Pete H

I take it 260 are not favoured? It cuts wood, eventually, so that’s good enough for me

Good evening all, Sorry for late update on my MS260. It’s fixed, starts third or fourth pull and runs in my opinion well. The problem was the nuts I had used to hold carb to the cylinder. I bought the saw off an auction site. All was well for a while and then it started to bog down so I decided to remove carb, clean it and fit new diaphragms etc. However, when I removed the air filter housing there were no nuts holding carb to cylinder. No idea why, but after asking on here some time ago was this correct and being told no I set about correcting this, I could see that the nuts needed to be a bit slimmer than standard so I filed them down. Problem sorted so I thought. Anyway, it became a swine to start, I was directed to a professional saw dealer and he suggested that as I was only using it now and again to use easy start to get it going. Which I did, until the easy start ran out, there wasn’t a lot in the tin anyway. The saw started to bog down and scream, I was cheesed off with it and just shoved it under the bench with the intention of buying a new one. Now this is where the wife came in, as I was always successful in repairing friend’s equipment she made it clear that as I had the ability to repair my own so why was I thinking of buying another one. Good point I thought, and who was I to argue. So, I retrieved the saw and stripped it, cleaned it reassemble and try to start, only by putting a drop of fuel on the filter housing would it start, but very soon scream. Take it apart, again, that’s when I came on here to ask for help, which I was grateful for. Just by chance, I started to think in an old fashioned way, choke and what a choke is for??? That is when I picked up one of the nuts and put in the recess of the filter housing, it was proud by about a 1/16 (2mm). Light bulb moment, I can hear you all saying stupid bugger, it was then that I realised that the thickness of the nut/s we’re holding the air filter housing off the carb body, bearing in mind that the choke butterfly is part of the housing. Obviously on cold start it was drawing air and cancelling out the effect of the choke. I reduced the thickness of the nuts and “bingo” So, apart from the above, the rest is history so to speak. I did also replace both diaphragms, pump and metering. Sorry for the lengthy post, but it may but I doubt it help someone else. Thank you all again. Pete

Hello Muddy, On my MS260 the choke flap is part of the air filter box, a plastic two piece unit with a nylon type mesh welded to the plastic frame. So, the filter needs to be fitted to have choke. thanks again, Pete

Thank you Chris, and all. I’m clutching at straws to be honest. So, I’m going back to it soon, I’ll let you all know. Another thing I noticed was that the “mesh” was overlapping the filter housing face in one area. I’ve scraped that off, so?.. Pete

Your a star Muddy, I’ve got compressor in workshop with regulator. If I turn pressure right down that should work hopefully or I’ll rig up a wheelbarrow tyre and use that. cheers. The odd thing about this saw was that when we acquired it, the two nuts holding the carb in place were missing. The only thing holding the carb in place were the air filter screws. I cut down two nyloc nuts, but, when scratching my head and thinking of old engines needing choke I thought as mentioned by you all, air leak. When I checked my nuts, excuse the pun, they were a little above the face of the air filter box, perhaps not sealing the filter face to the carb body???? What do you professionals think? Pete

Hello Muddy, Do you mean dunk it in a bucket of water while pumping it up, excuse the daft assumption.

Thanks again all.

Thank you Stubby, Peatff, appreciate the reply, I’ve always repaired mowers strimmers saws, for myself and friends etc. I’ve started to watch carb vids to learn more. This has confused the life out of me, that’s my I’ve turned to you professionals. I’m a mechanic by trade, and remember certain cars had certain stupid faults that you would never believe if it hadn’t happened. I was hoping something like this would be the case…🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻 Anyway, I’ll follow all the advice I’ve been given, thank you all. Pete

Thank you all for your help, sorry for late reply, working. I’ll do what suggested but, in all honesty I’ve already been down that route. There is plenty of fuel to carb and air filter is the washable type which I’ve done. I’m feeling guilty that I may appear to be ignoring you, I’m not at all. Stephen asked about usage, it came to me second hand, so until me I have no idea but it was mildly difficult to start, 10-12 pulls but once warm fine. My latest attempt needed me to drip fuel onto the air filter and once going after a minute or two it seemed to scream ( weak mixture???) followed by “bogging down” eventually stopping and refusing to restart. As much as I threatened it with the skip, it would not start until more fuel drips.

Good evening all, I wonder if someone could help please? I have a MS260 which for some time now has been almost impossible to start. I’ve cleaned the carb that many times I just mention it and it detaches itself. I’ve checked fuel and impulse lines which to the naked eye look good as with ignition/spark. I’ve heard that crank seals can be a problem, but, would this give the above problems? I do not have the equipment to do vacuum pressure checks. Or should I just replace the carb??? (And hope) thanks all, Pete

Ok, another senior moment. Apologies “spud” for some barmpot reason I thought the name was raffle, I can see now that it reads “Raffle sponsor”. Anyway, back to the drawing board. pete

Hello all, Me again, thanks once again. What i forgot to mention was that as the saw became harder and harder to start I spoke to a tree surgeon friend of mine who put me in touch with a Stihl agent, he suggested, as I did not use the saw for some time, squirt a bit of Easystart to “get it going” This did actually work, however, as mentioned it became unpredictable and erratic and bog down. I then decided to once again remove/strip carb and this time replace the diaphragm with an aftermarket kit. All looked identical so I felt happy, but unfortunately the problem was still there, not immediately, but soon after a short period of running. This is where started to look towards a new carb but became unsure what to order as Stihl UK told me that this was not the recognised carb for the year and model/serial number. Now silage is over I can return to the workshop and will obviously persevere with all your suggestions. I can only thank you all once again, I’m determined to find the cause/fault. Cheers, Pete

My apologiesRaffle for the delay in replying/acknowledging your reply. Trying to get the silage in. What can I say, such an in-depth response to my problem. With great respect to all here it’s good to have the benefit of experience such as yours Raffle. I’ll let you know how I get on as I have only browsed your reply. thanks Pete

Thank you all for your help, I really do appreciate it. I can normally sort this type of stuff out but for fear of labouring a point my confusion is that Sthill uk say that the carb WT394 was not fitted to this saw. Anyway, I’ll take all your advice and pull it out of the bin and try again. pete

Good evening all, I’m Pete from Bersham near Wrexham North Wales. I’m a newbie here so be gentle, I’ve been a chainsaw user for many years mostly for home/farm use for trimming back and firewood. I have always maintained/repaired my own equipment, replacement of chains bars and dismantling of carb for running issues etc. However, I have a problem with a MS 260 which my son bought second hand, it’s an old saw and up until now has never really been a problem. I was experiencing starting problems leading up to this. My reason for asking you professionals is that after cleaning the carb many times it starts, bogs down and in my opinion screams at high revs (weak mixture). After “rooting” around I believe that the carb fitted is incorrect, WT394. Contacted Sthill and they have no record of my saw? I know that the simple answer would be replace the carb but this is a puzzle I would like to get to the bottom of. I was a mechanic by trade and my preference is to repair rather than replace, that to me is the easy option. My apologies for an initial lengthy post, but I would be extremely grateful for some input/advice on this. Thank you all, Pete