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Showing results for tags 'piston cylinder problems'.
Found 2 results
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Hi all - bit of advice please - this head came off a ms660 that had just been out the shop after blowing up once , only to die again instantly from crank bearing disintegration so head was brand new , I’ve cleaned the smudges out to find a single score running from top to transfer port , scratch can be felt with finger but it’s shallow and not down to the metal , seems the piston took most of the shrapnel to the top and bashed some into the top dome of the head (note the pock mark above score) will it be alright to reuse or is it junk ?
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I have been trying to diagnose a fault on a Husqvarna 435. The saw was initially running poorly and hot. It was taken for a serviced by a local company after which the saw wouldn't start. It was taken back. The company swapped the carb which didn't fix it then they said it might need a new piston and quoted a high price.. The owner brought the saw to me. The saw will fire but won't run for more than 1/2 second, even with direct priming with carb cleaner. The plug has been changed and it produces a healthy spark which jumps a gap. Compression was measured at 120 psi. The piston ring is free and piston skirt un-scored. There are some mystery scratch marks on the back of the cylinder opposite the exhaust post and on the front of the piston below the ring but they seem quite superficial and not enough to cause a problem. On removing cylinder, there were no foreign objects, nothing stuck in the transfer port, manifold and cylinder seemed in reasonable condition. There were dark marks on the piston skirts so I think there is some blow by past the ring. Just in case, I stripped the carb to look for obvious faults but all looked clean and in good condition. I have also tried every tuning point of H and L including the standard tune in am effort to get this saw to run at any RPM. Has anyone any suggestion where I should go from here? My feeling is that it needs a new piston or piston and cylinder but I am not at all sure. Thanks for any help
