Stihl MS260 WT-426S Carb Questions

[Allan.K]

I just got mint shape carb from Lakeside53 today a WT-426S..I checked the jet and it has a .48 size jet in it did some checking and found out it is a high altitude jet....Next I am at 1400ft sea level what would be the jet to put in it...Plus I am doing a Muffler Mod too...Next how in the heck do you get it out..There is no slot too put a screw driver in to take it out...Plus I would like to have the part numbers to the jets.. I have downloaded two PL's from a site that was on here .. And they show no part numbers for the jets..

Thanks for you time...
Allan.K

 

[Lakeside53]

The.48 jet is the standard jet -the .46mm is the high altitude jet. Not sure what IPL's you are looking at, but mine have part numbers - 1121-120-5400 for the .48, and 1121-120-5601 for the .46.

That carb was saw tested and was right on the money at 400 feet.

If you did want to take it out, it presses out from the metering chamber through to the venturi.

At your altitude, just the standard jet with a standard muffler.... If you mod the muffler you will definitely need to enrichen it anyhow.

Do one thing at a time. Install the carb with the factory muffler. The carb settings should be close to 1 turn out for both high and low. Then do the muffler mod, carefully... if you are drilling two holes, one above and one below the original hole, then start at say 3/16 each and work up. You don't want to get too big... For each "test" size, retune the carb to MAX of 14,000. I did an 026 yesterday (took out the WT403 and put in a WT22C) that popped from 13k to nearly 15k without carb re-adjust... and that was with 1/4 inch holes above and below the original hole.

The 426 H screw only adjusts about 15% of the overall gas flow, but unless you have some crazy muffler mod (you don't need much..), it will work great.

 

[skwerl]

In my experience, by the time I tore down the carb and replaced jets 3 different times and ended up running the saw for several weeks with it too lean (jets always had to be ordered with a week wait between order and being able to pick them up), I ended up with a half-fried saw and many dollars sunk into a garbage carb that still wasn't right. I finally got smart and bought a used adjustable carb but by that time the saw had pissed me off to the point I replaced it with a Husky 346XP. A month later I gave away the 026 and to this day won't own another.

Save your frustration and your saw motor, get the adjustable carb now and toss the POS fixed jet. Or sell it to Stihltech since he likes them so much.

 

[Lakeside53]

In my experience, by the time I tore down the carb and replaced jets 3 different times and ended up running the saw for several weeks with it too lean (jets always had to be ordered with a week wait between order and being able to pick them up), I ended up with a half-fried saw and many dollars sunk into a garbage carb that still wasn't right. I finally got smart and bought a used adjustable carb but by that time the saw had pissed me off to the point I replaced it with a Husky 346XP. A month later I gave away the 026 and to this day won't own another.

Save your frustration and your saw motor, get the adjustable carb now and toss the POS fixed jet. Or sell it to Stihltech since he likes them so much.

The WT 426 is an adjustable carb... works just great as is...

 

[West Texas]

Take Lakes advice. Don't screw with the carb, put it in, start it up, and tweak it if you must. I'm at 6000' and I also bought a carb from Lake and it required very little tweaking. After you get the saw running good; then do the muffler mod and then tweak the carb again for another minor adjustment.

Elevation and muffler mods are not totally earth shaking events; although both benefit from some tweaking. But unless you are a pro with carbs, don't mess around with changing jets; if its not broke don't fix it.

And contrary to some, I love the Stihl 026/260 Pro series. Just so happens that my muffler modded 026 is so good (with a Lake adjustable carb in it) that I recently sold my 260 Pro in order to buy another 361, which I needed. Everyone needs at least three saws or more.

 

[skwerl]

Sorry, I was thinking about the POS 403A fixed jet carb. Ignore my previous rant.

 

[Lakeside53]

Sorry, I was thinking about the POS 403A fixed jet carb. Ignore my previous rant.

....and you're absolutely right about those... lucky to pull 12k at seal level, but when you buy those saws used, they've never run lean! The saw I bought yesterday has a muffler and screen full of carbon - homeowner.. completely blocked air cleaner, 403 carb... ran so rich it barely ran. Cleaned it up, replaced the carb and it looks and runs like brand new!

 

[Allan.K]

I really thank you for the carb. lakeside53.. The carb on it now is a 403.. I was just wondering about the different sea levels the jetting...Why I asked that I used to drag race a sled back in the 90's.. And I had to change the jets according to sea level, temps, stingers,fuel and etc...So I was just wondering about sea levels on saws.. Oh for the IPL's I down loaded 2-IPL"s from giftsofwood..a 026 IPL and a MS260 IPL..I am heading out too the shop to install the WT-426 on the MS260 and I am going to tach it ....And no I am not going to mod the muffler right away the only thing I did is take out the screen on the muffler for now...I will be back in a few ...

Allan.K

 

[Allan.K]

Before I changed carbs..I took out the older fuel and ran it out and put in fresh fuel and oil mixed at 32:1 like I always have ... I tached out the 403A is was running alittle under 12k.. I switched carbs now she is hitting around upper 14k to lower 15k.. So I truned out the high side and it dropped down around 14.4k to 14.6k..I tested it with the clean air filter and B&C... Is there away I could drop the rpms alittle more??? I really like this carb alot...Is there maybe a bigger jet for it ?? Or what could I do .....Oh Lakeside53 do you mind if I gave you buzz .. I have some more ?'s on some other things about a stihl I am working on and few other carb ?'s...

Thank you for your time and knowledge
Allan.K

 

[Lakeside53]

Before I changed carbs..I took out the older fuel and ran it out and put in fresh fuel and oil mixed at 32:1 like I always have ... I tached out the 403A is was running alittle under 12k.. I switched carbs now she is hitting around upper 14k to lower 15k.. So I truned out the high side and it dropped down around 14.4k to 14.6k..I tested it with the clean air filter and B&C... Is there away I could drop the rpms alittle more??? I really like this carb alot...Is there maybe a bigger jet for it ?? Or what could I do .....Oh Lakeside53 do you mind if I gave you buzz .. I have some more ?'s on some other things about a stihl I am working on and few other carb ?'s...

Thank you for your time and knowledge
Allan.K

How many turns out are you? on the H screw? the 426 is very fine threaded so it take more than you may think to enrichen it.

Sure, call after 7pm PDT. You should have the number in your old email, if not I can PM you.

 

[Allan.K]

Well I truned it out 2 more turns then what it was..I went more but no change in rpm..Yes I still have your phone number on my pm ... What time is it there .. Here it is 8:30....

Thanks again for your knowledge
Allan.K

 

[Lakeside53]

6.23pm

 

[Lakeside53]

Well I truned it out 2 more turns then what it was..I went more but no change in rpm..Yes I still have your phone number on my pm ... What time is it there .. Here it is 8:30....

Thanks again for your knowledge
Allan.K

2 turns and no more drop. Interesting... Are you sure your muffler or cylinder are stock? Does your MS260 have the 44mm or the 44.7mm piston?

Put the screen back in, then tach it...