So i wanna learn how to tune a chainsaw and thats because my grandpa has a old chainsaw,its a chiness one but he has taken care of it and has had it for 6 years know but it runs poorly so it needs some work and some of that work includes a carb adjustment.But i dont really wanna wreck my 300 dollars husqvarna 120 for that so ive been thinking is buying a chiness chainsaw and learning carb adjustment on that one would be a good idea,plus i wont really cry if my 80 dollars chiness chainsaws breaks down.
Tuning a chainaw
- Thread starter Andrew15
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Tomos770
ArboristSite Guru
Or his videos.....or TRS videos (the repair specialist)...or DonyBoy73 videos...
Those are my 3 "specialists" for getting knowledge about O*P*E equipement!
Those are my 3 "specialists" for getting knowledge about O*P*E equipement!
Tomos770
ArboristSite Guru
Additonally....
StevesSmallEngineSaloon and The Greasy Shop Rag
StevesSmallEngineSaloon and The Greasy Shop Rag
There are some really great guys out there producing some fantastic content. I enjoy all the channels you’ve mentioned above!
Back in the day before anybody even heard of Stihl or Husqvarna it was simply explained as running "rough" no load and "cleaning" up under load. If a saw ran smooth no load it was too lean.
Seems amusing that we ran old Homelites and McCullochs with that very simple formula like forever.
It is actually as clear as a bell if you listen for it.
Seems amusing that we ran old Homelites and McCullochs with that very simple formula like forever.
It is actually as clear as a bell if you listen for it.
When I set up the low end jet, I just make sure that the idle speed is right, ( the chain doesn't "walk"), then I adjust the jet so that the saw neither starts to run faster, or slower. AFAIK, there's a delay between an adjustment, and seeing the result of the adjustment. The air fuel mixture in the crankcase needs a bit to stabilize. If it starts to pick up R.P.M., and then dies... too lean.. If it starts to slowly slow down, .. too rich. Properly adjusted, it should just sit there and idle, for at least a minute.
I like to set mine a bit on the "fat" (rich) side.. That is, that they will idle, no problem, for 15 to 30 seconds before starting to " load up" , or slow down. I find it gives them better low end torque out of the hole. And, they're more willing to idle on a cold start.
I've found that the hard part to wrap your head around, is that the main jet affects the low jet. Best description I ever read about it basically said that it's like your backyard hose. The tap on the wall ( high jet), controls, ( in addition to the high flow mixture), the total water ( fuel) available, and the low jet has to deal with the fuel sent by the high jet. Every time you **** with the high jet, you also need to re set the low..
I like to set mine a bit on the "fat" (rich) side.. That is, that they will idle, no problem, for 15 to 30 seconds before starting to " load up" , or slow down. I find it gives them better low end torque out of the hole. And, they're more willing to idle on a cold start.
I've found that the hard part to wrap your head around, is that the main jet affects the low jet. Best description I ever read about it basically said that it's like your backyard hose. The tap on the wall ( high jet), controls, ( in addition to the high flow mixture), the total water ( fuel) available, and the low jet has to deal with the fuel sent by the high jet. Every time you **** with the high jet, you also need to re set the low..
KostasVolos
ArboristSite Operative
Both the High (main) and Low jet (idle) circuits feed their fuel from the metering chamber ( sharing the same "tap on the wall",which actually is the metering needle ) .
From the same metering chamber feed also the acceleration pump if present or the acceleration jet ,which are also separate circuits.
When the saw idles ,the check valve keeps the main jet closed .
Thus the main jet adjustment can not be affecting the idle jet operation .
When at WOT ,Mainly the high
jet ,but also the low jet
(as also any other acceleration jet present or the acceleration pump ) provide the fuel .
Can't really see in which way the high jet adjustment ( which affects the engine operation at WOT ) has anything to do with the low jet adjustment ( which affects engine operation at idle state ,while the main jet is closed shut ) .
For me, it depended on the saw. Some idled different after setting the main jet, some didn't. Or, could be the result of crud in the carb. What else would cause the low end to change when the high end is adjusted?
It totally depends on the carb as to if the high speed jet affects the low speed jet. The key being if it’s a dependant or independent.
That also determines if you should adjust the L first or H first.
That also determines if you should adjust the L first or H first.
And how would one determine this?
Probably just a longer delay going from high back to low due to the volume of fuel being employed at full throttle and left residual in the system.
dony can be long-winded. Its more self-promotion...
Interesting, I haven’t noticed that about Donny. I have been improving my content trying my to take out all the unnecessary wasted time which people seem to be enjoying.
