Explain proper way to adust chainsaw carb


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Old 08-31-21, 09:45 AM
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Explain proper way to adust chainsaw carb

I have a McCulloch M130. Needed a tune up. I watched some videos. I couldn't get it straight if I should adjust lo or hi first or if it even matters. They said to turn each screw in until maximum rpm at idle or wide open respectively and then tun them out till rpms just start to drop. They said if you leave the screws at maximum rpm then your running to lean and you will freeze your engine up. Wellll, I go it running good and took it out to cut. After a while (5 minutes) it started stalling on me and then stopped for the last time. Engine appears seized.
Did it finally just die of old age or did I kill it? I have messed with it before but never had it do this.
I have to get my weed wacker running better but now I am afraid it touch it.
Can anyone clarify the proper proceedure?
 
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Old 08-31-21, 10:47 PM
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really hard to say what happened, on newer saws many do use a tach on them cause you really can only get so close by ear, using the same method would make sure the saw is fully warmed up and when you set the high screw and are starting to richen it up listen for the rpm to drop and keep going till the engine starts missing or 4 stroking due to excessive fuel then you should be close theory is it will sound that way under no load, but will sound normal under a heavy load as it will be able to burn the fuel.
the low side is a little less important but if you get a hesitation when you hit the throttle often adjusting the low slide a little richer will help but you may have to adjust your throttle stop screw also as your adjusting the low side you really dont want your idle to high as you will be getting out of the low circuit and it atleast has to be set high enough the engine does not stall but slightly richer from the highest idle rpm is usually close.
 
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Old 09-01-21, 04:40 AM
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If the engine is seized it sounds like that is it for the saw. It could be repaired but you probably would spend more time and money than the saw is worth.
 
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Old 09-01-21, 08:10 AM
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Not to hijack the thread, trying to wrap my brain around this. Can running too lean literally seize the engine?
 
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Old 09-01-21, 09:10 AM
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Too lean = Not enough lubrication, so yes it's possible.
 
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Old 09-01-21, 12:19 PM
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Yes, running too lean is what seizes the majority of two strokes. Including boat motors and cycles. 2 stroke engines don't have oil, it's mixed in the fuel. If it's not getting enough fuel it not only isn't getting lubricated, it's also running faster and hotter than it should. The combination is death for the engine.
 
 

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