Fixing a Chainsaw

Continuing my DIY streak of buying broken stuff on ebay and fixing it – last weeks purchase was a craftsman gasoline powered chainsaw. Total price? $30.

Stuff I generally look for on ebay when I’m buying something used: Does it have all it’s parts? Does it run? Does it look abused? The number one killer of two strokes by far is running straight gas in them. This causes the rings to fail and whatnot and you end up with a motor with no power if you can get it to run at all. The second biggest killer is carbon buildup. Fortunately carbon just requires cleaning.

The chainsaw was the latter. It was listed as “starts but won’t run”. You’ve got two options basically for fixing this condition – run straight gas (see original paragraph) or clean the carbon out. Or check the air filter! Oh, there’s no air filter on a chainsaw – this is probably where all the carbon comes from. Sawdust. Being sucked straight into the carb. WHO DESIGNS THIS CRAP?

Back on topic – this was a dead easy fix. I keep a ton of WD40 around. It’s really useful, and it also loosens up carbon and gets rust off stuff (sometimes). In a two stroke engine it’s golden because the carbon is usually layers of gunk with oil in between. Find something to thin out that oil and you win. What’s thinner than gasoline? WD40. I had a spare plug. I pulled the old plug (nasty and fouled) and filled the cylinder with WD40. I put the old plug back in and filled the intake with WD40 with a piece of tape over it. Finally, I filled the gas tank with… WD40. I forgot about it until after dinner (about four hours). I considered dumping the WD40 back into the can but after seeing how much gunk it had in it I decided to throw it in the oil disposal bottles.

I didn’t really bother to measure out the proper oil/gas ratio, generally if you put one capfull of oil in the saw and then fill the gas tank and shake it you’ll do OK. Remember – it doesn’t have to be 100%, especially if you’re letting the saw warm up and not chainsawing stuff in the middle of winter, but you can’t run straight gas and expect your gaskets and rings to live forever either. If you’re seeing blue smoke come out the exhaust when you start it, it’s about the right ratio, since this indicates the oil isn’t being completely consumed (and thus some still is in the cylinder to lube it up). For bar oil, bar oil is SAE30, which means any 30 weight oil will work. Note that your car is 10w30, which means it’s 10 weight oil. If you’re going to use automotive oil (and I suggest you do since it’s literally a 10th of the price), then buy a few quarts of honest 30 weight oil. 10w30 simply means it’s 10 weight oil which has 30 weight when it’s cold. Again, unless you’re using the saw in the dead of winter, that oil is 10 weight.

I changed the plug and filled up the tanks with the appropriate fluids. I forgot about the stupid choke and tried starting it several times without the choke and ended up looking up the manual online. Go me – best laid plans and all that. Finally texted my brother and he reminded me the choke lever (which is blue of all things…) needs to be set. Pull the choke, hit it until it tries to run, then push the choke and give it a yank. Yay, it started right up (and put a layer of oil all over everything in my workshop). I let it idle long enough to send my brother a hilarious video of this thing dancing it’s way across the floor and called it a success.

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