Ms 180 rebuild with pictures.

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Have had nothing but problems with these.
I use chi walbro copies with both mixture screws and all ok.


Hey :) yes, I have noticed that these saws have slight hesitation in acceleration because they can’t be adjusted too. I guess as a homeowner saw less is more for the average joe!

Has you got a link to the carb from China? How much cheaper was it compared to a genuine Walbro? If it’s a few dollars I don’t mind sticking with genuine parts, some how though I doubt it is haha
 
That idle screw is just an air bleed adjustment, it should screw out, I think those have a reverse thread, either way, there is a reason it came to you in the condition its in, now the fun bit is finding out exactly why.
the idle circuit is mostly coverd by welsh plugs, and these need to be removed to effectively clean out the idle side.

The main jet, yes you unscrewed it, place some fuel hose over the main jet, make a seal, and then blow and suck, it should pop shut when you suck, and pop open when you blow, if you can draw back the main venturi valve is either needing cleaning, or damaged.

or replace with a walbro 215
see thread here about what to do, pg12 has good pics too
https://www.arboristsite.com/community/threads/ms180-adjustable-carb.74899/page-12
 
I think it was $39.
Got it from Paul at chainsaw parts Australia here in Launceston.
Got it from him because he is local and if anything is wrong he will make it right.
Search eBay for ms180 carburetor and look for the cpa logo.
Make sure it has the mixture screws.
As you can also get the zama like you already have.
Chris.
 
Carby Doctor has one for $28.50
Thanks for the heads up, I found it :) $28 is good if it works! So this is the correct one i’ll Need? I’ll have a read up re trans instruction link to making it fit :) if you could just confirm it’s correct i’ll Purchase it :)
 

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That idle screw is just an air bleed adjustment, it should screw out, I think those have a reverse thread, either way, there is a reason it came to you in the condition its in, now the fun bit is finding out exactly why.
the idle circuit is mostly coverd by welsh plugs, and these need to be removed to effectively clean out the idle side.

The main jet, yes you unscrewed it, place some fuel hose over the main jet, make a seal, and then blow and suck, it should pop shut when you suck, and pop open when you blow, if you can draw back the main venturi valve is either needing cleaning, or damaged.

or replace with a walbro 215
see thread here about what to do, pg12 has good pics too
https://www.arboristsite.com/community/threads/ms180-adjustable-carb.74899/page-12

You are spot on champ reverse thread, but won’t come all the way out :(.

I’ll try that suck blow thing for sure! (Did I just say that?!?!)

I need a tachometer next and they are EXPENSIVE! but it will be fun to learn to tune a saw :) especially as my fathers saw I’m getting will have adjustable carb!
 
Venturi works, no fuel line so used straw worked good! After doing it a number of times because it was satisfying hearing it open and close it got stuck so I had to blow quite firm. Now it’s twice as firm to blow than suck. So what is that thing opening and closing? Some sort of rubber flap ?
 

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Pressure/vacuum testing is a good way to know the seals are solid. If you don't have a mityvac tester, you could use a compressor turned down low to say 15psi & spray some soapy water around the crank seals, decomp etc looking for any bubbles.
 
The walbro clone mentioned can be gotten from ebay. It's the same carb they use for the MS250. I think I paid $10 CAD for it shipped from China.
 
Oooo! I have a ms 025 I wonder if that carb will fit in the ms 180 then?! It sounds too simple hah

Did the shipping take agessssss?

Best you read the threads on installing an MS 250 carb on a MS 170 or 180 BEFORE you go playing with your OEM 250 carb.
Take note of the impulse circuit and how one needs blocked and one opened- once configured to fit your 180, it will not work on your 250.
 
Best you read the threads on installing an MS 250 carb on a MS 170 or 180 BEFORE you go playing with your OEM 250 carb.
Take note of the impulse circuit and how one needs blocked and one opened- once configured to fit your 180, it will not work on your 250.

yep, Im with Bob on this one, slow down Tom, take a few deep breaths, relax, some things take time.
if your waiting on parts for one saw, start on the other (insert evil laughter here), but be careful you dont confuse yourself and try and put together a frankensaw by mixing up the parts. :)

You need to determine what caused this saw to arrive at the state that it came to you. pressure test on engine can be as simple as some bicycle rubber tube cut out where the valve is fixed to the tube and that snugged down over the exhaust or inlet, and gentle pressure applied, hit block with soapy water and brush , turn the crank, see how the seals and base is.

Dont assume anything, your doing an autopsy on the saw, so each and every part needs close attention, you will find the reason sooner or later, harlyt has posted pics before of the inlet manifold squashed and the impulse hole blocked from the deforming that took place.

Could just be poor fuel mix, poor use and lots of abuse. or something else.
 
Thanks for the heads up, I found it :) $28 is good if it works! So this is the correct one i’ll Need? I’ll have a read up re trans instruction link to making it fit :) if you could just confirm it’s correct i’ll Purchase it :)
Won't confirm any thing Tom.
As doing this has bitten me on the a$$ before. lol.
I "think" this correct.
Have to drill holes in plastics to access mixture screws.
I had to remove throttle linkage from trigger and fit to carb first as am carb has a hole not a slot for linkage.
 
Won't confirm any thing Tom.
As doing this has bitten me on the a$$ before. lol.
I "think" this correct.
Have to drill holes in plastics to access mixture screws.
I had to remove throttle linkage from trigger and fit to carb first as am carb has a hole not a slot for linkage.
Haha all good, yes quite right, if it wasn’t I wouldn’t “blame you” haha. That’s easy enough to remove the linkage though, that’s a score :)
 
Best you read the threads on installing an MS 250 carb on a MS 170 or 180 BEFORE you go playing with your OEM 250 carb.
Take note of the impulse circuit and how one needs blocked and one opened- once configured to fit your 180, it will not work on your 250.
Thanks Bob, yes I had a read of removing the brass plug and sealing the impulse hole :)

Thanks for sharing :)
 
yep, Im with Bob on this one, slow down Tom, take a few deep breaths, relax, some things take time.
if your waiting on parts for one saw, start on the other (insert evil laughter here), but be careful you dont confuse yourself and try and put together a frankensaw by mixing up the parts. :)

You need to determine what caused this saw to arrive at the state that it came to you. pressure test on engine can be as simple as some bicycle rubber tube cut out where the valve is fixed to the tube and that snugged down over the exhaust or inlet, and gentle pressure applied, hit block with soapy water and brush , turn the crank, see how the seals and base is.

Dont assume anything, your doing an autopsy on the saw, so each and every part needs close attention, you will find the reason sooner or later, harlyt has posted pics before of the inlet manifold squashed and the impulse hole blocked from the deforming that took place.

Could just be poor fuel mix, poor use and lots of abuse. or something else.


Thanks mate, you are right, I’m a little impatient! I’m in no rush other than to say I was able to fix my first saw. I think my lack of experience is showing in that I want to get it working soon so that I can say to myself it is possible for an inexperienced me to be able to fix these.

After the first I think it will be more relaxed!

You are absolutely right though, slow down...

I’ll hold back modifying the 025 carb as that saw “works” or at least runs for a second and dies... the 180 didn’t even do that before I worked on it.

The current carb, with its idle that won’t adjust seems part of the problem and I can’t seem to get that screw out, any suggestions ?

Thanks to everyone who has chimes in on my first chainsaw strip and rebuild, its awesome and hugely appreciated :)
 
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