MS290 problems

[zackman1801]

Well tonight i was finishing up cutting some firewood when all of a sudden my saw shot a short quick burst of sparks out the muffler. Then the saw would not start at all....my question is what happened and whats it going to take to fix it.
thanks
zack

[Rocky_J]

Sounds like it's broke. 
Sparks indicate metal grinding on metal. Perhaps a broken piston ring grinding in between the piston and cylinder?

[Kevin]

Sparks out of the muffler can be common, thus the need for spark arrestors.
You can check for scoring through the exhaust port, compression test etc. and go from there.

[zackman1801]

i would check the exhaust port but as i was removing the screws of the muffler one broke off, and now my only socket small enough has got a nut stuck in it, and i cant for the life of me get it off, ill have to check on the compression though ill probably go and do that now. and to add a final kick in the face the spark plug wire snapped in half....yay now im really loving my decision to try stihl saws......eh.

[Rocky_J]

....yay now im really loving my decision to try stihl saws......eh.

Not a fair shake there, partner. That's like buying a Ford Escort to pull a trailer and then complaining about your decision to try Ford products.

Stihl makes a lot of good saws, the 029/ 290 is their basic homeowner plastic beater saw. It is NOT built for quality or longevity, it is built to hit the $299 price point. If you want a quality saw, then don't buy the basic POS cheap plastic model.

To get the nut out of the socket, set it face down in a bench vise (if you have one) and then use a punch or old phillips screwdriver to stick down through the socket and tap the nut out with a hammer.

[Kevin]

What octane rating is your fuel?

[zackman1801]

im not sure,
[/quote]
Not a fair shake there, partner. That's like buying a Ford Escort to pull a trailer and then complaining about your decision to try Ford products.

Stihl makes a lot of good saws, the 029/ 290 is their basic homeowner plastic beater saw. It is NOT built for quality or longevity, it is built to hit the $299 price point. If you want a quality saw, then don't buy the basic POS cheap plastic model.

To get the nut out of the socket, set it face down in a bench vise (if you have one) and then use a punch or old phillips screwdriver to stick down through the socket and tap the nut out with a hammer.
[/quote]
this isnt the first time ive used a stihl just the first time ive owned one. i have had my husky for twice as long and had no problems. i do agree that its not the best of saws but for less than 10 hours of use under my belt with this thing im sure its supposed to last longer. 

i did get the spark plug off of the saw and it seems to have good compression still. although what does scoring look like? i looked at the cylinder and the exaust port by looking through the plug hole and it seems like at the bottom it looks ok but on top there are slight scratches but not really up and down but more horizontal.

[Rocky_J]

The overwhelming percentage of chainsaw engine failure in the first ten hours of use is from running straight gas with no mix oil (or not enough) in the fuel. Before anyone will believe there's a problem with the saw, first you need to verify your fuel mix. Sorry to be so untrusting but the numbers are not in your favor at this point.

If your fuel mix is good, then it could still be lean seized due to the carb being set too lean.

[Kevin]

You might be experiencing detonation with low octane.

[zackman1801]

The overwhelming percentage of chainsaw engine failure in the first ten hours of use is from running straight gas with no mix oil (or not enough) in the fuel. Before anyone will believe there's a problem with the saw, first you need to verify your fuel mix. Sorry to be so untrusting but the numbers are not in your favor at this point.

If your fuel mix is good, then it could still be lean seized due to the carb being set too lean.

i deffinatly do not use straight gas in my saws. with the gas i used i made sure that i mixed a full un opened bottle of stihl 2 stroke oil with 1 gallon of gas. i used the saw all day with that same gas and refilled 2 times, after the second refueling i brought the saw home and started using it, at that point the saw would bog down and turn off while idling, after restarting it a few times i started pulling the starter cord more and more times before it would run, thinking it was out of fuel i pulled the cord one last time and thats when the sparks came out, the saw was not running when the sparks came out, it happened while i was pulling the starter cord. 
the only thing ive done to the saw so far is adjust the idle, it used to spin the chain at almost full speed while idling, so i turned down the idle setting a bit. it worked fine all day long.  ive been told that the idle does not effect the way the saw runs in full throttle. so technically that would mean i couldent have made the saw run too lean, but is this info correct?

btw what is detonation with low octaine

[ladylake]

Was it sparks or fire coming out of the muffler, If your saw is flooded it might shoot some fire out the muffler. If your seeing diagonal lines in your cylinder thats the cross honeing which is good. Deep vertical lines, then you have trouble. You said you slowed the idle speed down, did you use the low adjuster (side by side with the high adjuster) or the idle speed screw? If you used the low adjuster you might just have it too rich causeing it to load up when idleing, try turning the low jet in some then the speed adjuster out to slow the engine. I see over on the other site you said the plug was dry when you pulled it out, that would throw the above theory out. When it's dieing at idle does it speed up and die (to lean or a gas supply problem) or slow down and die ( to rich and flooding)  Also get a compression tester, that can send you down the right road right away.   Steve

[zackman1801]

when i adjusted the carb i used the bottom most screw. the one thats all alone below the 2 marked L and H.  the saw sits a putters for a minute and then it dies out, but that may be because i adjusted it too far. the saw shot out sparks, similar to what looked like the sparks a fire lets off (like a campfire) they kind of floated for a brief second and went out, not the kind that you see when you rock the chain. Thats why i originally thought that mabey i had some extra carbon build up on the screen. This is because i used a bit too much oil in my mix, i had about a 1/8 of a tank of gas left when i added the rest of the gallon of gas to my gas can but still put in one whole bottle of 2 stroke oil.  the saw smoked some during the day but i figured it was just the extra oil burning out.
as far as a compression tester ill prob bring it to the shop and have him do it, he would probably have one and he would know what all of the numbers mean and what to do with it.

[Kevin]

one whole bottle

Would that be 2.6 oz. ?
That would be 50:1.
I run 40:1, about 3.5 oz. of oil.

[zackman1801]

yes one 2.6 oz bottle.
but i guess i didnt do anything to major, i dumped out the fuel and added newly mixed fuel tonight, poured some in by the spark plug, one pull she started up and cut like a champion. now i need to go and get the broken screw fixed. i didnt run it long, just long enough to make sure that it wasnt going to do the same thing again. now on the agenda for tomorrow i need to get a muffler screw, and get the broken one out of my socket....sounds like fun.

[Rocky_J]

It still sounds like a mild lean seize (as I posted yesterday). Many times if it's only mildly seized it will run again after cooling off. I HIGHLY suggest getting the carb properly adjusted so you don't seize it again, probably for good next time. The fact that you had to turn the idle down also is an indicator that it might be set too lean.

Or you can ignore it and run it until it fries. 

[zackman1801]

im not going to try to adjust the carb, ill take it to the shop. but what are some indicators to know when the saw is running right? how can you tell your not running it too rich or too lean besides the fact that it might stall when idling?

[Rocky_J]

Read this page and listen to the sound clips. I don't know how to explain it to you otherwise. But for me I can tell if a saw is way out of adjustment just by listening and observing how the saw runs and works. Once you burn up a few, you begin to figure it out. 
http://www.madsens1.com/saw%20carb%20tune.htm

[joe_indi]

the saw shot out sparks, similar to what looked like the sparks a fire lets off (like a campfire) they kind of floated for a brief second and went out,

Zack,
The sparks were probably caused by burning cinders of saw dust.Something similar to the wood burning/coal burning trains of the past.
Check your air filter for leaks, saw dust could be entering the engine through it.
Leaning out the L screw would not put seizure marks on the piston, but closing the H screw would.The former would give you a rough  idle while as the latter would cause the engine to overheat under load conditions.

im not going to try to adjust the carb, ill take it to the shop. but what are some indicators to know when the saw is running right? how can you tell your not running it too rich or too lean besides the fact that it might stall when idling?

Is your 290 fairly new or is it old?
If it is not too old, chances are that the carb has limiter caps. In this case  carb  adjustment goof ups are limited.
The screws will turn only a little less than one full turn. Move the L and H screws to the maximum out position

Start up the saw and let it warm up for a minute or so.You might need to have a hand on the throttle or the saw may die in idle.
Turn in the bottom screw (LA) till you get the saw to a fast idle with your hands off the throttle.
Now turn in the L screw till the chain starts to turn at idle.
Back off the LA screw till this stops.
Now rev  up to the maximum, while there, apply the brake and remove your hand from the throttle.(This should be done as a single motion)
When you do this the idle should drop a little bit and then come back to normal.
In case it drops down too far and dies, turn in the LA screw a full turn and back off the L screw a little bit.
Start it up, back off the LA screw if required.Repeat the bit with the brake.

When you have done all that your L screw  setting is completed.

To set your H screw, you will need to have the screwdriver in the H screw slot first.Rev the saw to full throttle, Close down the H screw to the point that the engine speed increases, then back off from that point till the engine starts to 4 stroke (blubber or has a 'puttering' noise).
When you have doen this correctly, the H screw too is set.



**************


Joe

[zackman1801]

no limiter caps, so it must be fairly old. but it seems not to be too used. im not going to try to do this myself, ill have the dealer do it. id rather know it was set correctly than have to wonder and end up burning up the saw because i screwed up or make a mistake.

[beenthere]

joe_indi
Thanks for that screw-setting description...I followed it today, and think the saw is running much better now.

Not sure when L is 'exactly' stopped when "the chain starts to turn at idle"...seems a bit dependent on tightness of chain at that point. Will follow it again tho. 

H was turned back to when it hit the stop, but seemed also to blubber at that point too.

[joe_indi]

no limiter caps, so it must be fairly old.

Zackman, turn in the L and H screws fully (clockwise. not too tight, just to their stops).
Now un-screw both a full turn out.(anti-clockwise)
Turn  the LA screw a couple of turns clockwise, to get a fast idle.
Start the saw, let it warm up.
If the idle is too high turn LA anticlockwise till you get a slow smooth idle.
Now you have set the carb to 'Standard Setting'. This may not be the best setting in terms of performance, but this is the safest setting.
You can use the saw in this mode till you take it to the dealer for fine tuning.
If, in future you feel confident enough for a DIY job, with the carb first set to Standard setting,follow the instructions I had posted earlier.

Not sure when L is 'exactly' stopped when "the chain starts to turn at idle"...seems a bit dependent on tightness of chain at that point.

Beenthere,
The chain should be snug on the bar but not tight. Even if it sags a bit, it doesn't  matter.

H was turned back to when it hit the stop, but seemed also to blubber at that point too.

Make sure the air filter is clean before you do a carb adjustment.Limited air flow could cause a fuel enrichment.
If you find it difficult to set the H screw with the method I posted earlier, try this:
After you have set the L screw, At full throttle slowly turn in the H screw.
The engine speed will increase at a point, note this point.
Turn it in further, if there is no further increase, release the throttle and back off the H screw to the noted point.From here back off the H screw by 5 minutes (similar to how you would set the minute hand of a clock or watch  slower by 5 minutes). That's it.
In case the engine speed increases even beyond the initially noted point, although you could back off 5 minutes from that  point to give you maximum performance, its safer to do the backing off from the initial point.


Joe