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stihl man 460
Guest
I have a stihl ms440 469 hybrid ported I roasted two pistons on it and one on my ported stihl ms 460 my cousin aka my mechanic says it looks like it's running on straight gas but its not my one put scratches on crank case
Help Support Arborist Forum:
Air leak , poor fuel or too lean on the carb settings. What oil and how much yo mixing?
2 stroke failure
Possible causes:
too low an octane fuel used or fuel with too much alcohol used
jetting too lean or failure of the fuel system, i.e., clogged fuel line or filter, fuel tank not venting, problem with fuel pump, carburetor, air leak into crankcase
spark plug heat range too hot
ignition timing too far advanced, possible failure of the c.d. amplifier box
restricted exhaust system: back pressure too high
overheated, loosely-installed spark plug
redoakman
ArboristSite Operative
Have you tuned the carb since u got it back . 32-1 fuel mix? . score marks on intake and exhaust ?sounds like poor fuel .
You killed two pistons in one saw, and another in a different saw? The first place that I look when something like this happens to one guy is fuel, since it is common between both saws. The other thing common between both saws (it sounds like) is the tuner. Do you have them tuned too lean?
In order to help on this we need a very detailed description and photos of what exactly happened.
- Need to know who ported the saws and what was done to them
- Need to know how you are mixing the fuel, what oil, how much, where the gas comes from
- Need to know your level of tuning knowledge and how you have tuned the saws after their modifications.
- Need to know what you mean "scratches on the crank case"
- Need to know if the builder properly installed the modifications and if vacuum/pressure check was run.
- NEED photos.
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stihl man 460
Guest
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stihl man 460
Guest
Never touched carb sence it got ported by master mind and other one I bought it of fin460 and never touched carbs fuel mixed 32-1 stihl oil score marks both sides scratches in crank case like something was in it these are the only two says that are doing this other are fine my two saws the hybrid is ported by master mind and 460 is wicked work saws
fearofpavement
Trying them all
Does the piston look clean on the other side or is it like that all the way around?
What are you high screws set at?
redoakman
ArboristSite Operative
He said both sides so I take it yes
fearofpavement
Trying them all
1. Not enough oil in gas
2. Lugging (forcing) saw (dull chain, etc)
3. Out of tune
4. All of the above
2. Lugging (forcing) saw (dull chain, etc)
3. Out of tune
4. All of the above
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stihl man 460
Guest
One thing just rang a bell I may have a little bit of a dirt problem I seem to always hit dirt and my chain like most the time dall
Well, a dull chain will do that to a saw if it forced to continue.
redoakman
ArboristSite Operative
Ding ding ding .
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stihl man 460
Guest
My last chain I cut down some old pine low to grownd and that chains f u c k e d
fearofpavement
Trying them all
I tell my southern saw customers that the chips landing on their feet should look like oatmeal. If they look more like cornmeal, they need to stop cutting and sharpen.
fearofpavement
Trying them all
Dulling a chain won't hurt a saw. Continuing to try to cut with a dull chain WILL harm a saw. It can hurt the chain and bar, the clutch and sprocket area and lead to engine damage if continued.
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stihl man 460
Guest
Thanks guy hopefully I don't roast another
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stihl man 460
Guest
But just in case what should top screw be turned at
