MS461 hard to pull rope
- Thread starter mountainguyed67
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It has about .00045” runout.
I was a machinist eighteen years, still have my stuff.
Smooth rotation all the way around too.
I was a machinist eighteen years, still have my stuff.
Smooth rotation all the way around too.
Side view.
The lines on that piston are from debris getting past the air filter..I see no reason to replace that piston unless it's out of clearance. Polish it up a little and run it. Same with the cylinder. I would do it by hand with either a green pad or 220-400 wet/dry sandpaper.
Same with the rings?
I forgot to tell you guys the piston grooves are squeezing in on the rings. That’s the reason the shop guy said to replace the piston.
60% of the cost, 60% of the power, 400% of the headaches.
Better off buying used oem or cleaning up the one you have
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Deleted member 135597
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Stick with your original plan, clean up cylinder and get a new piston kit. Reassemble, do press/vac test and get back to falling those trees. There’s no need for a new cylinder.
What do you think about the muriatic acid test? Necessary?
What exactly is the test looking for? Aluminum transfer? Cracks?
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Deleted member 135597
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It’s not really a test, it’s a method to remove the transfer. The acid eats the aluminum, but won’t hurt the plating on the cylinder. I’ve done it and it works, down fall is if the cylinder has a pit in the plating or a score, the acid will get to the aluminum underneath the plating and eat it. If you clean it up with scotchbrite and wd40, you will be able to see if there’s any transfer on the plating, then you can decide what method you want to use to remove it. I don’t think you have any transfer on that cylinder that a little elbow grease with scotchbrite won’t remove
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Deleted member 135597
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I just cleaned up a straight gassed 660 cylinder with no acid, just sandpaper and scotchbrite, came out beautiful. Compression is 160. Acid is quicker, but you risk damaging the cylinder if your not sure what’s transfer and what’s a defect in the plating.
Okay, thanks for the clarification.
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Deleted member 135597
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The only area you might have some transfer is where this was riding in the cylinder, it’s hard to tell from the pics.
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Deleted member 135597
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Skip to the final scotchbrite part, this is all you should need to do, the cylinder will look brand new if you make a mandrel like this for a scotchbrite pad, or you could do it by hand.
Straight nonsense! If the rings are tight it's just hardened deposits in the groves that can be easily cleaned out. Now that we know the filter was letting debris into the engine, what likely happened was the heat of the engine turned the sap in any wood particles into a depressingly effective glue that stuck the piston to the cylinder when the engine was shut off and cooled down. That's probably why it was hard to turn over after sitting for awhile. The piston looks like it should be recoverable, minor scratches low down on the intake side aren't too critical whereas deep scratches at the top of the piston are.
New piston.
So I’m talking to a knucklehead? I’m not one to assume someone knows what they’re talking about for any reason, I check different sources.
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Deleted member 135597
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Well from what you said, he told you that this was a lean seizure that caused this piston damage, I would say you could find more accurate sources for your information. Your mechanically inclined, with that, a service manual, these forums, and a camera, you have everything you need to diagnose and fix any saw related issues you may run into.
Need some further explanation here. The ring groves in a piston do not change dimensions, but if there is a deep scratch through the ring area, the scratch may have deformed the piston into pinching the rings and this maybe what your mechanic was talking about even though from the pics, it doesn't seem to be the case. Any minor grove damage like this can easily be dressed out with the appropriate needle file so the issue becomes, are the scratches deep enough to effect compression? If the piston cleans up with minor scratches and the rings show no damage with the right end gap, the engine would probably run just fine, but on the other hand, if it is all apart and you don't mind spending the money, it would make more sense to just put in new piston and be done with it.
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