Stihl MS361 - Need help choosing a good carb

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2-StrokeDude

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Joined
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Hey guys, I am sure some of you have seen the MS 361 I rebuilt and have posted about on here, and I have a question for those of you who have more knowledge than me... :omg:😆

Parts on the saw:

- Meteor Piston with caber rings
- Meteor Cylinder
- Tecomec Crankshaft
- Proline Genuine Parts crank bearings (not made in china)
- RTS Crank seals
- Aftermarket stock muffler
- Stihl air filter
- Aftermarket fuel lines and filter
- Bosch spark plug
- Aftermarket carb - (this is what I'm concerned about)

The question I have is regarding the aftermarket carb I bought off of HL Supply when I bought some other parts, and I thought It would be ok to use since I have had decent success using AM carbs on some equipment I've fixed up to sell. However I think I got a bad one.

No matter how much tuning, tips and tricks I do I cannot keep it from shutting off after low throttle inputs. It runs pretty good otherwise. This saw has got me pretty annoyed at this point but I am almost positive it is a carb issue.

So I did what may others said on this forum and I took the carb apart to inspect it and make sure it is in good shape (even though it is new). Everything looked good. Needle was set correctly, and passages were clear. I even put it in my ultrasonic cleaner for 45 min just to make sure. Reassembled, put it back on the saw, and set to factory specs of 1 turn on L and H screw. Had to adjust the L and H screw to get it to idle and run fine but then when trying to make sure it didn't shut off at low throttle it still died out. Great.....

I thought, "either the carb is bad or there is an air leak somewhere".

So I bought the OEM Stihl exhaust block off rubber plate, and the OEM Stihl carb block off manifold. Tested for Vac/Pressure leaks. Nothing. No leaks. I also tested the carb for pressure leaks and it had none.

So that rules out everything I can think of as far as possible reasons it is shutting down. So I figure the china carb is bad.

Now I'm back to the drawing board, and need to buy a new carb. But because I don't use chainsaws that much I really, REALLY don't want to drop $100 on a Walbro carb. (I would rebuild the original but the L screw is snapped off and I have tried everything to get it out but cannot.)

I found a Zama carb on ebay that has a ZAMA logo and a Stihl logo cast into it. Says it works on the Stihl MS 361, and looks OEM. My question is, should this be a good carb to use on my saw? Looks like the OEM one I had, except it is not a Walbro carb which is what the saw had on it originally. It is from a name brand that Stihl now owns and I have worked on Zama carbs on other machines and they seem good. I'm not sure if Stihl used Walbro carbs on some years of the 361 and then switched to Zama carbs on another year, but it looks like (and I think) it will fit. Should I trust this carb? And, do you think it is ok to use on my saw, even though it had a Walbro on it from the factory?

https://www.ebay.com/itm/1557957756...lJ56qtVnrosQqChBAIM9Zq3wSR4O2FCwDzDtWfkTVXytA
Also, just to prove to you guys that the vacuum / pressure test is good, I’m attaching videos of me doing it…
View attachment IMG_1026.mov
 
Hey guys, I am sure some of you have seen the MS 361 I rebuilt and have posted about on here, and I have a question for those of you who have more knowledge than me... :omg:😆

Parts on the saw:

- Meteor Piston with caber rings
- Meteor Cylinder
- Tecomec Crankshaft
- Proline Genuine Parts crank bearings (not made in china)
- RTS Crank seals
- Aftermarket stock muffler
- Stihl air filter
- Aftermarket fuel lines and filter
- Bosch spark plug
- Aftermarket carb - (this is what I'm concerned about)

The question I have is regarding the aftermarket carb I bought off of HL Supply when I bought some other parts, and I thought It would be ok to use since I have had decent success using AM carbs on some equipment I've fixed up to sell. However I think I got a bad one.

No matter how much tuning, tips and tricks I do I cannot keep it from shutting off after low throttle inputs. It runs pretty good otherwise. This saw has got me pretty annoyed at this point but I am almost positive it is a carb issue.

So I did what may others said on this forum and I took the carb apart to inspect it and make sure it is in good shape (even though it is new). Everything looked good. Needle was set correctly, and passages were clear. I even put it in my ultrasonic cleaner for 45 min just to make sure. Reassembled, put it back on the saw, and set to factory specs of 1 turn on L and H screw. Had to adjust the L and H screw to get it to idle and run fine but then when trying to make sure it didn't shut off at low throttle it still died out. Great.....

I thought, "either the carb is bad or there is an air leak somewhere".

So I bought the OEM Stihl exhaust block off rubber plate, and the OEM Stihl carb block off manifold. Tested for Vac/Pressure leaks. Nothing. No leaks. I also tested the carb for pressure leaks and it had none.

So that rules out everything I can think of as far as possible reasons it is shutting down. So I figure the china carb is bad.

Now I'm back to the drawing board, and need to buy a new carb. But because I don't use chainsaws that much I really, REALLY don't want to drop $100 on a Walbro carb. (I would rebuild the original but the L screw is snapped off and I have tried everything to get it out but cannot.)

I found a Zama carb on ebay that has a ZAMA logo and a Stihl logo cast into it. Says it works on the Stihl MS 361, and looks OEM. My question is, should this be a good carb to use on my saw? Looks like the OEM one I had, except it is not a Walbro carb which is what the saw had on it originally. It is from a name brand that Stihl now owns and I have worked on Zama carbs on other machines and they seem good. I'm not sure if Stihl used Walbro carbs on some years of the 361 and then switched to Zama carbs on another year, but it looks like (and I think) it will fit. Should I trust this carb? And, do you think it is ok to use on my saw, even though it had a Walbro on it from the factory?

https://www.ebay.com/itm/1557957756...lJ56qtVnrosQqChBAIM9Zq3wSR4O2FCwDzDtWfkTVXytA
Also, just to prove to you guys that the vacuum / pressure test is good, I’m attaching videos of me doing it…
Pressure test video :
View attachment IMG_1025.mov
 
It's not uncommon for manufacturers to use different carb brands over the years, so the switch to Zama should be fine. Just ensure the compatibility details match your saw model
 
Hey guys, I am sure some of you have seen the MS 361 I rebuilt and have posted about on here, and I have a question for those of you who have more knowledge than me... :omg:😆

Parts on the saw:

- Meteor Piston with caber rings
- Meteor Cylinder
- Tecomec Crankshaft
- Proline Genuine Parts crank bearings (not made in china)
- RTS Crank seals
- Aftermarket stock muffler
- Stihl air filter
- Aftermarket fuel lines and filter
- Bosch spark plug
- Aftermarket carb - (this is what I'm concerned about)

The question I have is regarding the aftermarket carb I bought off of HL Supply when I bought some other parts, and I thought It would be ok to use since I have had decent success using AM carbs on some equipment I've fixed up to sell. However I think I got a bad one.

No matter how much tuning, tips and tricks I do I cannot keep it from shutting off after low throttle inputs. It runs pretty good otherwise. This saw has got me pretty annoyed at this point but I am almost positive it is a carb issue.

So I did what may others said on this forum and I took the carb apart to inspect it and make sure it is in good shape (even though it is new). Everything looked good. Needle was set correctly, and passages were clear. I even put it in my ultrasonic cleaner for 45 min just to make sure. Reassembled, put it back on the saw, and set to factory specs of 1 turn on L and H screw. Had to adjust the L and H screw to get it to idle and run fine but then when trying to make sure it didn't shut off at low throttle it still died out. Great.....

I thought, "either the carb is bad or there is an air leak somewhere".

So I bought the OEM Stihl exhaust block off rubber plate, and the OEM Stihl carb block off manifold. Tested for Vac/Pressure leaks. Nothing. No leaks. I also tested the carb for pressure leaks and it had none.

So that rules out everything I can think of as far as possible reasons it is shutting down. So I figure the china carb is bad.

Now I'm back to the drawing board, and need to buy a new carb. But because I don't use chainsaws that much I really, REALLY don't want to drop $100 on a Walbro carb. (I would rebuild the original but the L screw is snapped off and I have tried everything to get it out but cannot.)

I found a Zama carb on ebay that has a ZAMA logo and a Stihl logo cast into it. Says it works on the Stihl MS 361, and looks OEM. My question is, should this be a good carb to use on my saw? Looks like the OEM one I had, except it is not a Walbro carb which is what the saw had on it originally. It is from a name brand that Stihl now owns and I have worked on Zama carbs on other machines and they seem good. I'm not sure if Stihl used Walbro carbs on some years of the 361 and then switched to Zama carbs on another year, but it looks like (and I think) it will fit. Should I trust this carb? And, do you think it is ok to use on my saw, even though it had a Walbro on it from the factory?

https://www.ebay.com/itm/1557957756...lJ56qtVnrosQqChBAIM9Zq3wSR4O2FCwDzDtWfkTVXytA
Also, just to prove to you guys that the vacuum / pressure test is good, I’m attaching videos of me doing it…
View attachment 1142827
I'd just save yourself sometime and trouble and go ahead and buy what was originally on it. Then you are guaranteed a fix. With no issues as long g as it's tuned right. I have a real problem with all these Chinese parts on professional Saws. When you look to buy used you gotta inspect everything with a magnifying glass to make you are not buying a Chinese Stihl!
 
OP said, "... No matter how much tuning, tips and tricks I do I cannot keep it from shutting off after low throttle inputs. It runs pretty good otherwise. This saw has got me pretty annoyed at this point but I am almost positive it is a carb issue...."
--------------------------
I thought the same with mine. I took the carb off, cleaned the strainer, which was partially clogged, and it ran perfectly after that.
1710190639535.png
Part #26. A 24-hour soak of the carb in a jar of mixed fuel can also do wonders. It's worth a try,
 
OP said, "... No matter how much tuning, tips and tricks I do I cannot keep it from shutting off after low throttle inputs. It runs pretty good otherwise. This saw has got me pretty annoyed at this point but I am almost positive it is a carb issue...."
--------------------------
I thought the same with mine. I took the carb off, cleaned the strainer, which was partially clogged, and it ran perfectly after that.
View attachment 1161218
Part #26. A 24-hour soak of the carb in a jar of mixed fuel can also do wonders. It's worth a try,
Also check your metering valve. Also acetone is the best thing to soak your carb in after you take it apart throw everything in a jar besides gaskets of course. Let it sir overnight and clean it out next day. Any varnish from ethanol brushes right off.
 
Just remember pump gas will wreck the diaphragm in a year or so.

My saws are spoiled princesses in general, but this one is destined for a particularly cushy life. It'll be my truck saw, riding around in a nice duffel bag on the back floorboard of the truck or in the trunk of the car when I think I might need a saw. Lots of miles, hopefully not much use.

It might get E0 at some point, but will almost certainly spend it's life on canned premix.
 
I must be living right as the Brand X carbs I've used have functioned without issue.
Stihl and Husqvarna don't make their own carburetors and what shows up on them today are made in China.
The high tech company I worked for moved some of their manufacturing to China, as despite the specs you provided, they often used parts that were from lower cost manufactures. If this happens to a $20,000 product, I don't want to think what occurs with carburetors.
 
I took a bad AM carb a customer had me change it out for an OEM one. The Am one had metallic crud blocking two of the feed drillings/passages that no amount of US vibratory cleaning could dislodge.Carbs were clean as possible so for just curiosity sake I got out the jet drill case and tried chasing the passages, it took a fair bit of time turning the pin vise but once the jet drill made its way to the venturi and after blowing with comp air and carb cleaner through the passages that carb has worked fine on a neighbors saw for the last two seasons. It seems the Am manufacturers take a few shortcuts in their cleanup process.
 
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