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Post by rarefish383 on Feb 5, 2019 10:38:32 GMT -5
Starting to work on my C72. Piston is up high enough to block off exhaust. Just filled with 50/50 ATF and Acetone. How long should I let it sit? After draining do you try to turn it with the bolt on the crank? I thought I heard some one put a zerk fitting in a spark plug and pumped grease in. I have an air powered grease gun.
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Post by edju1958 on Feb 5, 2019 11:19:03 GMT -5
I've been told to let it set in the cylinder for at least a week & keep adding new fluid as needed because it may drain down.Also,try to turn the engine over periodically to see if it'll beak loose.I put a nut on the end of the crank & put a socket on it & use a breaker bar.You'll have to secure the engine somehow while trying to break the piston loose.I had an XP-1000 last yr.& I couldn't get the piston past a certain point where it'd bindf up quite tight.I ended up putting a wooden dowel rod in through the plug hole & tapping on the piston head to get it to come out of the cylinder.I've been told by an old-timer that in order to break loose a seized piston that you need to turn the engine in reverse rotation.I didn't have any luck with this method on a Mac D36,it's still seized tight as can be.Good luck Joe. Ed
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Post by rarefish383 on Feb 5, 2019 12:22:02 GMT -5
Thanks Ed, I can see where the reverse rotation may work. Actually, the cylinder on both sides looks pretty clean. We will see.
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Post by rowdy235 on Feb 5, 2019 19:20:07 GMT -5
I'd let it sit at least overnight, maybe several nights. I go by once a day or so and try turning it over, don't apply too much force just wait for it to come loose.
I don't know about the zerk fitting. I'd be more apt to just adapt a Schrader valve and pressurize the ATF/Acetone mix.
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Post by sweepleader on Feb 5, 2019 21:47:46 GMT -5
Don't use air pressure, you can get flying parts that way. The grease thing works as far as moving the piston to the ports, then you are done. I would just soak it for as long as I could stand waiting, trying to turn it backwards maybe once a day. I would not put a large force on it, the crank and rod were not made for that and damage could ensue.
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Post by jbowski on Feb 5, 2019 23:15:10 GMT -5
remove the core of a valve stem, then drill a 5/64" hole through the valve stem cap, use PB blaster/kroil tiny red applicator tube epoxied in valve stem cap. push the valve stem into the spark plug hole and blast it with the aerosol can through the valve stem over the course of several days. occasionally rocking the crankshaft both ways without applying force.
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Post by rarefish383 on Feb 6, 2019 8:44:05 GMT -5
Forgot to mention, I'm a bit of a stickler to following directions, when I read a 50/50 mix of ATF and Acetone. I was thinking how am I going to mix a small amount without ruining some of my wife's cooking stuff. I went in Ace Hardware and asked if they had something I could use to squirt the mixture in the plug hole. They have a 3 pack of different syringes for a buck or so. The middle size fits snug in the top of the ATF bottle, so I withdrew a syringe full of each and mixed it in an old coffee cup. Made the perfect amount to fill the cylinder, and no mess left over to clean up. Put the plug back in and rolled the saw on it's side, made another small batch and filled the exhaust, have it soaking on both ends. If that doesn't break it loose in a week or so I'll try the other methods, Joe.
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Post by blythkd on Feb 6, 2019 21:45:25 GMT -5
Forgot to mention, I'm a bit of a stickler to following directions, when I read a 50/50 mix of ATF and Acetone. I was thinking how am I going to mix a small amount without ruining some of my wife's cooking stuff. I went in Ace Hardware and asked if they had something I could use to squirt the mixture in the plug hole. They have a 3 pack of different syringes for a buck or so. The middle size fits snug in the top of the ATF bottle, so I withdrew a syringe full of each and mixed it in an old coffee cup. Made the perfect amount to fill the cylinder, and no mess left over to clean up. Put the plug back in and rolled the saw on it's side, made another small batch and filled the exhaust, have it soaking on both ends. If that doesn't break it loose in a week or so I'll try the other methods, Joe.That grease gun deal is interesting. If the exhaust port is covered, it'll just push the piston back without applying any pressure to the rotating parts. Nice even pressure across the piston as well. It'll either break it loose or break something! That's what puts tension on the tracks of older dozers. I took the grease cylinder apart on a D6 and it was about 3" diameter. That applies a ton of force to keep that track tight.
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Post by jbowski on Feb 7, 2019 0:40:43 GMT -5
Forgot to mention, I'm a bit of a stickler to following directions, when I read a 50/50 mix of ATF and Acetone. I was thinking how am I going to mix a small amount without ruining some of my wife's cooking stuff. I went in Ace Hardware and asked if they had something I could use to squirt the mixture in the plug hole. They have a 3 pack of different syringes for a buck or so. The middle size fits snug in the top of the ATF bottle, so I withdrew a syringe full of each and mixed it in an old coffee cup. Made the perfect amount to fill the cylinder, and no mess left over to clean up. Put the plug back in and rolled the saw on it's side, made another small batch and filled the exhaust, have it soaking on both ends. If that doesn't break it loose in a week or so I'll try the other methods, Joe. The acetone tends to evaporate so its best to mix as you go anyway.
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Post by rarefish383 on Feb 17, 2019 13:41:08 GMT -5
Ok, got the piston free. The part of the piston that had been stuck up in the cylinder looks like new, The skirt that was visible from the exhaust had a brownish varnish looking crud on it. Took a while of rocking it back and forth to get all the way around. Now it goes around easy up to a little bump where I think the varnish was built up. The more times I spin it around the more the varnish looks like it's coming off. I have a 3/8 inch extension that goes on my DeWalt nut driver. I was going to put that on it and spin it around fast, but just as I picked up the nut driver the battery went dead. I was going to stick the plug on the wire and spin it fast and see if it has spark. Anything wrong with spinning it over with the nut driver?
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Post by sweepleader on Feb 17, 2019 15:37:08 GMT -5
Don't use an impact tool, if it is just a drill motor rigged for driving nuts you are fine. If you use an impact gun, you can easily break stuff and strip threads doing that. My DeWalt impact gun puts out about 200 inch pounds of torque, that is dangerous around saws. I only use it to remove stuff that is stuck, never to turn a saw. A straight motor tool like a drill is fine, the torque is MUCH lower.
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Post by rarefish383 on Feb 17, 2019 18:19:57 GMT -5
Thanks, I have several drills too, I just like the little nut drivers because they have those speed connectors.
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Post by rarefish383 on Feb 18, 2019 11:11:46 GMT -5
Stuck the drill on it and spun it over fast, no spark. I'm trying to decide if I'm going to take this one apart and restore it. It needs a new clutch cover and recoil housing. The recoil has a couple broken spokes on it and the clutch cover has a whole in it from a loose chain. I've got a C5 I could rob the parts from, but I think it might be the better candidate for the resto.
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Post by edju1958 on Feb 18, 2019 11:17:26 GMT -5
At least you got the piston freed up on this one. Ed
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Post by 5terrysupersaws on Feb 18, 2019 15:46:02 GMT -5
Stuck the drill on it and spun it over fast, no spark. I'm trying to decide if I'm going to take this one apart and restore it. It needs a new clutch cover and recoil housing. The recoil has a couple broken spokes on it and the clutch cover has a whole in it from a loose chain. I've got a C5 I could rob the parts from, but I think it might be the better candidate for the resto. You can quick test the ignition using a 1.5 volt battery to determine if the points are the cause of the no spark. No disassembly is required other than accessing the kill wire at the switch.
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Post by rarefish383 on Feb 18, 2019 16:17:06 GMT -5
Do you just put the battery between the wire and the switch terminal and if all is good you get a spark? The plug looks like it might be original to the saw. I think it's a 6J6. Half of the electrode is gone.
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Post by sweepleader on Feb 18, 2019 17:27:31 GMT -5
Gotta have a good plug, that could be all of the problem if the electrode is that bad. The battery goes between the wire and ground on the saw.
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Post by 5terrysupersaws on Feb 18, 2019 17:29:04 GMT -5
Do you just put the battery between the wire and the switch terminal and if all is good you get a spark? The plug looks like it might be original to the saw. I think it's a 6J6. Half of the electrode is gone. You will need a known good spark plug for the test, at least re-gap the the original to .025" An alternate to the Champion-J6J is the NGK-B6S. See Magneto testing with a flashlight battery for the procedure.
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Post by rarefish383 on Mar 2, 2019 15:18:48 GMT -5
Stuck the compression gauge on it ad it only blew about 30-40 PSI. The piston and cylinder look good. Looks like the ring is stuck in the groove. While I was at it I stuck the gauge on the C51, which I thought was the better of the 2 saws. It only blew about 90 PSI. I looked in the exhaust and at first glance it looked like a solid piece of chrome. Then I looked closer and there is a perfectly symetric grove from top to bottom on the cylinder wall. It's so straight and even it looks like it was machined in there. Oh well. All the metal on this one is very good, so I may use it for a parts saw. My favorite saw auction is coming up in a couple weeks. Maybe I'll get lucky. Last year I got the great running 1050 with new chain for $150. I'd do that again.
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Post by rarefish383 on Mar 4, 2019 14:47:17 GMT -5
HAL-LAY-LOO-YA, I'm doing some old fashioned stump jumpin dancin in circles. When I tested the comp on the C72 the other day I just had a breaker bar on the crank spinning it over and it only blew 30-40 PSI. When I put the flywheel on I had let the dogs flip over backwards, so the recoil wouldn't work. I just went down and pulled the flywheel off and flipped the dogs around and put the recoil back on. I had a hard time spinning it around on the bench. So I put it on the floor where I could put my foot in the handle. Five to six pulls and she was sitting right on 145, I think that will run. Won't get much time to work on it for a while. Going to SC to meet my daughters fiance's parents. Worst part, I'm going to miss my big spring auction where I get all of my big saws, RATZ.
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