Stihl MS170 Low On Power-Fixed!

A look at how you can save a trip to your mechanic with this simple repair that will bring back the power in your Stihl chainsaw.
#smallenginerepair

[@andrewcornford2306]

I've watched hundreds of chainsaw repair videos, this was great. The way your in the window talking to us and being able to see what's happening.

[@TheGreasyShopRag]

Thanks and thanks for watching!

[@thomascaldwell657]

Just found your channel when my 170 wouldn't rev up. Burned the build-up off the spark arrestor and it's running like new. Thank you!

[@TheGreasyShopRag]

You're welcome. Thanks for watching!

[@joshhardy9993]

I just wanna say thanks mate I nearly went and bought a new one. All that was wrong was the spark arrestor needed cleaning. I’ve had it for about 10years. Running great now.

[@TheGreasyShopRag]

Glad to hear it. Thanks for watching!

[@Schroederhillsidefarm]

That was a great video! I have the same saw and couldn’t figure out why it was not running at full power. The Spark arrester was plugged up. I burnt it clean and it is running great! Thanks!

[@TheGreasyShopRag]

You're welcome and thanks for watching!

[@asedcopf]

spark arrestor was air tight - burnt it off runs like a dream - thanks very much.

[@TheGreasyShopRag]

Thanks for watching!

[@ianmorrison8348]

Fantastic tip just cleared the exhaust screen😊

[@TheGreasyShopRag]

It should run better now!

[@user-rc7cw6cc8y]

Thanks Greasy shop rag! gonna try to clean/change arrestor! Thanks again for the tip(s)

[@TheGreasyShopRag]

Thanks for watching!

[@Gary67242]

my 170 never had much power right out of the store lol...thumbs up

[@TheGreasyShopRag]

Lol, ya none of them do. Thats not a dig on stihl, just an observation.

[@alnavas1265]

Thank YOU. As the comment below from Josh. Same here...thank YOU.

[@TheGreasyShopRag]

You're welcome.

[@user-zd3dz9qi3b]

Thanks, spark arester clean and runs like new!

[@TheGreasyShopRag]

Thanks for watching!

[@aerotech1bob]

Great information

[@TheGreasyShopRag]

Thanks for watching!

[@tuckerandi]

Great informative video

[@TheGreasyShopRag]

Thanks for watching!

[@foldingchaise8387]

Thanks, good video !!!!

[@TheGreasyShopRag]

Thanks for watching!

[@w6qd]

As the saw the took the traditional take down to the Greasy Rag I observed the shiny and clean top cover, starter assembly, and not a scratch on the bar. I threw down my money that the owner stored the saw with gas in it for an extended amount of time. This saw didn't look like it had much time on it. Well, I guessed wrong, it almost looked like the saw was run on 36:1 and was never operated at WOT. What a gooey mess after the muffler was removed.

[@TheGreasyShopRag]

Theres a lot of people that think way more oil is better. Some people also think they are babying their saw by not running it wide open. They learn the truth when they are at the front counter paying the repair bill.

[@mariocavazos5169]

Really enjoyed the video. Learned a lot from it. But I have a question. The Vacuum Brake bleeder you where using on the fuel line, at the beginning of the video, was that to check for air leaks?

[@TheGreasyShopRag]

That tool is the MityVac MV8500 and can pull vaccuum or create pressure. I put 10 pounds of pressure on the fuel line to check for leaks in the line and carb.

[@B44SB66]

whenever a two cycle weedeater chainsaw or other yard implement is low on power or hard to start but has adequate compression as determined by the recoil response don’t waste your time on other remedies and go directly to the muffler and remove it and check the spark arrestor and if the saw has been stored for some time look for a mud Dobber nest or blockage in the muffler outlet

[@TheGreasyShopRag]

"Don't waste your time on other remedies" I disagree. A plugged air filter or fuel filter could give similar results. A tech should have a system in place where everything gets looked at so we aren't just fixing the result of a different problem.

[@timothycole3368]

Spark screens can get clogged up like that by half throttling alot.It doesn't allow all the oil to burn out of the fuel.Also if there's too much oil in the fuel this can happen.Hope this helps someone.God bless.

[@TheGreasyShopRag]

I'm more a believer that its the oil quality more than quantity that matters. I've seen a lot of 32:1 mixes that never plug the screen.

[@Kyle-bb9zp]

I really like this you tube name 😊😊

[@TheGreasyShopRag]

Thanks for watching!

[@tedneitzel]

Ya know in my 40 plus years of running a saw I've never plugged a spark arrestor screen. I've used them till the pretty much dissipated but Yes never clogged one! 40:1 mix always. Well 32:1 in earlier days but once oil started improving so much 40:1.

[@TheGreasyShopRag]

Ya those screens aren't a problem if you run the saw as intended.

[@steveriggenbach90]

I watch and also just listen to several times. Catch things missed before. Do you normally adjust carbs by tach or ear? How do you know if carb’s check valve is going bad? Thanks

[@TheGreasyShopRag]

The check valve is good or bad, not "going bad". If you look into the throat of the carb when hitting the primer bulb and you see fuel come out then the valve is bad. Theres a test that can be performed with a pressure gauge also. Stay tuned for that video. As far as tuning carbs, what you see in the videos is me just getting it close. After the video stops I take the equipment outside and do the final adjustment. Sometimes with the aid of a tach.

[@steveriggenbach90]

@@TheGreasyShopRag thank you. I like a load on it or best in the wood. Never knew about the primer bulb method. Used suck/draw test. Have been trying blocking a port and then test thru the other. Waiting for your video. Thanks again and take care.

[@luxbeci2]

What you use cleaner spray in Stihl chainsaw? Carburetor cleaner or Broke cleaner spray? I very interest yours repair videó gived me very much important information How need fix my Stihl 880 and Stihl 171. How you setting Stihl 170 carburetor? Only 1 setting bolt Jack and not 3 bolt Than I have Stihl 880 and Stihl 171 high and low and third bolt Jack set. Do you know change 3 bolt set carburetor? Walbro or Zama? Walbro more better, Zama Chinese not good

[@TheGreasyShopRag]

A fellow KZbinr named Tom has a great channel that goes in depth on a lot of your questions. He recently did a 170 carb video. Check him out: www.youtube.com/@VintageEngineRepairs

[@luxbeci2]

@@TheGreasyShopRag Thank you I follow this channel

[@alanshaw6161]

It's the Stihl brand oil that does it. There oil is really made for the 4 mix product line. Switch to Echo's Red Armor 2 stroke mix oil and you will never have to clean a spark arrest ever again. In fact Red Armor would clean it up in about 3-5 tanks....

[@TheGreasyShopRag]

Yes I like the red armor oil.

[@nathant3897]

Sweet I’ll try that next. Mine chokes out before higher rpm’s

[@TheGreasyShopRag]

Thanks for watching!

[@joeclemmons6505]

I don't have a torch: But I do have Coleman fuel; It takes about 45 minutes-1 hour to soak loose.

[@TheGreasyShopRag]

That works great at home but when you're doing back to back repairs and charging by the hour the torch works best. In the end, if you're cleaning it and reinstalling it then you're doing it right. Thanks for watching!

[@magicone9327]

Any diagnose for a 028 with new aftermarket top end, no air leaks, factory carb good, new aftermarket carb used as well, muffler clean, new fuel. Starts, runs and revs good until it’s put under load. Then it’s lacks power, reduce the force of cut pressure being applied and it seems to cut ok but not if it’s pushed into the wood. Tried different carb and no change, new fuel lines and filter. Tried with tank vent on and off with no difference. Looked at the intake timing against the exhaust timing. Correct with intake just opening and can’t see the exhaust top ring as yet. .325 lp chain 16” sharp. Haven’t done a compression test but it pulls with a good resistance. Haven’t done a squish test yet either so don’t know if there is a difference in pistons oem and aftermarket.

[@TheGreasyShopRag]

Does it have one of those funky air filters with a choke flap built into it? I've seen a weak spring allow that choke to be pulled closed during high speed operation.

[@magicone9327]

@@TheGreasyShopRag yes, but I have the symptoms with it removed. I have even looked at the ignition timing. Keyway is good. I have even hooked up remote fuel supply to see if it made a difference. Just finished an 021 and it cuts like a monster compared to the 028. I wish I had a different bar and chain as that hasn’t been removed from the variables.

[@mikesmith9781]

Great video, I have a problem with mine, it will start and run fine, BUT the (cow) that's a polite word, will not restart. leave it for a day or so and it starts. Any ideas

[@TheGreasyShopRag]

My first thought is that its flooding. Possibly a stiff metering diaphragm. How many pulls on full choke are you doing?

[@mikesmith9781]

@@TheGreasyShopRag thanks for getting back I would say 3 or 4 on chuck take spark plug out and it is wet sometimes

[@TheGreasyShopRag]

@@mikesmith9781 I don't want to lead you down the wrong path but if you know and test for consistent spark then its a fuel issue. Its easy for me to say open up the carb and look but I know thats a lot to ask if you've never done it.

[@mikesmith9781]

I'll have a look and and clean up carb, over the weekend, then see if I can start the cow .thanks I'll let you know

[@Vipex_134]

Why do they have spark arrestor screens?

[@TheGreasyShopRag]

To prevent a spark from exiting the exhaust and starting a forest fire.

[@Kyle-bb9zp]

I have the I have the same model I am not getting full throttle or wide open throttle. I have good fuel have not checked the spark plug yet. But now I see that you cleaned out the exhaust area. Mine actually has a lot of black build up on the outside of the exhaust. Could that be the problem maybe? Thanks again Kyle

[@TheGreasyShopRag]

plugged exhaust could be the problem but so many things could be the problem, starting with the throttle linkage.

[@Kyle-bb9zp]

@@TheGreasyShopRag I will check the exhaust first throttle seem to work good. Also check the spark plugs as well.

[@Kyle-bb9zp]

@@TheGreasyShopRag yep that was the problem worked awesome after that.

[@wayne69wayne69]

Are there reliable???

[@TheGreasyShopRag]

Like many saws, the reliability depends on the maintenance it gets, but generally speaking I would say yes.

[@wayne69wayne69]

@TheGreasyShopRag thanks am taking the ryobi back and getting the 170 ms 😁

[@brucenichols540]

I sold 'parts' for many years... The folks that always go for 'the cheap stuff' when buying Oil are the folks that are constantly having problems. Same with their Vehicles and Equipment... Quality Fuel, Oil & Filters cost FAR less than 'the cheap stuff'.

[@TheGreasyShopRag]

I couldn't agree more. A filter that doesn't "filter" isn't gonna do ya no good. My exception is hard goods that I can repair, weld or whatever if it breaks.

[@williambray4134]

Both a clogged air filter, clogged spark arrestor screen, and damaged piston, and cylinder will cause low power if the saw starts. My bet was the spark arrestor screen in this case.

[@TheGreasyShopRag]

I see this problem in small stihl equipment more than other brands. I wonder if its the oil or if the engines just don't get hot enough to keep the screen clean.

[@stihlhead3338]

I purchased a Stihl 036 from a guy on marketplace and I was supposed to pick it up at his local Stihl dealer, which I'll leave unnamed. I was told by the seller that it was at the dealer getting a once over. When I went in to pick it up I asked the tech if they had fired this thing up, does it run good? The tech replied everything was good runs awesome. Low and behold when I got home I fired it up it would not stay running, yada yada yada. Of course the spark arrestor was completely plugged like the one in the video. The moral of the story is when your paying good money to have a Stihl tech give your saw a once over you should feel assured that you're getting what you pay for. I can appreciate what you was saying about going the extra mile when you're working on a customers saw. Keep up the good work love your videos Man!

[@TheGreasyShopRag]

@@stihlhead3338 Thanks. I wonder what the relationship between the seller and the stihl dealer is? Did you tell the seller that the dealers idea of a once over probably didn't include a test run?

[@stihlhead3338]

@@TheGreasyShopRag I did, I messaged the seller and told him that he should get his money back if he paid for any services. I explained to him what the deal was with the saw, but I don't think he cared too much. Maybe the guy worked there, I don't know.

[@stihlhead3338]

@@TheGreasyShopRag well I have your attention, what kind of grease do you use on the oiler gear and needle bearings?

[@phantomshtter]

10 minutes of KZbin research, an old toothbrush, and a cup of gas would have fixed their problem. I can't stand people who have more money than sense. You'd be out a job without em though!😅 Bitchin tunes by the way boss man.🎸🎶

[@TheGreasyShopRag]

Thanks for watching!

[@dondig2617]

I wish teaching videos didn't have music you never see a hard rock band working on a small engine in their videos. Just saying!

[@TheGreasyShopRag]

I've been on and off with the music. The last few months doesn't have much and a few videos coming up do. At one point I considered no voice over and just the repair set to music. I guess I always thought these were just videos showing what I do and how I do it but I guess they are teaching videos. Thanks for watching and putting up with the music.

[@dondig2617]

I wasn't meaning that bad I thought it was great that you didn't have music is what I meant. Great video@@TheGreasyShopRag

[@TheGreasyShopRag]

@@dondig2617 Its all good. Just saying the whole music thing has been kinda a struggle for me.