free stihl 021 bogs down at wide open throttle

[cheapsaw]

thanks. i ordered a kit off of ebay that says it covers the 021 and alot of other models. the pic has something like 9 different gaskets as well as the screen and needle and lots of other parts. hopefully it will have what i need. seemed like a deal at $8 with free shipping. there were cheaper ones but you had to be sure of the carburetor number, this one said it covered them all.

 

[EngineMan]

Make sure when you clean the carb there are no bits of old gasket left anywhere, make note in how you take things off, and let one know you have the parts.

 

[taxidermist]

so i finally got around to putting the fuel line and filter in today. at first when it was cold it seemed to be running good but as it warmed up, same deal. no power at wide open throttle and if you try to cut any wood it stalls. so at this point im probably looking at a carb rebuild. while i was putting in the fuel line i had the carb off and it appears to be a walbro 215. where is the best place to buy the kit? while i had the carb off i took off the 4 screw cover just to see what it looked like and the diaphragm was intact but had some wrinkles/ stretched looking places in it, is that what a bad one looks like? i have never rebuilt a carb this small, but there is a guy with a video on youtube and it doesnt look too difficult. anything in particular to watch out for?

Before you buy a kit check to see what a new carb cost. I have found that some carbs are 3 to 7 $ more than a carb rebuild kit.

 

[cheapsaw]

@taxidermist:

yeah i paid 8 for the kit, and i saw some carbs for less than 20, but they are all from china and only look sort of like mine. i would be afraid the choke and throttle arms wouldnt fit correctly.i know some chinese knock offs are better than others. their china clone gy6 scooter motors are pretty good for instance. have you or anyone else actually bought one of these cheap chinese carbs and have they worked well?

 

[cheapsaw]

well i got the carb kit today. i cleaned everything real well and matched the gaskets up. got it back together started it up and same thing. i let it run for about 10 minutes and it quit with a loud CLACK. now it wont even pull over by hand. could this be anything but a blown motor? i dont have much money in it but it would still be depressing as i put some time into it. maybe the previous owner ran it on straight gas or something. any thoughts?

 

[EngineMan]

unfortunately it could be the piston or rings if last owner didn't have oil in fuel, if so its best to buy a cylinder head and piston kit, and also bearing(s), if you have never done kind of work best to ask around for cost, but give time other members should be along soon to say what they feel about it.

 

[cheapsaw]

i knowit could be the piston im just wondering if there is even a chance its not. could it be an exploded clutch or pull start malfunction?could it be a problem with the chain brake? on further examination when you shake the saw it sounds like a glass jar full of nails. how do i confirm a blown motor?

 

[EngineMan]

you can take off the chain and bar and then remove the pull starter (cord) with cover, remove plug, now see if you turn over the engine by hand.

 

[cheapsaw]

well i took the pull starter and plug off and its trash. a bunch of black stuff that looked like fine sand came out of the plug hole, im guessing ground up rings. i guess this was probably my problem to begin with, low compression. im not really interested in rebuilding it, although thats probably an option. thanks for everybody's help.

 

[EngineMan]

Sorry to hear about the bad news, if you do go for a rebuild come back and let us know. The black stuff could just be carbon when you the time its worth taking the cylinder head off to have a better look at it you will then if its rings and piston.