Stihl MS 270 Issues

[MiModRacer]

Love the saw but its giving me an issue. When its cold, will start & run provided I keep it at 1/2 throttle. As soon as I let off on it it will stall & won't start unless I leave it alone for a few hours.

So I started out with, New gas, New Plug, Rebuilt the carb, Cked the fuel line to Carb for cracks & Still nothing different. It pulses the carb directly off the intake barrel of the carb on this model so its not a cracked pulse line.

From there, I pulled the coil off cleaned the contact points on the coil ( ele ignition) & on the flywheel, re-air gapped it correctly. Unhooked the kill/on/off from the equation & no spark at first. Then after a few pulls it mysteriously started to spark again , even with on/off hooked up. So by this time again it had been a few hours since it last ran so it was cooled off. Put it on Choke, barked on first pull, took it off choke & again it ran until I let it drop down to near idle. It then stopped, I pulled plug & no spark & I'm sure 3 hours from now it will start again & do the same thing. Questions,

1. Sounds like a coil to me but surprised I can keep it running if I keep it fairly well reved up.

2. In the carb rebuild process I pulled the orange plastic restriction caps off the L & H jets...So I could clean those needle holes. ... I found the L jet was way richer than the factory spec like a full turn richer ? I thought those plastic caps would keep those jets from turning on their own. With them out now , do I still stay with the factory settings of L-jet @ 1/4 turn out & H-jet @ 3/4 turn out.. or does removing the plastic cap restriction settings actually allow you see the real settings to run which I did write down. High jet was 7/8 of a turn at least & Low Jet was like 1 1/4 ????????? Anybody else find this type of scenario when they cked after pulling those orange caps off ?

 

[Fish]

They are called "limiter" caps to limit the amount the homeowner can adjust the carb, with them removed, turn both screws in until lightly seated, then back the high speed 1 1/8 turns out, the low 1 1/4, use this as a starting point, if it is not even close, then you should go back into the carb first.

 

[MiModRacer]

yep, thats where I thought I should start on the jetting for safety reasons-----last known safe place, Thanks for your input on that. She is fat for sure up high at the moment but I'm wondering if half of that isn't the coil breaking down. Coil cold ----Spark . Coil run for a minute----no spark. Why it runs ???? Low speed side of the coil going off once heated up & High just hanging on at high rpms er what ??????

 

[Fish]

I doubt it is the coil, but every now and then you get a real squirrelly one. Keep in mind, if you are on the look for another coil, although the ms270 and the ms280 are pretty much identical, most of the ms280s have a different ignition system, so the parts are different.

 

[SawTroll]

....

2. In the carb rebuild process I pulled the orange plastic restriction caps off the L & H jets...So I could clean those needle holes. ... I found the L jet was way richer than the factory spec like a full turn richer ? I thought those plastic caps would keep those jets from turning on their own. With them out now , do I still stay with the factory settings of L-jet @ 1/4 turn out & H-jet @ 3/4 turn out.. or does removing the plastic cap restriction settings actually allow you see the real settings to run which I did write down. High jet was 7/8 of a turn at least & Low Jet was like 1 1/4 ????????? Anybody else find this type of scenario when they cked after pulling those orange caps off ?

If that is what is printed on a label on the saw, it likely is how much you can move the screws with the limiters in place - not the basic setting with the limiters off.

 

[Whiskers]

When I first got my 270 it had 2 issues...

1. No Spark, The spring connector in the plug boot had come unattached from the plug wire. There's an outside chance this is an issue for you.

2. The carb boot was cracked in one of the folds. This is a major issue on this model due to the av setup, and if the saws got much run time on it, it's probably cracked and worth a peek.

 

[MiModRacer]

Spark Plug boot, I did have an issue with that coming loose a few weeks ago, Thought I had a real serious issue but somehow it had just poped up( disconnected) So I pushed it back down & it ran normal... Thats worth checking into. So what do you recommend ? , Split it down the middle & Cut it off & install a new one ? The Spark plug wire is about as short as it can be so I'd have to be careful about that. Is that a resistor cap & if so, any spec on what I'm looking for in the resistance dept ?

I appreciate all of you giving me ideas in an attempt to help.

My coil reads 1131 1301 A
AV 1133
504
Cked around earlier today on a replacement online, Stihl dealer says $70 & not seeing much better deal than that

Just spun it cold---- no spark

 

[Whiskers]

The plug boot has 3 parts that fit together.
1. The plug wire.
2. Spring terminal (or whatever the heck it's called)
3. Rubber boot.

The spring terminal has a pointed end that pushes into the plug wire and then fits into the boot. If the pointed end pulls out of the wire you will end up without spark.

To disassemble - Through the large hole in the plug boot grab the spring terminal with needle nose plyers and pull it out. If it's disconnected from the plug wire it will come out by itself if its still attached the plug wire will come with it.

To reasemble - Push the plug wire through the plug boot. In the small hole and out the big hole. Attach the Spring terminal to the plug wire by pushing the barb into the center of the wire. Pull the spring terminal back through the big hole in the boot. I find wrapping the spring terminal lead and plug wire with a bit of electrical tape or heat shrink helps keep it in place when I'm trying to get it back in the boot. A little bit of grease will also help things slide back together.

Hope this helps, it's a lot of words to describe a pretty simple process.

 

[Rookie1]

The spark plug boot is just a coiled up wire with a sharp end poked into the solid spark plug wire. A little tricky to put together but I would pull it apart and check or replace coiled piece.

 

[MiModRacer]

Ok an update, I replaced the boot on the spark plug & I now have spark again ( At least for the moment !!!) Dealer says ( didn't see the saw) but buy what I described the way it was running said that it sounded like an air leak. Handed me a carb boot ( not for free) I went back home took the top cover off, The rewind off & the carb & that stuff off to get a better look at the carb boot. Can't say that I can see a crack but I can't verify that their isn't one either at this point. I guess its a fairly common issue on this model saw.

My current question is what do I need to tear apart now to get to the boot to get it off & back on . I see two possible options to getting the required plastic off,

1. Pull the flywheel & ignition module off & spin or remove that plastic piece which contains the chain oiler tank ( ??? Is the flywheel nut a Counter clockwise tightening nut)

2. or what I would call removing the the back half of the saw, ( this is the anti vibe model) so I'd half to remove the brake handle, the saw handle & various other bolts to on the side & underneath. ????????????

The boot where it connects to the cyl either has either a hose clamp or a factory plastic zip tie holding it on . It appears to be a zip tie & although I may be able to get the boot off without further dis-assembly, I'm not convinced I can get the new one on solid & zip tied or what ever that clamp is with out further taking this saw apart. Anybody ever done this on this saw ?

 

[Whiskers]

The crack in the intake boot won't be visible until you take it off. It cracks down in the fold of the boot closest to the cylinder. The easiest way is to remove the rear handle that wraps under the saw, you'll have to take off the top handle, but shouldn't have to mess with the brake. There's a thread called "The beg for manuals" thread if you need a workshop manual. It will explain the removal process better than I can.

 

[MiModRacer]

Thanks Whiskers for the info. I found the Thread you mentioned, problem is there are 1187 pages to it. Is there some of search option (within that thread) to find the manual I'd be looking for ?

 

[Whiskers]

Just post at the end that you need a MS270 manual.

 

[MiModRacer]

Ok, I think I see how that Thread works, I'll post, Thanks.

 

[MiModRacer]

Latest update, Thanks Hogwild1 for hooking me up ... Got saw torn apart to ck Carb boot & nothing wrong with it, Will ck pulse line thats right by the boot & start reassembly today. Did find from the info I was sent that I might have the ign air gap set to tight. Will correct that when putting back together. It was an interesting tear down though, my background in 2 strokes is open mod drag racing snowmobiles. Kinda impressed with the engineering on these saws to get so much done in such a small package. Stay tuned for an update once I get it back together.

 

[MiModRacer]

Well put back together, W/ new spark plug boot & associated spring connector for spark plug. Cleaned coil & motor where coil mounts to motor & had previously cleaned coil & flywheel contact points. Had new plug too. Had Kill wires disconnected. Spun motor & saw spark. Walked away , came back & spun again, no spark. Ordered coil, waiting for it to come in.. I know its pretty unusual to lose a coil & I sure hope thats it. If thats it and I had to guess why it happened I would point to this---- a few weeks earlier, the saw started to run crappy & I found that the spark plug boot had somehow wiggled lose from the plug. Pushed it back on & the saw ran fine. I think for what ever period of time it ran ok prior to me discovering this could have damaged the coil, because it was straining to discharge its voltage due to a loose connection to the plug. Stay tuned, coil is supposed to be in tomorrow.

 

[MiModRacer]

Installed new Coil today & it fixed the sawuttahere2: Thank you guys for your help !

 

[Rookie1]

Good to hear you fixed it! I just picked up a 270 and had to put a new carburetor on it. I also bored out the hole in the muffler and put the spark screen back on. Now all I need to do is find some wood to try it out on.:msp_biggrin: