Stihl MS280 info

[bikerbill2021]

Hey everyone

New to the site, was hoping I could get some more info and some assistance with this Stihl MS280 I picked up recently.

A little background, I was looking for something to replace this crappy Poulan I found outside a dumpster one day and got it running for a season, but got fed up with its notorious hard starting and unreliability. I really only needed a saw for camping once or so a month in the summer seasons. Always heard good things about Stihl, so I started looking for a good used one. I bought this MS280 off a fella who stated he had it just gone through, new top end, bar and chain etc, seemed like a good deal so I grabbed it. Saw seemed a little stubborn to start, and somewhat boggy until it warmed up, but no where near as bad or tricky as that Poulan I had, and seemed to run strong, so I chalked it up to it being a bigger saw and a big older/cold blooded.

Now, I live down in Phoenix at about 1200 ASL, but when I camp in the summer seasons I head up north, which can vary in altitude 5-7000 ASL, as well as the occasional thunderstorm making things damp, so first trip out was a toss up if it would run properly or not, and sadly it fought me most of the time to even start. When I did get it running, I had to keep it alive and sort of "build up" to full speed for lack of a better term, If I stabbed the throttle at all it would bog and die, wouldn't idle, and eventually would die all together and just refuse to start at all. This most recent trip I was able to get it running for a bit, but eventually died as it had in the past and refused to restart, and I noticed what sounded like the fuel boiling in the bowl of the carb, if you clicked the choke on that boiling became much more pronounced. Feels like I'm using that damn Poulan all over again trying to start this thing repeatedly.

So, I come to you fine people at this site for some assistance. I'm new to chainsaws, but not to two strokes/engines (YZs, banshees etc) and am a mechanic by day, so anything with a motor is 2nd nature to me, but I do have some questions that would help clarify things. My biggest concern is did I buy the right saw for what I need? Like I said, I really only need it for the summer months when camping, and I'm only cutting up dead and down lumber for campfires, so I didn't really need a top of the line saw. That being said, I wanted something in the middle ground that would last me for a good while and obviously fire up and run when i needed it to. I was recommended to look for the 270/280/290 Stihl line, farm boss/wood boss etc. I didn't find a ton of info about the 280, but what I did find people said it was a fine saw and sounded like it would do the job fine. I thought about maybe one of those battery saws, but thats sacrilege in my eyes, plus I can already hear the heckling from my friends

If this is the right saw, then my 2nd question is tuning this thing properly at the elevation I'm currently at for the higher elevations I camp at, or just tuning this thing properly at all. I haven't really gone through the thing like checking compression and what not, pretty much took the guys word and threw some oil and fuel in it and fired it up. I use ethanol free 93 octane 50:1 fuel in it (those premixed fuel cans, I believe I have the Red Armor brand in it right now), and drain it when I'm done using it. So if there are any tips on how to go about tuning this specific saw that would be great, Ive read a bit on generic chain saw tuning, doesn't look like I need a special tool to tune it either from looking at the set screws.

I know some two strokes/saws are very picky about their starting procedures (my YZ can be a picky snob some times), but I don't think thats my problem. Chain brake on, Full choke, pull till it tries to fire, half choke, pull till it fires, let it idle for a bit, kick choke and brake off and should be good. My buddy has several Stihls and they all fire up pretty much first pull for him and purr away until they are ready to shred through some wood.

Thanks everyone, apologies for the novel, just trying to give as much info as I can. Any help would be greatly appreciated!

The saw in question

 

[Chainmale]

I'm sure someone with a bit more experience will be able to give some solutions a bit more specific to your problem, but with it dying under throttle the first things I'd check would be:
Perished fuel hose (can appear fine at first glance but can be enough to suck air without leaking)
Fuel pickup/ filter (in tank)
Tank vent (small valve in tank housing)
Impulse line ( rubber hose from carb to engine)
These are some of the easier/first things to check with dying under throttle but don't think it would be hard to restart after it dies with these problems. I could be wrong.
Probably a be a bit more saw than you need for camping firewood but if you're not tight on space it'll be great. Good mid size saw

 

[Wood Doctor]

Wading through all your text, I believe you have a running saw. Seems like all you need is an Owner's Manual. Check the Beg for Manuals sticky thread here and request one. I believe instructions for carb tuning the 280 are in there. It's not likely to be much different than the 028 AV:

 

[bikerbill2021]

I'm sure someone with a bit more experience will be able to give some solutions a bit more specific to your problem, but with it dying under throttle the first things I'd check would be:
Perished fuel hose (can appear fine at first glance but can be enough to suck air without leaking)
Fuel pickup/ filter (in tank)
Tank vent (small valve in tank housing)
Impulse line ( rubber hose from carb to engine)
These are some of the easier/first things to check with dying under throttle but don't think it would be hard to restart after it dies with these problems. I could be wrong.
Probably a be a bit more saw than you need for camping firewood but if you're not tight on space it'll be great. Good mid size saw

Wading through all your text, I believe you have a running saw. Seems like all you need is an Owner's Manual. Check the Beg for Manuals sticky thread here and request one. I believe instructions for carb tuning the 280 are in there. It's not likely to be much different than the 028 AV:

Excellent, thanks fellas, put in a request over on the beg for manuals thread, ill check into some of those things listed here as well

 

[Stihldoc]

The 280 is a nice saw. Low production numbers. so there aren't too many out there. I see several common issues with this series of saws and all of them are age-related. As previously said, the fuel hoses are problematic- just replace it! the -280 uses the MS 200T (1129) fuel hose. The Walbro HD carb is nearly bulletproof, but diaphragms still get hard with age. Install an ORIGINAL Walbro kit (about $10). If your saw has Intelligent Engine Management (IEM), it has a solenoid for high speed fuel delivery. Don't be scared of IEM- it generally works really well.
The -280 is a solid saw and generally needs only basic fuel system work to make it run well.

 

[bikerbill2021]

The 280 is a nice saw. Low production numbers. so there aren't too many out there. I see several common issues with this series of saws and all of them are age-related. As previously said, the fuel hoses are problematic- just replace it! the -280 uses the MS 200T (1129) fuel hose. The Walbro HD carb is nearly bulletproof, but diaphragms still get hard with age. Install an ORIGINAL Walbro kit (about $10). If your saw has Intelligent Engine Management (IEM), it has a solenoid for high speed fuel delivery. Don't be scared of IEM- it generally works really well.
The -280 is a solid saw and generally needs only basic fuel system work to make it run well.

Great info, thanks. From what I was told this thing was overhauled top to toe, but ill still check into the fuel lines and other things mentioned. Do you know if there is a way to determine what model or what my saw is equipped with such as the IEM and what not? Maybe where said solenoid is located/appearance? it'd be great to pin down even the year it was made and what not so I can get a better grasp on understanding it and what it has in it.

Are these 280s still a bear to start even after tuned right? Theres no fuel primer on it, so I'd assume it would still take 5-10 pulls to get her running even with it set up properly

 

[DND 9000]

If you have a MS 280 with the intelligent engine management your carb has only 2 adjusting screws, the LA and L. That`s an easy way to tell this, otherwise you have 3 adjusting screws.

 

[a. palmer jr.]

I have a 280 and believe me you can make it into a good running saw if you get the adjustments right..The only drawback is that it's not a common enough model and parts are a little harder to find than some Stihl models..

 

[bikerbill2021]

If you have a MS 280 with the intelligent engine management your carb has only 2 adjusting screws, the LA and L. That`s an easy way to tell this, otherwise you have 3 adjusting screws.

Gotcha, then mine indeed has the IEM system on it, as it only has the LA and L adjusting screws. So with this IEM system, is there no adjustment to the high speed? Only low and idle? I got a manual from the Beg for manuals thread, and there is no mention of the IEM that I can find in it. Also, the carb adjust section shows the version without it, so there is the 3 adjusting screws in the diagram, LA, L, and H. Forgive my ignorance, but the I like to know as much as possible about anything with an engine in my stable, even if its the most mundane things, gives me a better understanding of its functions.

I have a 280 and believe me you can make it into a good running saw if you get the adjustments right..The only drawback is that it's not a common enough model and parts are a little harder to find than some Stihl models..

Good to know, I figured Id be able to at the least tweek this into a solid saw that would last me years, thats the hope anyways. Off topic but I just noticed your avatar, haha I used to be big into those old mark 3 VWs, I remember seeing that pic years ago, brought back some memories!

 

[a. palmer jr.]

Yeah, I can't remember where I saw this avatar I've been using it here for several years..

 

[DND 9000]

There is no adjustment for the high speed. You can go through the calibration phase on this if you have fitted a new ignition module or if you haven`t a good performance. Start the saw and give full throttle for at least 10sec, after that let it idle for at least 10sec, again full throttle for at least 10 sec and again idle for at least 10 sec. Now it should be calibrated. If you use the saw, after a few minutes and several regulating sequences the microprocessor will reach the optimal setting. Tuning on the L and LA screw is done as before like on all other traditional diaphragm carburetors.

 

[bikerbill2021]

There is no adjustment for the high speed. You can go through the calibration phase on this if you have fitted a new ignition module or if you haven`t a good performance. Start the saw and give full throttle for at least 10sec, after that let it idle for at least 10sec, again full throttle for at least 10 sec and again idle for at least 10 sec. Now it should be calibrated. If you use the saw, after a few minutes and several regulating sequences the microprocessor will reach the optimal setting. Tuning on the L and LA screw is done as before like on all other traditional diaphragm carburetors.

Excellent good to know, thanks for the info. I take it the calibration should be done with the saw warmed up?

Ive been reading up more on the IEM and the 280 in general, I've got to fix a leak on the bar oil tank, which from the parts diagram looks as though there is a seal that seats between the tank and engine case, so I had planned on tearing into it this weekend, checking everything mentioned in this thread, as well as opening up the muffler a bit I.E. muffler mod it to help it breath a bit better. From what I've read the 280 with the IEM like mine do well with that mod, so thats my plan as of now. Thanks for all the help and info everyone!

 

[a. palmer jr.]

Mine's just got the normal carburetor on it so I'm not too versed on the other system.

 

[bikerbill2021]

Tore the saw apart this weekend to fix an oil leak on the tank seal, did the muffler mod to it, and gave it a once over. It looks like the fuel lines/filter/oil lines etc were indeed replaced by the PO after all, they look fairly new and are quite supple, should be good there. Is there a way to check the tank vent? Every time I pop the fuel cap off there is a pressure release, assuming thats normal as most fuel tanks are under some pressure. Gotta still check the diaphragm and impulse line for wear, but it does look like the PO did what he said he did and went through the saw, crank seals look brand new, even the inside of the cylinder/walls look fresh, so all looks good. So once I get this tank seal Ill get her back together and see if I can't get it running right.

 

[bikerbill2021]

So I got her all back together, gave everything a good once over, tore the carb apart and checked it all out/cleaned it, looked everything over, everything seems and looks good. Still a bear to start, doesnt like to idle, seems to run fine when laying into it, same as before. Played with the low/idle a bit before saying the hell with it.

I checked compression on it earlier on, and Im getting about 120 psi, which seems low for a recently refurbished saw, although im not sure what kind of numbers a fresh rebuild/new saw would be putting down. The gauge is a generic gauge I use for checking my dirtbike/quads etc, so its likely not 100% accurate, but its pretty close and has worked for me on my other machines.

 

[a. palmer jr.]

150 would be better. I was wondering if you could swap that carb for a conventional one..Some of the knock offs just cost around ten bucks on ebay..

 

[bikerbill2021]

150 would be better. I was wondering if you could swap that carb for a conventional one..Some of the knock offs just cost around ten bucks on ebay..

that may be something to consider, Ill look into it and see what I find

 

[a. palmer jr.]

I didn't see any on ebay right now but eventually one will show up if you keep looking..I think the carb is a Walbro HDC.

 

[DND 9000]

The carb is no Walbro HDC. It`s Walbro HD series. Older versions of the MS 280 without intelligent engine management used the HD-32 and machines with intelligent engine management are equipped with the HD-39.

 

[a. palmer jr.]

Yep, I see that. I was looking it up on ebay and the kit for the saw appears to be the same as the HDC but indeed they do call it the HD-32 and I think there's a third one, the HD-33. You might have to change the carb and ignition both to get the proper resuilts since they're wired together..