Mark_Skyland

The serial numbers are etched into the engine housing next to the starter cover. They usually begin with a C then have 10 digits. All of our latest ones have started with C879.......

As mentioned above it looks genuine to me. I haven't seen any fake 2511's yet.

Spud knows his stuff on these machines. 200t parts are now getting scarce, no more stock of the major metal parts, crank, cases, cylinders, pistons etc. Some plastic parts are still available but they wont be around for long! I suggest to always go oem on a machine that's used for pro work. Non oem is very hit and miss, even a non critical part might just not fit and you can spend more time than its worth trying to make it fit

Two strokes need to be run. As above, use the machine as its supposed to be used. Don't let it sit at idle and don't stand there revving the tits of it. If had plenty of new chainsaws over the years and ive always just put them to work straight away. If the machine is running flat out for a decent amount of time then I suggest letting it cool down a bit every now and then.

As above, dont spend anymore time or money on those machines. Its worth going back to the auction site if they were selling those machines as Stihl MS440's

I cant remember ever having seen the same issue with the husky caps tbh.

The video to you tube doesn't seem to be showing for some reason. Try searching this Stihl MS 170 Oil system repair. Changing Oil pump, worm gear, oil line, service.

I didn't the first time and had to strip another saw down to check as I didn't have the stihl tool! This video suggests that you just push the pump all the way down, it might be correct but I couldn't say for sure.

I measure the depth the depth of the pump before I remove it, I think its around 5mm.

I haven't has a chance to rebuild the round tube pole saw but I've done two square tube ones this week, a lot easier by far!

Ill find a workshop manual and send it to you. Those pumps need to be inserted quite specifically or they wont work. The pump needs to be set to the right depth and it needs to be facing a certain way. If I get a saw in with those pumps and the pipe or filter isn't blocked I just replace the pump, its not worth cleaning it and putting it back in as it never works.

You're a better man than me. I've always struggled to rebuild these things. I did one a month or so ago and I've got another one to try and sort out this week. Half of the problem is that the bearings break down so a lot of the parts have moved and arent in the right place. There is a good video on you tube somewhere, ill try and dig it our for the OP. You need to make sure that you have the right bearings as there are two types, they are installed the correct way, the springs are installed correctly and that you have the splined shaft installed correctly as it has a circlip that makes sure it moves when you extend the pole. IIRC! I think one of the issues is that the stihl diagrams are misleading and they don't show how its properly put together. Ill try to take some photos when I put the next one back together.

TBH I havent worked on any machines that have had a big end failure. Do you mean the main bearings?

If you cant get your hands on a 2nd hand saw before buying it then its a bit of a lottery IMO. On a big saw like the 661 you can get away with a few issues, even a knackered engine if its cheap enough. I wouldn't pay more than 500 maybe 600 for a second hand one unless you know the operator or can try it before you buy. Don't forget, on big saws bars and chains aren't cheap, you need to factor that in when comparing 2nd prices to new.

It might not be causing the issue. As I said the vid looks like its oiling as it should. If the chain isn't constantly getting slack and the chain doesn't look dry then its probably ok. I would still expect some splatter of oil off the end of the bar though.