruined top end and usually the cause of that relates directly to bad seals .

[markd]

I'm with you, those air leaks are usually  the problem when nothing else fixes it.

[Al_Smith]

Sometimes they are a mystery to find though .

One gent from Ont tried in desperation to locate the cause and he is literally a genious .He shipped that thing to Ohio where another guy racked his brains .

After trying every trick he knew he finally sealed up the cylinder after removing the engine from the saw and tossed it in a tub full of water with 40 PSI of air on the cylinder .Sure enough clutch side seal .It was undetectable in a cold situation using 12-15 psi which is the standard test pressure .

Fact being I've got a little Poulan in the shed which I souped a few years back but never could get it to run longer than 5 minutes and I did pressure test it .Maybe since this thread popped up it answers that mystery .

[AdkStihl]

check tank vent and also the spark arresting screen.

[Troublermaker]

I had a little polan once that was giving to me cause the owner couldn't keep it running. It would run 10 to 15 min and cut off. I check every thing that you talk about. I put 3 or 4 spark plugs in it. Finely I gave  up and gave it to a buddy of mine. He ran a small engine shop and could get anything running if you gave him enough time. He work on it a week off and on. I stop in to see him one afternoon. He said that he just didn't know what was wrong.  The next day he call me to tell me had fix the saw. He said that he woke up in the middle of the night and it come to him to check the gas cap. When the cap was made it didn't have a vent hole in it. He drill a hole and it work fine.

[kenskip1]

 a bad gas tank vent

I was trying to assist you with your problem.See my previous post if you doubt my intention, Ken

[treeclimercj]

I wonder about this saw because I've used it, my friends have used a brand new one, and other business partners have had and used it on a job; even, had another climber worker across the street on another job try to sell me his farm boss. It's a popular make for some reason it seems, and with all I know is that it makes a few good cuts fast with 55 cc's but heats up and wants to cut out. Supposedly its a home owners saw - maybe give it a break on the heard cutting a bit? ?