Emery Cloth Really Works???

[mopar969]

Okay, so my co worker overheard me talking about fixing my chainsaws. He gave me his craftsman 40cc 18” wildthing clone. He said it is hardly used but won’t start. Took a look got fuel to piston and spark is good but took muffler off and the thing is scorched. I have read on here you can use emery cloth to clean the piston and cylinder. Does this work? Also I tested the compression and it is 45-50 psi. Will the emery cloth actually fix the torch piston and cylinder or is it a temporary fix? Should I try this or just tell my coworker sorry for the bad news!!

 

[nmurph]

It is a good method for removing aluminum transfer from the cylinder. It can also be used to remove VERY LIGHT scuffs on the piston. It most likely won't resurrect a 40psi piston, but it might save the cylinder with a little work.

 

[mopar969]

So, should I try it to see if it works or am I wasting my time?

 

[watsonr]

Seeing that you can pick them up for around $50 in running condition... for training purposes, I say have at it. But monetarily... she's a loosing proposition.

 

[nmurph]

I wouldn't. I would post in the Swap Meet thread for a used P/C.

 

[JustinM]

Okay, so my co worker overheard me talking about fixing my chainsaws. He gave me his craftsman 40cc 18” wildthing clone. He said it is hardly used but won’t start. Took a look got fuel to piston and spark is good but took muffler off and the thing is scorched. I have read on here you can use emery cloth to clean the piston and cylinder. Does this work? Also I tested the compression and it is 45-50 psi. Will the emery cloth actually fix the torch piston and cylinder or is it a temporary fix? Should I try this or just tell my coworker sorry for the bad news!!

Remember that if a piston is scorched, something had to transfer. Usually its the softer metal on the piston, transferring to the harder cylinder. So yes, in many cases emery cloth (or muriatic acid) will take that transfer off the cylinder & you will be able to re-use it again. If its pitted, then you're most likely out of luck but if the tranfer is on top of the cylinder coating you probably are good. Ive actually only ever had to toss out a handful of cylinders & yet ive replaced dozens and dozens of pistons.

Chances are though the piston wont be salvagable. Remember that if something has transfered to the cylinder then it had to come off of the piston, meaning it cant be fixed with scrubbing. I have no idea what a piston for that saw would cost but I would say that replacing it would only be for the sake of doing so (ie to learn) not because its particularly cost-effective. On a better saw it would absolutely be worth it, but on his saw its most likely not worth the expense considering how much they cost brand-new. You could possibly keep an eye out for one at a garage sale for $10-20 or something...

 

[mopar969]

So,what JustinM is saying is that if the lines of transfer are only on the piston not the cylinder it might be worth a shot?

 

[JustinM]

So,what JustinM is saying is that if the lines of transfer are only on the piston not the cylinder it might be worth a shot?

No, the lines of transfer will be from the piston and therefore transfered onto the cylinder.

Either way the piston is probably toast (especially considering the compression reading you gave) but the cylinder may be salvageable. From a learning standpoint, may be worth replacing the piston if you can find one cheap enough, but if the cylinder is toast its just not going to make any sense to fix.

 

[zogger]

Poulan OEM pistons and cylinders are cheap. Or from sears directly, either one.

Then you need to know why it toasted, just bad gas, or an air leak someplace.

Basically with these various cheap poulans I just accumulate junkers and mix and match to runners. I have bunches of them and when I feel like it, I go through them and make stuff work. Most I will put into one is new fuel lines and filters and air purge bulb if needed. Mostly not ever even carb kits, I take them apart clean them well, put them back together. After fresh mix hits them, let it sit a day or two, then finish starting and adjusting, that seems to rejuvenate most of the gaskets and diaphragm if they aren't torn and just a little dry.

If you really want to make that one work, like I said, whole p/c kits are very inexpensive. Use the real serial number off the saw at sears online, that should give you the correct poulan part numbers, then you can shop from there.