Hello There!!
I've joined up to post this question, so I'd like to first thank you all for the info I've gained over the years as a visitor. I own two saws used for firewood only, and the advice from these forums is invaluable. I probably would've burnt the things out by now if it hadn't been for the generous member contributions in places like this, so once again I thank you all.
I've been given a well used 60cc Sthil by a friend, who in turn was given it as a problematic saw. He assumed it to be an MS361 (the badge was missing). He cleaned it up, and gave it to me as a Xmas gift. It seems to be a worthwhile project. It was was, however, difficult to start and seemed to overheat fairly quickly, and it didn't seem to want to tune up decently (I can't say for sure that it was actually overheating, but it didn't feel "right"). So I've erred on the side of caution and put it to the side, and decided to invest some cash and time to see if I can get it decently refurbished.
The clutch springs and shoes were in a bad way, so I sourced a very good condition used OEM replacement assembly. I'm not sure if my logic is correct, but I figured that the clutch engaging at low speed would cause jamming when pulling over, and possibly cause tuning problems.
But my main cause for concern and confusion is the top end. It's obvious that it has been tampered with - the heat shield was missing, the cylinder's exhaust / muffler flange was pitted and had a stripped thread, and I could see black marks on the piston. So I've stripped it down, and matched-up a used OEM piston and cylinder pair on E-Bay, which came back in fantastic condition. The replacement was was listed as an MS341 part, and when I bought it I honestly thought that the MS361 / MS341 cylinder would be interchangeable (as are most of the parts). But it turns out that the MS361 should be closed ported, and the MS341 open ported. The cylinder that I removed is open ported, the cylinder that I bought as a replacement is also open ported, so all things being equal I am swapping like-for-like.
BUT - I'm wondering what might happen if the saw is indeed originally an MS361? Would the carb and ignition be set up differently, and if so am I risking wasting my time fitting the open ported cylinder? Would I be risking damage? Other than the cylinder is there any way of establishing whether the saw is an MS361 or an MS341, and does it matter which cylinder I fit? In other words - if this is actualy an MS361 which has had the wrong cylinder fitted at some point, am I in danger of replicating the original starting and running problems by changing like-for-like?
Also, the original cylinder has a 2 - 3 mm diameter hole drilled through the inlet flange (see pic, right-hand side), from outside to inside. The replacement I bought doesn't have this hole. I'm guessing that this may have been a later design upgrade, so again I'd appreciate it if anyone might be able to enlighten me on this, and what might be the ramifications of fitting a cylinder without the hole, or is it worth me drilling it myself?
Many many thanks in advance to anyone who may be able to offer advice. I know very little about combustion, but I'm no dummy and can readily apply myself.
I've joined up to post this question, so I'd like to first thank you all for the info I've gained over the years as a visitor. I own two saws used for firewood only, and the advice from these forums is invaluable. I probably would've burnt the things out by now if it hadn't been for the generous member contributions in places like this, so once again I thank you all.
I've been given a well used 60cc Sthil by a friend, who in turn was given it as a problematic saw. He assumed it to be an MS361 (the badge was missing). He cleaned it up, and gave it to me as a Xmas gift. It seems to be a worthwhile project. It was was, however, difficult to start and seemed to overheat fairly quickly, and it didn't seem to want to tune up decently (I can't say for sure that it was actually overheating, but it didn't feel "right"). So I've erred on the side of caution and put it to the side, and decided to invest some cash and time to see if I can get it decently refurbished.
The clutch springs and shoes were in a bad way, so I sourced a very good condition used OEM replacement assembly. I'm not sure if my logic is correct, but I figured that the clutch engaging at low speed would cause jamming when pulling over, and possibly cause tuning problems.
But my main cause for concern and confusion is the top end. It's obvious that it has been tampered with - the heat shield was missing, the cylinder's exhaust / muffler flange was pitted and had a stripped thread, and I could see black marks on the piston. So I've stripped it down, and matched-up a used OEM piston and cylinder pair on E-Bay, which came back in fantastic condition. The replacement was was listed as an MS341 part, and when I bought it I honestly thought that the MS361 / MS341 cylinder would be interchangeable (as are most of the parts). But it turns out that the MS361 should be closed ported, and the MS341 open ported. The cylinder that I removed is open ported, the cylinder that I bought as a replacement is also open ported, so all things being equal I am swapping like-for-like.
BUT - I'm wondering what might happen if the saw is indeed originally an MS361? Would the carb and ignition be set up differently, and if so am I risking wasting my time fitting the open ported cylinder? Would I be risking damage? Other than the cylinder is there any way of establishing whether the saw is an MS361 or an MS341, and does it matter which cylinder I fit? In other words - if this is actualy an MS361 which has had the wrong cylinder fitted at some point, am I in danger of replicating the original starting and running problems by changing like-for-like?
Also, the original cylinder has a 2 - 3 mm diameter hole drilled through the inlet flange (see pic, right-hand side), from outside to inside. The replacement I bought doesn't have this hole. I'm guessing that this may have been a later design upgrade, so again I'd appreciate it if anyone might be able to enlighten me on this, and what might be the ramifications of fitting a cylinder without the hole, or is it worth me drilling it myself?
Many many thanks in advance to anyone who may be able to offer advice. I know very little about combustion, but I'm no dummy and can readily apply myself.
