Has been a good reliable saw until today...nephew has been using for firewood.just quit running...topped off fuel,good spark.dont see.any scared cylinder wall, couldn't get decent compression reading as of yet...doesn't even hit when put gas directly carb,, inquiring minds need your expertise here.for things to try or do? thanks
How did you check the cylinder? To properly check the cylinder you need to remove the muffler can and have a look through the exhaust port. I've yet to ever see a scared cylinder, but I have seen a few scored cylinders. ;)
Yes andy muffler was removed. not a scratch,looks good.great spark say_what
You say your nephew was using it for firewood. If your nephew is young and inexperienced, he probably isn't aware than when you pinch the bar in a cut, you really shouldn't YANK on the saw to free it. This will rip the intake boot and impulse hose. That's my guessignosis.
But that doesn't solve the low compression issue. How are you testing compression?
If your nephew is anything like my nephew(the one that borrows my stuff and brings them back fuel-less, broken, and dull!), the first thing I'd do is dump the fuel, drain any left in the carb, refuel with fuel YOU'VE mixed, and start 'er up and let the chips fly.
My 310 got brought back last winter not running with the same symptoms. After evacuating all the RED dyed diesel fuel, refueling, and sharpening the chain, it was ready to work again. 8)
Kinda funny how those things work out sometimes. I have 8 nephews and 4 nephew-in-laws. The most destructive and absentminded one is also my favorite. :)
Sorta reminds me of me I guess! :D
nephew is experienced enough..saw wasn't in abind..it just died in a cut...thought was out of fuel,,refueled just nothing...we checked compression with compression gage....adkstihl could you elaborate more on the impulse line you was referring too?its got good spark tried gas in cylinder,,not ahit ...maybe should get a diagram may help...may have to take it to someone more knowlageble than me
Did you try the fuel right through the spark plug hole? Try that instead of through the carb. If it won't even fire that way something bad may be happening. I had a Stihl leaf blower die running at WOT in that fashion, turned out to be a crank bearing failure. Hope it's not the case for you. :(
Yeah, it sounds like it lost compression somehow. Even if the impulse line is broke or the flywheel jumped time it should fire somewhere.
Maybe a dumb ? but what is impulse line and purpose? haven't heard of one before but then never worked on chainsaws other than maintenance. I don't know enough ,,,
Who cares about the reason the engine is dead?! Just get a replacement 390 unit from Baileys. Reseal the whole unit to be on the safe side, implant and be happy about the power upgrade! While you are at it I would replace all the rubber.
Good luck!
7
Quote from: sawthemlogs on February 16, 2014, 11:24:16 AM
Maybe a dumb ? but what is impulse line and purpose? haven't heard of one before but then never worked on chainsaws other than maintenance. I don't know enough ,,,
The impulse line is either a hose or a hole through the manifold that takes pressure from inside the crankcase to the carburetor to make it work.
Quote from: 7sleeper on February 16, 2014, 11:46:24 AM
Who cares about the reason the engine is dead?! Just get a replacement 390 unit from Baileys. Reseal the whole unit to be on the safe side, implant and be happy about the power upgrade! While you are at it I would replace all the rubber.
Good luck!
7
Well after a disassemble located a problem...Big gash in piston and bore,rings stuck...hmmm wondering what got inthere to have caused this.After close examination of spark plug.tip of spark plug was missing..Oh well it happens I guess....sleeper will the 390 upgrade still fit????That sounds like a great option....Thanks for everyones input and advice.....
Quote from: sawthemlogs on February 16, 2014, 02:28:38 PM
Well after a disassemble located a problem...Big gash in piston and bore,rings stuck...hmmm wondering what got inthere to have caused this.After close examination of spark plug.tip of spark plug was missing..Oh well it happens I guess....sleeper will the 390 upgrade still fit????That sounds like a great option....Thanks for everyones input and advice.....
http://www.baileysonline.com/Chainsaws/Chainsaw-Parts/Cylinder-Piston-Ring-Kits/Stihl/NWP-49mm-Short-Block-Cylinder-for-Stihl-Chainsaws-029-039-MS290-MS310-MS390.axd (http://www.baileysonline.com/Chainsaws/Chainsaw-Parts/Cylinder-Piston-Ring-Kits/Stihl/NWP-49mm-Short-Block-Cylinder-for-Stihl-Chainsaws-029-039-MS290-MS310-MS390.axd)
There are a few threads on the net about how to be sure that everything is tight and sound. So after ordering one of the engines be sure to follow the instructions to guarentee that you have a long time benefit from your investment.
7
Quote from: sawthemlogs on February 16, 2014, 02:28:38 PM
Well after a disassemble located a problem...Big gash in piston and bore,rings stuck...hmmm wondering what got inthere to have caused this.After close examination of spark plug.tip of spark plug was missing..Oh well it happens I guess....sleeper will the 390 upgrade still fit????That sounds like a great option....Thanks for everyones input and advice.....
Yes it will
(https://forestryforum.com/gallery/albums/userpics/34433/DSC_7557.JPG)
(https://forestryforum.com/gallery/albums/userpics/34433/IMAG0038a.jpg)
Make sure you find the missing piece.
He doesn't need to. If he goes with the 390 kit, it's the whole engine.
Quote from: AKDoug on February 17, 2014, 01:19:26 AM
He doesn't need to. If he goes with the 390 kit, it's the whole engine.
That's right. I just did a MS290 last week, don't know what I was thinking.
Since it's toast why not tear it down anyway and have a look?