Seamus

Thanks Spud I got some 280 grit w/d and have been rubbing the bore and it has made some improvement - see photos. But above the exhaust port the grooves are deeper especially on both edges of the exhaust port. After a lot of rubbing there was no improvement in these grooves and I don't see them coming out. Don't know how well the photos will show this.

Thanks Spud I checked the specs and all the 50 series have the same stroke. I have spent the last couple of days on and off applying the acid to the pot. There is a slight improvement but there are grooves in the liner which will not lead to a satisfactory performance in the end. I could probably improve it a bit more but it is going to be around the £30 mark to take a chance, and maybe that is better spent on a new pot and piston? Whatever I do depends on the MOT on my truck tomorrow which is bound to be more than I expect. I am enclosing photos of the original and the latest.

Ok - thanks Note taken on the seal. I will try the cleaning tomorrow. If I do have to go down the new pot route it seems that the 51 is available. Are they interchangeable with the 50. The difference I can see is the addition of a decompression valve and maybe the piston is a mm or so larger.

Thanks - I have a bit of that lying around - guess it needs to be diluted a bit.

Thanks Spud I have been reading up on Nikasil coating which I assume they used on this saw. The plating they say is so thin that any scratched will go through it. To me they seem to be too deep and it is unfair on you to ask to judge without seeing it first hand. If it doesn't work out then I have to start over again. The carb to pot connection appears to be still a good fit. I don't think the clutch seal would be the issue since the smoke was only coming out from the flywheel side. I have taken the flywheel off and the seal looks good inasmuch there is no sign of any oil, nor on the back of the flywheel - I know not foolproof. If I do change that seal, can it be prised out rather than splitting the case? There is one possibility of the pot to crankcase gasket. See green arrow on photo, where is might be leaking. More photos enclosed. The last one in case it interests anyone, is my take on locking the piston to remove the flywheel or clutch.

Thanks - I will look those up. I have now stripped it down so see what you think about it please. I cannot feel any vertical play in the piston, con rod, big end. There is very slight lateral play, not the slide side to side, just very slight if you sort of try to bend the rod. There is no play in the crankshaft bearings. The piston ring is seized on the exhaust side, though I expect that would be expected. Would this account for the blow by creating the smoke via the flywheel? Here are the pics. Exhaust is at the bottom in case anyone is not familiar with it.

Thanks for all the replies. It has always been run with 50:1. Spud Thanks for the feedback. I can just get my the tip of my little finger nail in there and can feel the ridges on the piston. So the pot has to come off and am sure the cylinder will be scored so let's right that bit off. What do I need to look for in the crankcase that might be causing problems? Bearing in mind that I am now retired and the saw will only be used domestically, I have seen that there are some 3rd party piston and pot assemblies available for the 50. Are these up to scratch (unfortunate phrase) for the use I am going to put the saw to? Thanks David

I managed to get the muffler off after soaking it with WD overnight and have attached some pictures of the piston though the port. There does seem to be some scoring but don't know how bad you judge that to be. It does not look to be acceptable to me. I am very unfamiliar with 2 strokes. All my experience has been with car engines. When I turn it over with the starter, plug etc removed it seems to latch at TDC. Though just thinking about it maybe that is when the coil lines up with the coil? Would appreciate your thoughts on this.

Thanks will do that. Came across a U-Tube video on that last night.

I have a Husky 50 which I have had from new. Cut a few trees but mainly used on through & through timber from the mill, so quite light use. It has always been a good starter until this year. I drained the fuel out (I have read here that that should be done). When refilled (normal lead free) it then ran ok, but not an easy start. I had to cut up an old fallen oak from the storms and it was having to work quite (had a new chain on it). Then noticed that smoke was coming out of the vents around the starter housing. Left it to cool down and after would not start again unless one of us held the throttle full open. It worked but would not idle. Next day it would not start under any condition. Put in a new spark plug as I could not see a spark when I spun it over. Then suspected the ignition module so have replaced that. Got a spark but no start. Putting my thumb over the plug hole I can feel compression. So now I am wondering where I should go next. I would appreciate any advice anyone might have. Thanks