What the f..........is going on here?

[Normzilla]

Metering lever height set properly?

Bingo. My first thought. Had an old Husky 65 did this to me. Fuel everywhere.

 

[Stump Shot]

While it could be any number of things mentioned here, it is very hard to diagnose something without having it in your hands. This is a very interesting problem, and am still curious to see what it is. Most times these will just kill the engine, but a super rich condition when warm that still allowed the engine to run is a new one on me.

 

[mgr1]

After all buying aftermarket carbs, carb kits, time involved and a lot of headaches is oem better and less stressfull.

Just my toughts so dont shoot me.

 

[Wonkydonkey]

After reading all this, somewhere I thought, if it were me. I would pull the Oem carb off the Stihl 660 and put it on the clone. Tune it. And see how it stands up..

If all was well, then it must be the China carb, it give a starting point. You could even fit the China carb the the Stihl 660.

Then it would be a process of elimination, ie sticky metering lever, wrong diapham (tit too big), pop off, etc.

And on another note, I’m just sayin,,,, not that it maybe your problem. I had a China carb, that when the saw was tilted forwards it died, I'm pretty sure it was all down to the butterfly valve not havin a cut out, so when I was setting it up, it was not right from the start, till I filed the butterfly valve and set up again it ran good.
So you have to check everything.

I'm subscribed to this, as it’s very interesting,

Cheers

 

[Basher]

Bingo. My first thought. Had an old Husky 65 did this to me. Fuel everywhere.

Norm, with the metering lever set too high could you get it to start and idle? Usually the ones I find set that way won`t idle at all but if started with the throttle near wide open they could clear themselves to run WOT until one let off the throttle and they would flood out.

 

[PogoInTheWoods]

After all buying aftermarket carbs, carb kits, time involved and a lot of headaches is oem better and less stressfull.

Yes!

Wasn't too keen to do that as I don't want to mess with the oem carb and ruin something. BUT, I may do that when the used carbs get here. Cheers.

Forgive me for making a simple point, but..., if you're not willing (or confident enough) to pull the pump diaphragm and the metering components from a known good carb for testing in one of your problem carbs (and possibly narrow down or identify the problem that way), but still keep messing with all this other stuff like aftermarket carb kits and used carbs..., well, I gotta wonder about your actual determination factor with all this in the first place. 'Bout the only thing you could ruin by installing the components of your OEM carb into one of the flakey carbs might be be your ego from wasting so much time pissing up a rope for the last 4 pages if indeed that simple troubleshooting method happens to solve your problem. Could also conclusively prove the carbs in question are simply AM junk and that you should cut your losses and move on after having hopefully learned a valuable lesson or two about AM carbs.

While a problem like this is frustrating, it's also frustrating watching someone else just spin their wheels in the process of trying to solve it. Sometimes the desired solution isn't achievable or even reasonable to expect. Gotta know when to really dig in, or just turn the page. However you proceed, good luck with it.

 

[Wonkydonkey]

Just saying, pogointhewoods

but can you just peel off a diaphragm of a good working carb, and put it on another carb then put it back to the original carb and will it still work like you an't pissed with it or tore it up.

Simple question, but unless I’ve put a bit of grease on the carb to help seal it, they don’t seem to like being torn apart without messing sum ting up.

 

[PogoInTheWoods]

.....but can you just peel off a diaphragm of a good working carb, and put it on another carb then put it back to the original carb and will it still work like you an't pissed with it or tore it up.

Sure. I've pulled carbs apart for simple cleaning many times and re-used the existing gaskets and diaphragms if they were still in decent condition. Never had a problem with things not sealing normally on re-assembly. If the gaskets separate/stick/tear, or the diaphragms are stiff or warped, they'd obviously need replaced anyway. I personally wouldn't apply a sealant when re-using decent carb gaskets/diaphragms. If it's needed, the parts should be replaced or perhaps the mating surfaces may require attention. A quick carb pressure test would certainly identify any issues there.

 

[Normzilla]

Norm, with the metering lever set too high could you get it to start and idle? Usually the ones I find set that way won`t idle at all but if started with the throttle near wide open they could clear themselves to run WOT until one let off the throttle and they would flood out.

Yes started but like starting a flooded saw. Idle can't remember if it did. But once I set metering lever fixed it. Thanks to Help from Aaron

 

[Basher]

Poge,...one can learn a lot from working on flaky components, I do it as often as this stuff comes my way, it becomes an exercise or experiment to prove to myself I can fix this. Consulting with others with experience in the same field also expands ones knowledge base..

 

[PogoInTheWoods]

Agree completely. However, one also needs to implement the suggestions and methods of others in order to broaden their knowledge base from the actual experience gained.

Only trying to stimulate the initiative factor a little more, that's all. LOL

Sorry if I came off as a dick. I'm certainly guilty of that on occasion.

 

[traffic903]

Ok, so I'm going to respond as a general statement addressing a few different people, just so it is all kept in one post, because clearly some of my responses have gone undetected.

1. I have a working carb on the saw now.
2. I have 2 OEM used carbs on the way.
3. A new genuine carb here in Aus is almost $300.
4. It is a kit saw. I have a Cross top end on it, muffler mod, timing advance and popup piston. It makes around 180psi and goes good.
5. I have many other saws, so I'm not desperate to be back cutting with this. It is a toy.
6. I'm retired. I have plenty of time on my hands. Plenty!
7. I'm interested in what this problem is, not about getting the saw running, because it already is with another carb.
8. The metering lever is set correctly. The carb works perfectly right up to the point it floods at 13 grand.
9. I am using aftermarket parts because it is an aftermarket carb. Furthermore, I don't know whether some of you guys in the states understand just how bad we get f@#$ed over price wise here by Stihl. And to top all that off, my dealer (the only one for 100km) carries no parts stock at all. Well other than filters and chains and such. Everything is a 2 week wait minimum.
10. I have run it with the OEM carb from my MS660. It runs perfectly then.
11. I don't have an "ego" problem and that whole comment was unnecessary.
12. Clearly some of you guys fix saws for a living. This causes you (correctly) to look at things from a perspective of time is money. That is not my perspective. To me, time is........time. It gives me something to do for a day or so when I encounter a problem. I almost look forward to them in a way. A challenge. Yes I used the word frustrating to describe this problem, but it has a different meaning for me than maybe you, because for me time does not equal money.
13. After reading @Basher 's post regarding the nozzle check valve I reinstalled the dodgy carb and recreated the problem. As the saw hits around 13000 fuel just pours out the nozzle. So much so that it then drips (large droplets) after the throttle is closed and subsequently causes the saw to flood and die if I don't feather the throttle. It appears to me he is onto it. So I will look here first, then if that doesn't change anything, move on to the next area. I don't mind how long it takes, I'm learning about how the different components effect things.

I hope this addresses some of the concerns raised.

 

[Basher]

Ok, so I'm going to respond as a general statement addressing a few different people, just so it is all kept in one post, because clearly some of my responses have gone undetected.

1. I have a working carb on the saw now.
2. I have 2 OEM used carbs on the way.
3. A new genuine carb here in Aus is almost $300.
4. It is a kit saw. I have a Cross top end on it, muffler mod, timing advance and popup piston. It makes around 180psi and goes good.
5. I have many other saws, so I'm not desperate to be back cutting with this. It is a toy.
6. I'm retired. I have plenty of time on my hands. Plenty!
7. I'm interested in what this problem is, not about getting the saw running, because it already is with another carb.
8. The metering lever is set correctly. The carb works perfectly right up to the point it floods at 13 grand.
9. I am using aftermarket parts because it is an aftermarket carb. Furthermore, I don't know whether some of you guys in the states understand just how bad we get f@#$ed over price wise here by Stihl. And to top all that off, my dealer (the only one for 100km) carries no parts stock at all. Well other than filters and chains and such. Everything is a 2 week wait minimum.
10. I have run it with the OEM carb from my MS660. It runs perfectly then.
11. I don't have an "ego" problem and that whole comment was unnecessary.
12. Clearly some of you guys fix saws for a living. This causes you (correctly) to look at things from a perspective of time is money. That is not my perspective. To me, time is........time. It gives me something to do for a day or so when I encounter a problem. I almost look forward to them in a way. A challenge. Yes I used the word frustrating to describe this problem, but it has a different meaning for me than maybe you, because for me time does not equal money.
13. After reading @Basher 's post regarding the nozzle check valve I reinstalled the dodgy carb and recreated the problem. As the saw hits around 13000 fuel just pours out the nozzle. So much so that it then drips (large droplets) after the throttle is closed and subsequently causes the saw to flood and die if I don't feather the throttle. It appears to me he is onto it. So I will look here first, then if that doesn't change anything, move on to the next area. I don't mind how long it takes, I'm learning about how the different components effect things.

I hope this addresses some of the concerns raised.

I actually had to re read the whole thread before I caught/seen and realized your problem would start just above 13,000 rpm , that is when the saw starts to flood so I believe its the check valve opening prematurely, likely a defective unit opening too soon. I like solving mysteries like these, keep with it and solve it.

 

[paragonbuilder]

Ok, so I'm going to respond as a general statement addressing a few different people, just so it is all kept in one post, because clearly some of my responses have gone undetected.

1. I have a working carb on the saw now.
2. I have 2 OEM used carbs on the way.
3. A new genuine carb here in Aus is almost $300.
4. It is a kit saw. I have a Cross top end on it, muffler mod, timing advance and popup piston. It makes around 180psi and goes good.
5. I have many other saws, so I'm not desperate to be back cutting with this. It is a toy.
6. I'm retired. I have plenty of time on my hands. Plenty!
7. I'm interested in what this problem is, not about getting the saw running, because it already is with another carb.
8. The metering lever is set correctly. The carb works perfectly right up to the point it floods at 13 grand.
9. I am using aftermarket parts because it is an aftermarket carb. Furthermore, I don't know whether some of you guys in the states understand just how bad we get f@#$ed over price wise here by Stihl. And to top all that off, my dealer (the only one for 100km) carries no parts stock at all. Well other than filters and chains and such. Everything is a 2 week wait minimum.
10. I have run it with the OEM carb from my MS660. It runs perfectly then.
11. I don't have an "ego" problem and that whole comment was unnecessary.
12. Clearly some of you guys fix saws for a living. This causes you (correctly) to look at things from a perspective of time is money. That is not my perspective. To me, time is........time. It gives me something to do for a day or so when I encounter a problem. I almost look forward to them in a way. A challenge. Yes I used the word frustrating to describe this problem, but it has a different meaning for me than maybe you, because for me time does not equal money.
13. After reading @Basher 's post regarding the nozzle check valve I reinstalled the dodgy carb and recreated the problem. As the saw hits around 13000 fuel just pours out the nozzle. So much so that it then drips (large droplets) after the throttle is closed and subsequently causes the saw to flood and die if I don't feather the throttle. It appears to me he is onto it. So I will look here first, then if that doesn't change anything, move on to the next area. I don't mind how long it takes, I'm learning about how the different components effect things.

I hope this addresses some of the concerns raised.

I love the way you think! I’m tuned into your findings...

 

[traffic903]

I actually had to re read the whole thread before I caught/seen and realized your problem would start just above 13,000 rpm , that is when the saw starts to flood so I believe its the check valve opening prematurely, likely a defective unit opening too soon. I like solving mysteries like these, keep with it and solve it.

Yes thank you very much for your help with this.

 

[traffic903]

I love the way you think! I’m tuned into your findings...

Cheers mate. I feel very confident the cause is now identified.

 

[traffic903]

I just want to apologize to @Adirondackstihl for not crediting him with the suggestion of the nozzle check valve first. Having had time to read back through everything now (particularly to see where I could have come off as egotistical or similar), I see that he mentioned it pretty much straight up. So, I am sorry for that mate and I thank you (and Basher) for the suggestion. I haven't had time to further this any more today but will follow up once I have dealt with it.

 

[Wonkydonkey]

I guess I better go look up a check valve, I can’t think what it is atm.


Ahh, main fuel nozzle
This site gave me the info
http://outdoorpowerinfo.com/repairs/zama_c1u_m29a_carb.asp
Cheers

 

[traffic903]

I guess I better go look up a check valve, I can’t think what it is atm.


Ahh, main fuel nozzle
This site gave me the info
http://outdoorpowerinfo.com/repairs/zama_c1u_m29a_carb.asp
Cheers

Yeah I think that's why I didn't catch it when first suggested. Only had the simplest understanding of that prior to now.

 

[Basher]

Some of the terminology may play a part in the confusion, different names/terms used for the same part, ie. check valve, check nozzle, governor valve have all been used to describe the same part, maybe has to do with what is commonly used in a local area. Problems like this discussed out in the open helps many members that have less experience gain some more even if it becomes boring for those that already have been there and done that.