I bought a Stihl MS-290 "Farm Boss" from my brother a while back. Saw has less than 15 hours on it. It starts and runs great... for about 2-3 minutes of cutting, then bogs down and dies. It'll refuse to start unless it sits for a minute or 2, then it'll fire right up and run for another minute or so before it repeats this process.

Now if I start it and just let it idle, it'll run till it runs out of gas. Or if I run the hell out of it WITHOUT actually putting a load on it (i.e. cutting something) it'll go till it runs out of gas. Only with a load on it does it act up.

It has a new gas line, spark plug, air filter and the carb has been cleaned and properly adjusted.

Any ideas?

 

I was going to guess a carb rebuild but im no expert

 

classic signs of a bad coil

 

1. Fuel screen, either on the carb or on a pickup in the tank.

2. Coil pack.

3. Check your spark plug gap.


Does it do better on a half load than a full load, or does any load at all on the chain make it die?

What size bar are you running?

Is it burbling at WOT with no load on it?

 

Running an 18" bar. No burbling at no-load WOT. Seems like most any load will kill it within a few minutes. Can't comment or rather a full load kills it quicker though. When it started this crap, one of the 1st things I changed was the fuel line and in-tank pickup. New spark plug too but I honestly don't remember what I gapped it to. I took it to the Stihl dealer last fall. They pulled the carb off and cleaned & adjusted it. They ran a couple tanks through it at idle and it ran fine. Took it home and started cutting and it quit within 3 minutes. Called and told them. They offered to look at it again but admitted they had no way to load it on the bench. Today was the first time I'd started it since last fall to listen for the "burbling"! LOL

 

as stated above sounds like coil to me.

 

I didn't know if these ran coils or mags or just how they worked. I've had coils on old trucks and tractors that would crap out when they got hot then run fine after they cooled off. Guess a saw would act the same.

 

Interesting that a saw shop can't load a saw...every one around here has logs out back they cut because without properly loading one in wood a guy never really knows if they did their job correctly...

A saw should "burble" a little bit when running....kinda like "wawawawawawawawawawa" instead of just "waaaaaaaaaaaaaaaaaaaa"

If the carb is set too lean they won't "burble" and you'll end up with a saw that runs good out of the wood, like free reving, but when you bury the chain it will bog down and die...not getting enough gas basically. Too lean is really, really bad on a chainsaw for a variety of reasons.

There are little red limiter caps on most of the newer MS290 carb mixture screws that can modify/hamper normal adjustments...does your carb have them?


The MS290 has a coil...and if the problems started before anything was done to the carb, that could be the place to start. When it dies, pull the plug wire off and check for spark.

Here is a link to the Stihl manual for that saw:
http://www.stihlusa.com/stihl_owners...390_manual.pdf

 

Cool. Thanks Mr. M. No caps on adjustment screws. This saw was bought by my brother in 2004. I'll take it out in a day or 2 to play with it some more. Gotta wait for the rain to stop first. Got around 2" inches yesterday and it's still not done yet. Calling for clearing this afternoon but I don't think anyone told the rain that!


I've actually been thinking of upgrading this saw anyway. I don't cut a lot... usually 7-10 cords a season. But my in-laws just had 55 acres timbered a few weeks ago and there's more wood sitting back there now than I can cut in 5 years.

There's nothing back there that can't be managed with a 18-20 inch bar, so I don't need a BIGGER saw. Just one maybe a bit lighter and more robust without giving up performance. I'm looking pretty hard at a Stihl 261. Nearly identical hp rating as the 290 (3.75 vs. 3.8) but almost 1.5 lbs lighter. Plus it's a "Professional" model, which I guess justifies the $560.00 price tag. Any experience with them?

 

I borrowed my brother's MS250 to buck up a bunch of firewood. It did the same thing. I followed the instructions in the owner's manual by adjusting the screws and got it working perfectly.