Has anyone else noticed this? I have the lS screw 1/16 out from full rich and it still bogs a bit when you wack the throttle. When the bar is in a cut it feels too lean also. I have modified the muffler by milling the muffler opening to 7/16" by 1 3/8". I am wondering if it needs new carb jets.
ms 260 pro/extremely lean?
- Thread starter bwalker
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HUSKYMAN
Addicted to ArboristSite
Opening the muffler will lean the saw out more. Do you have the limiter caps removed?
The bog would be caused by the low speed adjustment and the lack of power in the cut by the high speed
The bog would be caused by the low speed adjustment and the lack of power in the cut by the high speed
The dang carb only has a LS adjustment. It was bogging when simply blipping the throttle with no load. Thats how lean it was. I just got back from fooling with it some more. I turned the LS screw out till it cut the fastest. It also cured the bog. Its kind of a bandaid fix to have to richen the HS by maxing out the LS. Its cutting great now. It seems a bit faster than my 036. Muffler mods really help this saw.
HUSKYMAN
Addicted to ArboristSite
Get a carb off a saw thats 3-4 yrs old and you be able to tune it real well
I thought about that. How much does the older carb cost and will it bolt right up?
treeclimber165
Member A.K.A Skwerl
I've had this same problem with my 026Pro I bought almost new this spring. I may be looking for an older style carb with adjustable high jet also. I'm almost ready to sell the d@mn thing and buy a new 026 without the 'improved' carb. 
fix it
OK quit bellyaching about the fixed jet. Fix it. I have good luck with them. The inlet lever must be set correctly. I am finding many of them too low. That cures about half of them. The other problem is too small a jet. Stihl has them in different sizes, usually one larger will cure it.(unless you know how to drill them)
I replace very few carbs (usually due to bad fuel or water). Aways check the inlet lever first.
OK quit bellyaching about the fixed jet. Fix it. I have good luck with them. The inlet lever must be set correctly. I am finding many of them too low. That cures about half of them. The other problem is too small a jet. Stihl has them in different sizes, usually one larger will cure it.(unless you know how to drill them)
I replace very few carbs (usually due to bad fuel or water). Aways check the inlet lever first.
treeclimber165
Member A.K.A Skwerl
I haven't had much luck with the fixed jet setup. I already replaced it once, and opened up the inlet lever a little. I ordered the jet, picked it up a week later, tore down the carb, replaced the jet (and finding that the purchased jet recommended for my area was identical to the one I took out), put the carb back together, started the saw, and at that point found out that I still hadn't fixed it. Now I have to order ANOTHER (prepaid, non-refundable) jet, wait a week, pick up the jet, tear the carb down AGAIN, change the jet, put it back together, and HOPE it is the right jet!
Yeah, non-adjustable carbs are not that much of a PAIN-IN-THE-A$$ to adjust! Just as simple as turning a screw on the old style!
Yeah, non-adjustable carbs are not that much of a PAIN-IN-THE-A$$ to adjust! Just as simple as turning a screw on the old style!
tundraotto
Addicted to ArboristSite
Ben, what are your max rpms. Its a high speed saw so I am sure its pretty darn lean at the stock figures.
tones of timber
New Member
My reply by know means has any validity, but my underedstand of a small displacment high output engine may not be correct. A by product of small displacment high output, high rpm engine is that u sacrafice low end throtle respone and power to achieve great power at the latter part of of the rpm range. Low rpm torque should be able to overcome its rotating mass quite easyly with no load , as u increase load at low rpm engine has harder time overcoming load. In my OPINION the problem may not be a carburator but more with the intake port design style, and piston port design if equipted. I am sure my opinion will get torn up like a fresh cut log with a new chain. So maybe we can all agree to disagree about somethings
treeclimber165
Member A.K.A Skwerl
Ben,
I have the parts breakdown for the MS260 and MS260Pro. The carb we have is a WT-403A, part # 1121 120 0610. The carb for the MS-260 with adjustable jets is a WT-426, part # 1121 120 0650.
Email me if you want a copy of the parts breakdown in PDF.
I have the parts breakdown for the MS260 and MS260Pro. The carb we have is a WT-403A, part # 1121 120 0610. The carb for the MS-260 with adjustable jets is a WT-426, part # 1121 120 0650.
Email me if you want a copy of the parts breakdown in PDF.
Guys I have got it bandaid fixed for now by maxing out the low speed jet. I plan on getting the next size jet and trying that.
Stihl tech, I have to disagree with you on the fixed jet carb. IMO it has no use other than to shorten a saws life and satisfy some fatass at the epa. Out of the box the saw stunk. It was so lean it had about half the power it should in the cut and the unloaded rpm was 14,800.00. After I richened it up to get peak cutting speed it is showing 13000. I quit impressed with this little saw now that I have the high end rich enough.
Tons of timber, The power charachteristics of this saw are more high rpm biased than say a 044 or a 372, but in this case the saw is great once it is tuned correctly.
Treeclimber, Do you know the differances between a pre epa 026 and a 260 pro? I assume its the carb and muffler. I hope you can swap parts from one to the other, but they may not interchange.
Stihl tech, I have to disagree with you on the fixed jet carb. IMO it has no use other than to shorten a saws life and satisfy some fatass at the epa. Out of the box the saw stunk. It was so lean it had about half the power it should in the cut and the unloaded rpm was 14,800.00. After I richened it up to get peak cutting speed it is showing 13000. I quit impressed with this little saw now that I have the high end rich enough.
Tons of timber, The power charachteristics of this saw are more high rpm biased than say a 044 or a 372, but in this case the saw is great once it is tuned correctly.
Treeclimber, Do you know the differances between a pre epa 026 and a 260 pro? I assume its the carb and muffler. I hope you can swap parts from one to the other, but they may not interchange.
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GeorgeWLogger
ArboristSite Operative
Treeclimber- can you email me the pdf of the parts breakdown?
Stihltech- Do you have the jet part numbers for the 026PRO can you list them? I have two 026'ss one older well used and one about a year old. The older 026 will cut circles around the new one with the non-adjustable carb saw. Should I blame my dealer for not being skilled enough when setting up my saw?
Stihltech- Do you have the jet part numbers for the 026PRO can you list them? I have two 026'ss one older well used and one about a year old. The older 026 will cut circles around the new one with the non-adjustable carb saw. Should I blame my dealer for not being skilled enough when setting up my saw?
treeclimber165
Member A.K.A Skwerl
GeorgeWLogger
I'd be happy to, but you will need to email me so I have an email address that I can reply to.
The only two jets listed in my PDF parts list are the stock jet and a high altitude jet (even leaner than stock)
Stock jet- 1120 121 5600
hi alt. jet(0.52)- 1121 121 5602
I'd be happy to, but you will need to email me so I have an email address that I can reply to.
The only two jets listed in my PDF parts list are the stock jet and a high altitude jet (even leaner than stock)
Stock jet- 1120 121 5600
hi alt. jet(0.52)- 1121 121 5602
bersh
New Member
Re: fix it
Stihltech,
How is the inlet lever set? I can't find any mention of it in my workshop manual.
Thanks,
Scott
Stihltech,
How is the inlet lever set? I can't find any mention of it in my workshop manual.
Thanks,
Scott
Treeclimber, If thats the case I will be drilling out he stock jet. The place i work has a fulltime machnist so it shouldnt be aproblem. BTW forward me that pdf
George, E mail me. I have been tryting to get ahold of you forever.
George, E mail me. I have been tryting to get ahold of you forever.
dozerdan
Addicted to ArboristSite
I really dont like the non adjustable carbs on the 026 pro but they are here and we have to deal with them.I have Power Ported over 1/2 dozen of the 026 pros and all but 2 worked fine with the 52 jet.On one of them I used the old style carb and it worked out just fine,on the other one I used Stihl part number
1130 121 5600 ,that is a 54 jet,also worked out very well but you still have a non adjustable carb.
Later
Dan
1130 121 5600 ,that is a 54 jet,also worked out very well but you still have a non adjustable carb.
Later
Dan
treeclimber165
Member A.K.A Skwerl
Ben and George,
If you want the PDF, I need an Email address! I cannot attach files if I E-mail you through ArboristSite, and it will not reveal your address. Click the email link below any one of my posts and EMAIL ME so I can return the email with the PDF file attached.
Dan- Thanks for that part number. I will try a larger jet for $5 before buying a new carb.
I just ordered it, $3.95 plus tax. It will be in next week. I'm trusting the part number you supplied because the dealer only had it listed as a jet. He didn't have any info on what size it was or what application.
If you want the PDF, I need an Email address! I cannot attach files if I E-mail you through ArboristSite, and it will not reveal your address. Click the email link below any one of my posts and EMAIL ME so I can return the email with the PDF file attached.
Dan- Thanks for that part number. I will try a larger jet for $5 before buying a new carb.
I just ordered it, $3.95 plus tax. It will be in next week. I'm trusting the part number you supplied because the dealer only had it listed as a jet. He didn't have any info on what size it was or what application.
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lever height
On the WT carb, the lever must be flush with the two small bosses either side of it.
The 52 jet is usually stock, the 53 or 54 usually cure it.
I just don't like that too many adjustable carbs get adjusted to try and cover up other problems.
On the WT carb, the lever must be flush with the two small bosses either side of it.
The 52 jet is usually stock, the 53 or 54 usually cure it.
I just don't like that too many adjustable carbs get adjusted to try and cover up other problems.
Dozer, when you say work fine do you mean that by richening the LS way out you where able to get it to run acceptable on top?
In my book this this isnt really acceptable as the low end blubbers and burns dirty as evident by the black deposits on the bar and case. I think I am going to try the next larger jet and then adjust the LS back into its normal range which in effect should make it run correctly throughout the power band.
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