The Forestry Forum

General Forestry => Chainsaws => Topic started by: Gary_B on May 26, 2010, 10:06:54 AM

Title: Stihl 021 will not start
Post by: Gary_B on May 26, 2010, 10:06:54 AM
Fellows this one has me stunt.....The saw is getting fuel, and seems to be pretty of fire and will not make a pop. All I did was remove clutch for inspection and replaced sprocket...now the saw will not start..I changed the gas to make sure of no water, I put a teaspoon of fuel in carb, nothing, when I pull the plug it has fuel on it, so with it getting fuel and fire I cannot figure out whats going on, I even pulled the flywheel to check the key, perfect. I think the saw has enough compression..I am going to try and put alittle oil in the cylinder and try starting fluid or carb cleaner. Any ideas out there would be appreciated.
Gary
Title: Re: Stihl 021 will not start
Post by: Gary_B on May 26, 2010, 11:27:46 AM
removed the muffler, the saw started up and ran, removed the muffler guts and put back on wont start, removed muffler again, saw started up....now I am thinking if I might have a compression problem, the piston walls looked alittle suffed up, on the exhaust port.
Title: Re: Stihl 021 will not start
Post by: JohnG28 on May 26, 2010, 07:05:40 PM
With the saw assembled and muffler on, can you hold the saw up by the starter rope, or does the saw slide down?  This is a quick compression test. 
Title: Re: Stihl 021 will not start
Post by: Gary_B on May 26, 2010, 09:10:27 PM
No if you hold the saw up, it does slide down, not fast, but the compression is not strong enough to hold the weight of the saw.
Title: Re: Stihl 021 will not start
Post by: JohnG28 on May 26, 2010, 09:54:48 PM
I think thats a bad sign, you probably have low compression.  Are the rings in good shape?  You said the cylinder looks in rough shape, maybe new rings could get you enough compression to get it running. 
Title: Re: Stihl 021 will not start
Post by: Gary_B on May 26, 2010, 11:08:17 PM
Well the saw is around10 years old and is used primary firewood every season, its a nice light saw for cutting limbs and smaller trees, I use a 28 for larger trees. I have only been able to view thru the openning where the muffler is located. The pistion and rings look a little worn. Might be best to replace piston and rings, I need to tear the saw down and really inspect everything.
Title: Re: Stihl 021 will not start
Post by: JohnG28 on May 26, 2010, 11:25:53 PM
Ya it sucks to have to tear it down just to have a look. Its weird that it will run without the muffler, but not with the gutted muffler though.  It would seem that they would have a pretty similar effect of the engine.
Title: Re: Stihl 021 will not start
Post by: Al_Smith on May 28, 2010, 05:57:19 AM
What has been descibed are the classic symptoms of a completely blown crankshaft oil seal .Although it seems odd it should go by just removing a clutch . ???

If you get one that has blown itself to kingdom come you can pull the rope until you are blue in face and maybe only get a putt every so often .One that is partialy blown might start up cold and run fine for a few minutes then lean out and the saw either run lousey or just die on the vine .

Fact is as I type I have two in my shed with bad seals .Both Macs ,a 10-10 super and a 700 .The very last of the run from the Mac prior to going out of business which surprises me because I've got some 40 years old that have no seal problems .These two are maybe 20 years old give or take and look like new ones . Then come to think of it maybe that's why they look new,bad seals from day one . :D
Title: Re: Stihl 021 will not start
Post by: joe_indi on May 29, 2010, 06:46:32 AM
Gary,
How did you remove that clutch and put it back?
Could you describe how you did that?

Joe
Title: Re: Stihl 021 will not start
Post by: Gary_B on May 29, 2010, 07:18:53 AM
I removed the clip holding the sprocket and needle bearing than in order to break the nut loose, I used a small piece of rope act as a piston stop, I am almost sure I kept it out of the exhaust port and applied pressure and the nut came loose. Removed the clutch, and reinstalled in same manner. I aligned the notch for the oil pump in the clutch housing. The saw is still doing the about the same thing, it will start and run now with the muffler on, but not very well, cannot get it to idle down, without cutting off. Tried adusting carb, but when it does run on its own , the chain continues to move.
Title: Re: Stihl 021 will not start
Post by: Al_Smith on May 29, 2010, 08:12:41 AM
It might be just coincidental and nothing you did caused it.However it appears you have some type of air leak some place . Might not be the seals. Could be the boot . Could be a screwed up carb,stranger things have happened .


I know one guy of whom I won't mention any names but a great mechanic who files fast chains and lives in Ohio .He had one that was giving him fits so he pressurized the engine with air and tossed it in a tub of water .He found the leak . :D