dooglus
08.06.2021 2:11:19
Any ideas? Something in the ignition I could check? Plug wire resistance? When it's going at full song, it runs great. [links]
See full version: Fouling plugs and clogging muffler screen
Any ideas? Something in the ignition I could check? Plug wire resistance? When it's going at full song, it runs great. [links]
When I first inherited it, I set the carb up where I thought it should be (from the manual, starting from 1.25 turns out low/high - tinkered with it very slightly from there). It is very easy to tell when it is time to fill up on fuel- RPMs will jump up especially if making felling cuts. It sounds erally sweet like that, but I normally immediately shut er down and fill er up. So I wonder if it's not running all the way at the top and is just simply on the rich side when running at WFO. Normal? Or should I take it to the Stihl shop and have them Tach it. [links]
I run a Stihl 028 AV Super, and it is using a lot of plugs and clogging up the muffler screen quite easily. I go through a plug only after maybe 20 hrs (or at least, it will be much easier to cold start with a new plug). Same with the muffler screen. Last I checked, there was no scoring on the piston although I haven't checked compression.
I use Stihl oil at 50:1 and normally use 89 octane gas. The air filter is on the old side but I keep it clean and it is not chewed up. It will also not idle very long after it gets hot, without switching off. The chain still jumps a little bit, at idle. It smokes a good bit. If I engage the brake and set it down for a while after it's been run hard, it'll sign off and I'll have to start it again. more
I love the saw and to be honest there is significant sentimental value to me in it, so I'm considering just retiring it to a glass case in my house, and buying a different workhorse saw. That being said, it is a tool and I want to treat it as such (work hard, play hard, take care of business, take care of the machine) more
Generally speaking, driving the T- screw in on a carburetor means the engine will get a leaner air- fuel mix which allows for higher rpm. Turning the screw counter- clockwise will pull it outwards which delivers a richer air- fuel mix to the engine, resulting in lower rpm. You want to find a sweet spot, not too low nor too rich. Adjust the low and idle screws first before you start tinkering with the high rpm settings. And make sure that the air filter is clean, and that the spark plugs are functioning properly before you tune the carburetor.
✓ If your chainsaw won’t start, not even an idle, then read : Why Won’t My Chainsaw Start? [links]
Finally, you definitely want to check the adjustment screws on the carburetor since these screws control little needle valves which determine how rich/ lean the air fuel mixture is at various rpm levels (idle, low, and high). Every modern chainsaw should come with at least 2 adjustment screws, one for low and the other for high rpms. It is recommended that you never tamper with the high adjustment screw because it is very easy to blow your chainsaw engine if you set it too aggressively. Which is why, manufacturers often install limiter caps on the screws which prevent you from screwing up the carburetor and engine tune beyond repair. [links]
There are many reasons why a chainsaw won’t idle properly, and in this article we’re going to present a step-by-step process which will help you find the issue and rectify it before it causes any additional damage.
Chainsaws are powered by single cylinder 2-stroke engines which rely on an air-fuel mixture in order to generate power. The air- fuel mixture is created in the carburetor, which sucks in atmospheric air through an air filter and mixes it in a very specific ratio with fuel that it pulls from the gas tank of the chainsaw. The gas tank isn’t just an airtight container for fuel, it also packs a little fuel filter which separates all the sawdust and impurities from fuel before it is allowed to enter the fuel line and reach the carburetor.
Once the air-fuel mixture reaches inside the cylinder of the engine after passing through an intake boot (a rubber hose connecting the intake of the engine with the output of the carburetor), it is ignited by an electric spark. This spark happens when high voltage is generated between the insulated inner electrode of the spark plug, and the outer grounded terminal. Air fuel mixture is in aerosol form, and its properties change when subjected to the high electric potential difference of several thousand volts between the two electrodes.
Regardless of the condition of the plug after 100 hours of service, Stihl recommends replacing it with a fresh one. Use a resistor-type plug, and check the manual for your Stihl chainsaw model for recommended replacement plugs. If the plug needs replacing because it is badly eroded, it may be because you're using gasoline with ethanol additive. Ethanol burns hotter than gasoline and can cause the engine to overheat, and one symptom of this is worn plug electrodes. Stihl recommends 89 octane gasoline without ethanol, and in no case should the gasoline contain more than 10 percent ethanol.
If the plug is coated with light brown deposits, and the gap is correct, you don't need to do anything to the plug -- just put it back, and the chainsaw should continue to run normally. If it's coated with black deposits or oil, you should remove them with an emery board or a small piece of 120-grit wet/dry sandpaper. Adjust the gap, if necessary, with pliers. One condition that indicates the need for replacement is wearing of the electrode. If the engine is stalling, and you suspect the plug, test it with a spark plug tester, and replace it if the spark isn't regular and strong. [links]
Part of regular maintenance of your Stihl chainsaw is to remove the plug and inspect it after every 10 to 15 service hours. If the engine is running normally, the outside electrode will probably be covered with light brown deposits. You should also check the gap between the electrodes with a gapping gauge; it should be 0.02 inches. If the engine isn't running normally, the problem is usually evident in the condition of the plug. Thick black deposits indicate that the fuel/air mixture is too rich -- in other words, there isn't enough air in the mixture. A wide gap or corroded electrodes, on the other hand, are indications of a lean mixture. Oil on the plug indicates an oil leak. [links]
The spark plug is an essential part of any internal combustion engine, providing the energy necessary to ignite the fuel. If it's corroded, fouled, worn or otherwise damaged, the engine either won't start or, if it does start, will operate poorly. A poorly functioning engine in a Stihl chainsaw can mean more work for the operator and can even be dangerous. Consequently, Stihl recommends replacing the spark plug after every 100 service hours.
The spark plug in a Stihl chainsaw engine -- or in any engine -- is a simple device. Each time the engine flywheel completes a revolution, a magnet attached to it induces an electric current in a static magnet, and that current generates a spark across the plug's electrodes. The spark ignites the fuel/air mixture in the combustion chamber, and the explosion drives the piston and makes the engine work. If the plug's electrodes are too far apart or are covered with oil, carbon deposits or moisture, the spark is intermittent or weak, which causes incomplete combustion and poor engine performance.
Chris Deziel has a bachelor's degree in physics and a master's degree in humanities. Besides having an abiding interest in popular science, Deziel has been active in the building and home design trades since 1975. As a landscape builder, he helped establish two gardening companies.
Your chainsaw engine can miss the fire or run haphazardly. Or sometimes, the incorrect gap can cause unwanted firing and delay combustion.
How Often Do I Need To Change The Spark Plug In My Stihl Chainsaw?
After ensuring the spark plug is active otherwise let’s now check out the gap. There are few tools available in the market known as “spark plug checker” that will help you to determine the gap. more