Chainsaw won't run right.

[CUduckreeper]

Replaced carb. No primer bulb. I put seafoam in it. Replaced fuel line and fuel pickup filter once. I don't have a compression tester but it seems to have decent compression judging by how hard it is to pull start with and without the plug and feeling the pressure at the spark plug hole with my thumb while I pull the rope.

I don't sell stuff.

It sounds to me like the carburetor is out of tune. I know you said you just replaced it but did you tune or try to tune the new carburetor.

[Redleg Camo]

Replaced fuel line and fuel pickup filter once.

When's the last time you replaced the fuel pick up line? Sounds like a carb/clogged jet issue to me but like i said, fuel pick up line is what caused my issues the last 2 times.

[BigBrother]

When I had the same problem, I blew out my air filter.

Gas engines have three legs. If they one of the three aint working, you aint got a gas engine.

[Relentlous]

Is the bar pinching the chain?

[BigBrother]

Is the bar pinching the chain?

Ohhhhh....

I didnt even think about that.

[Bownut]

Is the bar pinching the chain?

Or the sprocket at the tip of the bar. Take the bar and chain off and see what it'll do.

[Palmetto Bug]

I've tried two new carbs on it. There is no adjustment to them other than idle speed. I have replaced the fuel pickup tube, fuel filter, air filter and run it without the air filter. I'm going back through to see if a new part is defective. This is starting to feel like one of those wild goose chases when you put trust in a new part that came broken.

[ecu1984]

I've tried two new carbs on it. There is no adjustment to them other than idle speed. I have replaced the fuel pickup tube, fuel filter, air filter and run it without the air filter. I'm going back through to see if a new part is defective. This is starting to feel like one of those wild goose chases when you put trust in a new part that came broken.

It wont look like a regular air/idle adjustment screw
It will be a black plastic thingy with a weird indentation that is flush in the carb housing
Google "pac man" adjustment tool
Everyone one I have ever replaced needed adjusted out a little and then revvved right up
https://www.amazon.com/Carburetor-Ad...26513974&psc=1

[Phone Man]

Buy an echo

[CUduckreeper]

After a little research it does appear that the stock carburetor for the ms170 is non adjustable, which seems ridiculous to me. I did see where they make an aftermarket adjustable carburetor you can replace the original with. Your original description of the problem still sounds like a carburetor (fuel to air mixture) problem. I would think that replacing the carburetor would fix the problem. Plus you already stated you replaced the fuel line and air filter so I’m a little stumped. Let us know how the double checking of new parts goes.

[SaltMuck]

Sell it and buy a new one. Cheaper in the long run.

[bdunc]

Part # 1130-120-0603. C1q s57h. Is your part #. Don’t buy a aftermarket carb. If less than a year old have the dealer you bought it from warranty it if it’s the carb.

[ecu1984]

if it has bad compression, it can idle and run great but will fall flat on it's face when a load is put on it

[acebasinman]

Have you done what bownut said?

[Palmetto Bug]

Have you done what bownut said?

I can spin the chain by hand very easily.

I'm looking at getting an OEM carb like bdunc suggested.

I'll probably also pick up a compression gauge since I have an excuse to buy a new tool.

I have a few other chainsaws but this one is a handy size and has had damn near everything replaced so far. Now it has become a challenge.

[Palmetto Bug]

DRDUCK wins the "KRT of Chainsaws" award. I got my new compression tester and the chainsaw is only registering about 80 psi. Now I need to order a new top end.

[DRDUCK]

I kinda figured a broke ring or a scored cyl. wall I got a sthil i been running for 43 years and ain't touched it except a plug or 2. Of course that is when they were made in Sweden or somewhere over there with chrome rings and real parts.

[ecu1984]

DRDUCK wins the "KRT of Chainsaws" award. I got my new compression tester and the chainsaw is only registering about 80 psi. Now I need to order a new top end.

Decarb it first, warm it up and then pull plug and fill cylinder with seafoam.
Then after a long while, pull it a few times with plug out to blow the seafoam out of the cylinder
then mix a heavy dose of seafoam and run it for awhile......will smoke like crazy.
Then recheck compression. May have a ton of carbon buildup on valves and piston/rings.
Seen it a hundred times and then compression is restored. I would take my Milwaukee camera scope
and also look at piston top and cylinder walls for damage if you have one. Probably carbon stuck a ring

[turbo]

After a little research it does appear that the stock carburetor for the ms170 is non adjustable, which seems ridiculous to me. I did see where they make an aftermarket adjustable carburetor you can replace the original with. Your original description of the problem still sounds like a carburetor (fuel to air mixture) problem. I would think that replacing the carburetor would fix the problem. Plus you already stated you replaced the fuel line and air filter so I’m a little stumped. Let us know how the double checking of new parts goes.

Nearly everything is "non adjustable" these days.

Just pick the plastic filler off the the adjuster and adjust away. Another California addition to small engines.

I have a perfectly modified flat head for adjusting carbs. Long neck flat head with the sides ground down to fit. I stick it in my back pocket the first time I use equipment every year and tune her up a bit as I go. Usually don't have issues after that.


**To ECU's point of valves. What valves do you speak of? It's a 2stroke motor, homie. They're reeds and unlikely to be "carbon'd up".

[ecu1984]

Nearly everything is "non adjustable" these days.

Just pick the plastic filler off the the adjuster and adjust away. Another California addition to small engines.

I have a perfectly modified flat head for adjusting carbs. Long neck flat head with the sides ground down to fit. I stick it in my back pocket the first time I use equipment every year and tune her up a bit as I go. Usually don't have issues after that.


**To ECU's point of valves. What valves do you speak of? It's a 2stroke motor, homie. They're reeds and unlikely to be "carbon'd up".

ah, true
but even more reason for rings to be carboned up, particularly if running heavy mix and short periods of use