A heavy-duty chainsaw requires a large amount of compression whereas as a chainsaw with smaller engine needs less compression to convert fuel into energy. If a chainsaw has a 2 stroke engine, then the maximum compression it requires is 110-130 PSI. Similarly a 4 stroke engine needs 2 times more compression than the 2 stroke engine that is around 180-210 PSI. Now how much compression does the engine of a chainsaw needs depend upon the capacity of its motor and temperature. A cold engine will need the compression of 50-100 PSI whereas a hot engine will require compression above 150 PSI. Too much hot or cold engine does not work or even start to produce vacuum pressure inside engine.
Other things is porting, fuel/air density and a lot more…. Some saws get higher compression for various reasons. Around 200 is pretty normal seen higher and lower in same saws and perform just as good. Around 220-250 is were it starts taking toll on saws parts and our elbows.
2×4. 08-17-2017 23:25:13 Re: Chainsaw has too much compression in reply to EGBinOR, 08-17-2017 20:57:42. 08-17-2017 22:05:54 Re: Chainsaw has too much compression in reply to EGBinOR, 08-17-2017 20:57:42 Check for side play in the crankshaft. Russ from MN. 08-17-2017 21:23:47 Re: Chainsaw has too much compression in reply to EGBinOR, 08-17-2017 20:57:42.
I have a Stihl 032 which I bought in the 70’s. It has and still does run great-if I can start it! At times pulling the starting rope is almost impossible. It always pulls and starts again after running a bit. It’s been a super saw and still is, when I can start it.
why does my chainsaw have too much compression Related Question:
What causes high compression in a chainsaw?
Many problems with compression are related to fuel. Old or bad fuel can cause lots of headaches with yard equipment. Try draining any of the gasoline mixture left in the gas tank and add fresh fuel. If this does not solve the problem, it may be related to excessive fuel caused by problems in the gas lines and filters.
What would cause too much compression?
When a cylinder has high compression, it means there is liquid oil or a high carbon deposit in the combustion chamber, which displaces air. As the combustion chamber is essentially smaller, the air gets compressed more and the pressure rises.
How much compression should a chain saw have?
According to Stihl USA, the minimum compression reading for their chainsaws should be around 110 psi. Some individual engines may run a bit higher or lower and the temperature of the tool can affect readings.
Why is my chainsaw hard to pull and kicks back?
If your chainsaw is hard to pull, here are some common causes: The pully system is snagged or stuck. The starter assembly is stuck or sticky. The housing may be damaged.
What is the purpose of a decompression valve on a chainsaw?
What is a decompression valve? A decompression valve releases some of the compression from the combustion chamber during the starting procedure, making the engine easier to turn over when pulling the recoil rope.
What happens if engine compression is too high?
Engine damage can be caused by compression pressures that are too high and can result in difficult starting and detonation.
Can carbon build up cause high compression?
My research tells me carbon buildup should create high compression. A: Not necessarily. If the carbon buildup is on the piston rings or ring grooves, it can prevent the rings from sealing properly, thus creating low compression.
Does a Stihl 036 have a compression release?
Re: Add comp release to older Stihl? A 036 is a 60cc with quite a high compression and Malamute has a bad shoulder, so he could use a compression release. A friend has the same problem, but a compression release can’t be fitted to his saw.
Does a Stihl chainsaw have a decompression valve?
To make starting the STIHL 4-MIX engine easier, the engine has been fitted with a decompression system which extends the valve opening times when starting. Starting the prize-winning STIHL 4-MIX engines is thus convenient and quick.
What should the compression be on a Husqvarna 55 chainsaw?
Re: Husky 55 Imo 125 psi is fine.
How much compression does a 2 stroke need to run?
It is advisable to read between 110–130 PSI on two-stroke engines. You should still expect a great engine in these environments as compression rates have fallen below 80 or 90.
Will a chainsaw start with low compression?
Checking Compression Levels Pull on the starter rope until the compression reading maxes out. Most chainsaws will operate well with compression readings that range from 100 to 160 psi. After checking the function of the starter assembly, the operator can move on to determining if compression is dropping or increasing.
How long does it take to Unflood a chainsaw?
The first option is the easiest since it doesn’t require any effort on your part, it just takes time. Many people wonder if a flooded chainsaw will fix itself? The answer is yes, but not always. By letting the chainsaw sit for about 20 minutes it will allow some of the fuel inside the engine to evaporate.
How do you fix a flooded chainsaw?
The more hands-on method to start a flooded chainsaw: Have the chain break on. Turn the choke off. Activate the fast idle (by engaging the throttle lock/trigger assembly or pulling the choke out and pushing it back in. Turn the on/off switch to on.
How do compression release valves work?
A compression release mechanism works to ease the starting of internal combustion engines by allowing them to spin up to starting speed without having to work against the pumping action of the pistons.