Stihl chainsaw runs like crap

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bighead

bighead

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You said white smoke? When I see that I look for air leaks. What have you done to clean the carb?

Get some carb cleaner and spray around looking for leaks.

Any drag on the chain? Can you spin the chain by hand?
 
anderkart

anderkart

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Blue, some of the older Stihl mufflers could be fully disassembled for cleaning. My tree trimming/Arborist company had several chainsaw mufflers that the spark arrestor screen inside had become completely plugged up. The spark arrestor screen is usually the very last component inside the muffler right before the output hole(s).

If your muffler isnt made to take apart you can usually just use a drill through the output holes to drill right through this thin metal screen and defeat the arestor. (then simply tell your customer he needs a new muffler if he doesn't want the possibility of starting fires while using his saw)

I found debris stuck underneath reeds keeping them from closing/making a good seal too...

Then If yours still wont run correctly go pick up a carb diaphragm kit. Its very common for those to develop tiny holes/cracks that you cant see no mater how closely you look. Also spray carb cleaner through every single port/orifice and replace all the fuel lines, especially the pickup/return inside the tank. Also clean or replace the fuel pickup strainer/filter inside the tank. When the fuel lines get old/hard they sometimes dont make a good seal at the fittings, so they suck air and not enough fuel...

Also keep in mind that some of these saws are factory jetted so dam lean they need the (clean/dried and lightly-oiled) air filter fully installed to run correctly. So dont go chasing your tail fighting this issue.

Its usually best to adjust your high speed jet first, then the low, but not always. I usually start somewhere around 1-turn out from lightly seated to get it started, and then fine tune from there.
 
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number 37

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good advice above from Anderkart and others.

PLEASE: wear safety equipment when handling a saw. Not trying to be a safety nazi, but chainsaws are very dangerous esp. one that's working intermittently that may grab/cut/slack off etc...

a really good site to search thru is ArboristSite.com for help

If you have a compression tester, you need to check for compression, and do a leak down test. There can be lots of places for air to leak in and compression to leak out...

It's down to basics: air/fuel/spark. You say it's got plenty of spark, appears to have plenty of fuel (is it fresh?), so that leaves air
Air:
intake: (seems to be clean/working), may need a kit as stated above, but runs up under no load "ok". Are you running it with an airfilter? is it clean/new etc?
exhaust: you say it may be plugged, you can also heat and use plyers to uncrimp folded mufflers to clean it out.
compression: you need to test for compression and leakdown

I'd doubt the timing was changed unless someone tried porting the saw prior to you working on it. "Most" saws are just used by home owners and neglected in maintenance.

Don't run it long without the muffler, or without the chain on it you may add damage to the saw.

and FWIW: $10 isn't enough to take the time to make the vid and ask the questions you've already asked online. A regular saw shop would charge him $50/hr min, +parts, so IMHO your time should be worth $25+ at a min, but that IS a way cool siren you got in trade, so it's a wash ;)
 
Bluethunder3320

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Cool, ill check out that site, great suggestions!!!

Ill check for leaks and check the screen. I dont have a compression tester.

Also, this guy took 70 bucks off the tractor for me, so the 10 bucks is really juste doing a favor... (plus siren)

If your wondering, the siren badge says "stirling fire alarm co, inc. Rochester, NY."

Good lesson: DONT hold the spark plug right overthe sPark plugnhole to check spark. Usually it blows out gas.... Lol oops.
 
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sexyvicta

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check the fuel filter

check the airfliter

check the tank breather

insert new spark plug

check all the rubber lines going into/out of carb

check exhaust port cleanliness if you want

if you done all that and it still bogs then richen up the Low speed circuit a tad and you should be right:D you could prob skip all steps and just do that.

if all those steps fail then i reckon you may needa replace a diaphram in carb
 
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sexyvicta

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oh lols i watched vid.

hes got the chain bar lock thing on?

-thats what my saw sounds like if you lock the bar. Safety first
 
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sexyvicta

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Russ2251 said:
I figured this stuff out with ZERO help.
Can you not do the same?
Click to expand...

no/maybe if i had the saw sitting on my desk here.

Hes asking on forum because he cant work it out for himself. Why would you say 'i've worked it out!' and then keep the solution secret? you may aswel of said nothing. It makes no sense to me boss:D
 
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