Seems that high volume carbs use the posilock metering diaphram to needle fulcrum arm to insure absolute movement of the needle as the diaphram moves. It could be that the arm to diaphram lock also stops the needle from moving to deep as the lock will contact and stop an over stroke of the diaphram.
I have a NEW 261C doing this.. I really havent used it I purchased it new a couple of years ago.. I start it for a few minutes every 2 months or so.. I only have put stihl premix fuel in it but I wonder if the dealership just threw some crap fuel mix in it when I purchased it? It bogs under a load at high rpm but otherwise runs good..
Its hard for me to follow the history of the saw here. You say you haven't used it but only use stihl premix. Is the original tank of fuel from the dealer still in there or was it used up? Did it ever run decent?
@@TheGreasyShopRag I know its confusing lol.. the dealership put fuel and bar oil in it I believe thats a requirement to sell stihl but I may be wrong.. I purchased it new 2 years ago. I cranked it at least every other months and let it run say 5 minutes.. I only needed the saw 2 days ago I thought it would probably be better to dump put fresh fuel so I dumped what was in it out and filled it with stihl premix.. This saw could have had this issue from the day I purchased it because it has never been put under a load until a couple days ago.. Either it came new this way or Maybe AgPro put poor quality fuel I thought after seeing your video.. I was searching for Stihl bogging on top end..
@@rksg2003 Yes it may have been like this the whole time but even if they used the highest quality gasoline available 2 years is a long time for fuel to go sour. Just because you were able to start it doesn't mean the fuel wasn't still getting old. I think you may have to open up the carb and take a look.
@@TheGreasyShopRag I appreciate you following up with me. Is there anywhere stihl brand carb kits can be purchased? If not. An you point me to a good brand and thanks again.
@@rksg2003 Stihl owns Zama so if you have a Zama carb you may only be able to buy those parts from a Stihl dealer. This isn't true for all model carbs. I have had mixed results using off brand kits so I recommend using genuine Zama or Walbro kits. These are ordered using the model numbers found on the carb itself.
If you mean at the 2:30 mark then no I don't feel any other testing was required. It would have only led me to the same conclusion. If you mean at the end then yes more adjusting was done outside and in a log. My employer isn't paying me to make videos but does allow me to hang a camera over the bench so that is where all the videos end. Thanks for watching!
I assumed it would make removing the linkage easier. Right or wrong it sure doesn't hurt to take a look under there for debris, especially given the condition of this saw.
If you know what you're looking at you don't always need a gauge. You'll also noticed I used the old lever. This is an older video and I have been trying to do a better job of explaining and teaching rather than just showing what I did. Thanks for your comment.
I live on the west coast of British Columbia so my 038 magnum and 066 are both full wraps. I used to heli log for 13 years and of course,all our big saws were full wrap 😊
I'm the guy pulling the cord. I'm not weak but I'm not super strong so you're probably right about the compression. Its funny how many things I notice watching these repairs that I didn't notice during the repair. I am curious about the sound, it doesn't seem off to me.
I’ve got an ms290 I received as a trade for shells. He said it’s always ran hot and then becomes hard to start up after it gets hot. I saw the piston and cylinder were scored up so I I installed a new cylinder head and piston along with a new impulse, I installed a new diaphragm, new needle (I adjusted the needle so it sits level), new small circle screen, new fuel pump screen thing whatever that thin piece is called. New fuel line, fuel filter, air filter and spark plug yet it did not fix anything. It has bad trigger response, sounds like a slight bog at first but has normal top end. It bogs under load. I’m lost, I have no idea what’s wrong with it. Any ideas?
Spraying carb cleaner in an assembled carb on a saw won't help. You can spray carb cleaner inside a disassembled carb to remove gunk as seen at 5:00 . Don't ever spray carb cleaner into a running saw as carb cleaner doesn't contain the lubricating oil that your saws bearings need.
Possibilities include a hole in the tank, a hole in the main fuel line, a jacked up tank vent, a loose pump cover on the carb and of course that wonderful flip fuel cap.
Nice catch. And that's why you need someone who specializes in this stuff, otherwise a guy could just load up the parts cannon and still not find it. Laterrr.
I know what the problem is. You need to have the muffler ported and the head planed (install a high compression gasket) and run VP C-12 racing fuel with Amsoil Dominator at 40:1. …your welcome. 🍻
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Nicely done. Huge difference before and after
You're right. I know some may not be able to tell but if you know what you're listening for then it was a big difference.
Great Video Production. Excellent Information, Instructions, and Demonstration.
Thanks for watching!
Good diagnosis. Nice to know that water will cause this issue. 👍
Beautiful display of talent
Awesome Troubleshooting! I'm with you do it right the first time! Appreciate the knowledge and videos they are awesome
Thanks for taking the time to watch!
Seems that high volume carbs use the posilock metering diaphram to needle fulcrum arm to insure absolute movement of the needle as the diaphram moves. It could be that the arm to diaphram lock also stops the needle from moving to deep as the lock will contact and stop an over stroke of the diaphram.
I have a NEW 261C doing this.. I really havent used it I purchased it new a couple of years ago.. I start it for a few minutes every 2 months or so.. I only have put stihl premix fuel in it but I wonder if the dealership just threw some crap fuel mix in it when I purchased it? It bogs under a load at high rpm but otherwise runs good..
Its hard for me to follow the history of the saw here. You say you haven't used it but only use stihl premix. Is the original tank of fuel from the dealer still in there or was it used up? Did it ever run decent?
@@TheGreasyShopRag I know its confusing lol.. the dealership put fuel and bar oil in it I believe thats a requirement to sell stihl but I may be wrong.. I purchased it new 2 years ago. I cranked it at least every other months and let it run say 5 minutes.. I only needed the saw 2 days ago I thought it would probably be better to dump put fresh fuel so I dumped what was in it out and filled it with stihl premix.. This saw could have had this issue from the day I purchased it because it has never been put under a load until a couple days ago.. Either it came new this way or Maybe AgPro put poor quality fuel I thought after seeing your video.. I was searching for Stihl bogging on top end..
@@rksg2003 Yes it may have been like this the whole time but even if they used the highest quality gasoline available 2 years is a long time for fuel to go sour. Just because you were able to start it doesn't mean the fuel wasn't still getting old. I think you may have to open up the carb and take a look.
@@TheGreasyShopRag I appreciate you following up with me. Is there anywhere stihl brand carb kits can be purchased? If not. An you point me to a good brand and thanks again.
@@rksg2003 Stihl owns Zama so if you have a Zama carb you may only be able to buy those parts from a Stihl dealer. This isn't true for all model carbs. I have had mixed results using off brand kits so I recommend using genuine Zama or Walbro kits. These are ordered using the model numbers found on the carb itself.
Here to find out what’s up with my 660. Thank you 🙏🏽
Thanks for watching!
Should you have tested under load? Set the idle and high rpm?
If you mean at the 2:30 mark then no I don't feel any other testing was required. It would have only led me to the same conclusion. If you mean at the end then yes more adjusting was done outside and in a log. My employer isn't paying me to make videos but does allow me to hang a camera over the bench so that is where all the videos end. Thanks for watching!
Curious why you removed the handle assembly. I remove the carb without touching it.
I assumed it would make removing the linkage easier. Right or wrong it sure doesn't hurt to take a look under there for debris, especially given the condition of this saw.
Should you have set the needle arm height?
If you know what you're looking at you don't always need a gauge. You'll also noticed I used the old lever. This is an older video and I have been trying to do a better job of explaining and teaching rather than just showing what I did. Thanks for your comment.
Super video, nice work.
Thanks for watching!
It’s weird to not see a full wrap handle on a big saw. 😊
round here its weird to see a full wrap handle.
I live on the west coast of British Columbia so my 038 magnum and 066 are both full wraps. I used to heli log for 13 years and of course,all our big saws were full wrap 😊
To me @ 1:40 when 1st pulling over it sure seems low on compression. Or dude is super strong. The sound is off to tho.
I'm the guy pulling the cord. I'm not weak but I'm not super strong so you're probably right about the compression. Its funny how many things I notice watching these repairs that I didn't notice during the repair. I am curious about the sound, it doesn't seem off to me.
I’ve got an ms290 I received as a trade for shells. He said it’s always ran hot and then becomes hard to start up after it gets hot. I saw the piston and cylinder were scored up so I I installed a new cylinder head and piston along with a new impulse, I installed a new diaphragm, new needle (I adjusted the needle so it sits level), new small circle screen, new fuel pump screen thing whatever that thin piece is called. New fuel line, fuel filter, air filter and spark plug yet it did not fix anything. It has bad trigger response, sounds like a slight bog at first but has normal top end. It bogs under load. I’m lost, I have no idea what’s wrong with it. Any ideas?
It should be pressure/vac tested for leaks before you run it anymore.
Good diagnosis. Good to know water will cause this condition.
Mine is doing the exact same thing.
Can i spray some carb cleaner in there?
Spraying carb cleaner in an assembled carb on a saw won't help. You can spray carb cleaner inside a disassembled carb to remove gunk as seen at 5:00 . Don't ever spray carb cleaner into a running saw as carb cleaner doesn't contain the lubricating oil that your saws bearings need.
Hey mate hows it going. Im having a hard time getting my 066 to behave.
Do u have the correct fuel needle height measurement
That measurement is based on the model of carb you have. I doubt they all used the same carb over the years but maybe. No, sorry, I can't help you.
what a great vid, thanks alot!
Thanks for watching!
Cho tôi xin cách chỉnh bộ chế hòa khí stihl 660 chuẩn nhe
Thats not a procedure that can be easily explained in the comments section. You'll have to find a video showing the process. Thanks for watching!
Where did you get that fuel line tool?
I knocked the flux off a welding rod, bent it to shape and covered it with fuel hose 🙂
Super video.
Thanks, and thanks for watching!
Wat make a 066 sthil leak gas after u put it up it had been 3 days before it started leaking it runs fine
Possibilities include a hole in the tank, a hole in the main fuel line, a jacked up tank vent, a loose pump cover on the carb and of course that wonderful flip fuel cap.
Nice catch. And that's why you need someone who specializes in this stuff, otherwise a guy could just load up the parts cannon and still not find it. Laterrr.
I suspect the first part would have been a carb. It would have run but what a waste of money.
I know what the problem is. You need to have the muffler ported and the head planed (install a high compression gasket) and run VP C-12 racing fuel with Amsoil Dominator at 40:1.
…your welcome. 🍻
That would do it!
It worked on mine 👍🏻