Andrew Massey
ArboristSite Lurker
can you please post a link to the carb you bought
Stihl MS 170 Mod Oh Yeah Baby!
- Thread starter tmessenger
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Ando81
ArboristSite Operative
Ando81
ArboristSite Operative
I haven’t put the saw into a solid piece of wood yet but it sounds much sweeter just revving it without load. Like someone posted earlier, it may be a bit harder to start without having the half choke option like the original carby but I think I can live with it. I hope to use the saw on Saturday so I will be able to share my findings then, stay “tuned” [emoji1787]
Andrew Massey
ArboristSite Lurker
Thank you, This was the exact carb I was looking at too, Look forward to seeing how you go, Whats the go with the choke as in what happens when you put it in the half choke position? its just in run?
Ando81
ArboristSite Operative
The choke seems to jump off the second notch and goes straight to run. I didn’t take a lot of time to look at it enough but I’m thinking that the choke flap lever is slightly different to original carb and pulls the start lever straight up to run instead of stopping half way. It might need further inspection on the weekend.
Andrew Massey
ArboristSite Lurker
All good mate just trying to get a mental picture of what happens, Sounds like its definitely worth it though! I was looking at the wt215 as my ms170 was bogging down at wot, But pulled the carb apart and cleaned it out and now its all good but is running slightly too rich and no longer pulls the rpms it did and cuts no where as fast so might buy one and throw it on just for the adjustability and tuning benefits!
Called the dealer near me and a genuine wt215 is $112.50, not worth it when I payed $150 for the saw
Called the dealer near me and a genuine wt215 is $112.50, not worth it when I payed $150 for the saw
Ando81
ArboristSite Operative
Well after giving my setup a tune I tried it in some very damp greybox and it seemed to bog down a little. I had my 14” tungsten tipped chain so figured that it wasn’t a really practical test for it. I tried it in a piece of very dry ironbark with the tungsten chain and it performed well. I wouldn’t say a huge improvement in power but a small improvement. I actually got the choke to work on the half choke and it started up really well. I’ll try to get to the muffler mod and another tune tomorrow to see if anything changes.
How much did you file off for the advance ? No issues with detonation I trust
Hey, All!
So glad I found this thread! Based on its contents, I ordered an OEM Stihl W215 carb. I love my little 170, but have always found her slightly gutless. In general, I try to match the saw to the job, and use the smallest one possible. Can't wait to do the mods.
Also found this video on YT, in which the poster did 6 mods to his 170. Take a look:
Hope this helps!
Mike
So glad I found this thread! Based on its contents, I ordered an OEM Stihl W215 carb. I love my little 170, but have always found her slightly gutless. In general, I try to match the saw to the job, and use the smallest one possible. Can't wait to do the mods.
Also found this video on YT, in which the poster did 6 mods to his 170. Take a look:
Hope this helps!
Mike
He
How did the carby mod go? Did you also remove the brass plug, and fill the left hole? Yes, agreed! The first mod I did was the side tensioner - if I wanted to struggle with a fiddly little screw next to the bar, I would have bought a Husky!!!
Thanks,
Mike
Hey, Ando81!!
How did the carby mod go? Did you also remove the brass plug, and fill the left hole? Yes, agreed! The first mod I did was the side tensioner - if I wanted to struggle with a fiddly little screw next to the bar, I would have bought a Husky!!!
Thanks,
Mike
cranman1951
ArboristSite Operative
Very interesting thread! The smallest Sthil I've used is a 230 and it was one of the handiest saws I've ever run.
Ando81
ArboristSite Operative
That’s right, I had all of the tips from here how to prepare the new carb to suit my 170. It’s running great but I’ve tuned it to be slightly rich just to be safe. It goes really well.
would you use some JB weld as long as it doesn't run down into the carb or would a dab of silicon sealant work?
KostasVolos
ArboristSite Operative
I used a tattoo ink cap ( 11 mm diameter at bottom ) and plugged the vacuum passage hole at backside of the air box ( the upper one where the metering chamber snorkel of the carb plugs into .It plugs air tightly.
Tattoo ink caps
https://www.amazon.com/UPTATSUPPLY-Permanent-Pigment-Container-Accessory/dp/B07RZ48XR1
You can just visit a local tattoo shop and ask for some .They are so cheap that probably they will give you few free of charge.
The upper opening (vacuum) is sealed air tight with a tattoo ink cap ( 11mm bottom dia)
...Or alternatively ,the air intake snorkel insert can be removed and the vacuum intake can be sealed with epoxy/silicone ,like shown at this photo.
And since we mentioned the insert ,a bit
of Dremel work will " open up " the air intake ,without having to discard the insert ( which will impact the sealing of the air filters oval center opening,if so ). Remove the vertical little "flap" and drill out a nice big hole on top of the insert ,as shown .
Of course all the above can only be done ,in conjunction with an adjustable carb mod ( Walbro WT-215 or clone ) .
Note : Stihl guarantee is void after these mods !
So here is my "project". I picked up a 170 at a pawn shop. It was very clean with no usage wear on it and only a little sawdust gunk around the chain. It started right up and seemed to run ok for the brief time i could run it at the shop. Paid 125 for it, and felt pretty good about it. My 391 needed a companion!
Well......then the fun began. The chain was so dull it would hardly grove the bark. A quick sharpen and it was better but replaced the chain anyway. It would run great for about 5 minutes, but would then die every time you let up on the throttle. Tune up time. Did full tune up, filters, plug, new gas, added bucking teeth. Now ran good. Got an opportunity to use for real after storm took several big limbs down on the property. It ran great for 20 minutes or so, then started losing power and i swear it felt like a rod knock! Shut it down and used a different saw to finish the job. I took to my local Stihl dealer and said give it a once over, it don't feel right. Yup. FUBAR! One of the rod bearings disassembled itself! The inner race was still on the crank, the bearings and outer race pieces were free in the block! He tells me other than that the rest of the saw looks brand new. Verdict- would cost more to repair than buy a replacement. I have called Stihl as this seems to be a quality control issue not a maintenance issue. We will see what they will do for me. Not holding my breath.
In the mean time, it became time to Frankensaw this 170! I found a replacement engine on ebay. the 32cc MS180 aftermarket engine was purchased for 26 dollars, a 215 carb for 10 dollars, and a muffler mod to complete the ensemble. I am trying to decide if I should do the timing advance. Looking for some advice on that. Is it worth it and best way to do so if I do. Modded the carb by pulling the impulse plug (this one had a solid brass plug that I needed to drill and use an easyout to remove!) and block the side hole next to it with silicone. Any thoughts on anything else while its apart?
If this works out, I will still be under the cost of a box stock 170!
Well......then the fun began. The chain was so dull it would hardly grove the bark. A quick sharpen and it was better but replaced the chain anyway. It would run great for about 5 minutes, but would then die every time you let up on the throttle. Tune up time. Did full tune up, filters, plug, new gas, added bucking teeth. Now ran good. Got an opportunity to use for real after storm took several big limbs down on the property. It ran great for 20 minutes or so, then started losing power and i swear it felt like a rod knock! Shut it down and used a different saw to finish the job. I took to my local Stihl dealer and said give it a once over, it don't feel right. Yup. FUBAR! One of the rod bearings disassembled itself! The inner race was still on the crank, the bearings and outer race pieces were free in the block! He tells me other than that the rest of the saw looks brand new. Verdict- would cost more to repair than buy a replacement. I have called Stihl as this seems to be a quality control issue not a maintenance issue. We will see what they will do for me. Not holding my breath.
In the mean time, it became time to Frankensaw this 170! I found a replacement engine on ebay. the 32cc MS180 aftermarket engine was purchased for 26 dollars, a 215 carb for 10 dollars, and a muffler mod to complete the ensemble. I am trying to decide if I should do the timing advance. Looking for some advice on that. Is it worth it and best way to do so if I do. Modded the carb by pulling the impulse plug (this one had a solid brass plug that I needed to drill and use an easyout to remove!) and block the side hole next to it with silicone. Any thoughts on anything else while its apart?
If this works out, I will still be under the cost of a box stock 170!
KostasVolos
ArboristSite Operative
Do not forget to place a small screw in the slot of the trigger lever ( you will have to open up the handle -need a Torx 20 ) as a
"stop" so you can achieve WOT with the adjustable carb.Do not bend the throttle wire for that purpose !
The screw should be placed at the far end of the slot so that the throttle wire should rest on it at WOT.This way you take off the slack of the trigger slot and the throttle wire can fully engage the carb throttle lever .
Replace the pos Bosch USR 4 AC
spark plug which comes with the saw with a NGK CMR6H one .
If you are using gasoline with ethanol ,the carb pump diaphragm should be of the acetate kind or the Teflon one.And have a spare metering diaphragm ,since its made from PIB and ethanol slowly will disintegrate it.
Ethanol will also disintegrate the fuel line if it is the old type ( black color ). That could cause a sudden lean situation .
Replace with the new ( green color ) fuel line which is ethanol resistant .
And an aside useless piece of info :
Stihl offers two different bucking teeth for the MS170/MS180 .
Edit:
Time advancing generally "skews" the power towards low and/or mid rpm ranges ,while
retarding timing "skews" the power output towards higher rpm.
Being stock the MS170/180 has a max power output ( 1.6 hp /1.9hp ) at 10,000 rpm.With max rpm at 14,000.
I think that those small engine saws can benefit from their small sized pistons ( which can operate at higher linear speeds than larger ones ) and can achieve pretty high chain rotation speeds.Their nature makes them to be screamers .But they lack torque .Advancing the timing will
make the engine to output it's peak power lower than 10,000 rpm .Meaning at lower chain rotation speeds.That is
somewhat counterproductive with the whole nature of this low cc 2Τ engine .
The saw lacks torque( from birth ... ) but outputs its peak
power at high chain rotation speeds. And should be operated based on that "asset" so to speak.
adedeluca
ArboristSite Lurker
Excellent
