Chainsaw Compression Release

Explanations of the purpose and value of a compression release valve on a chainsaw, and some advice on starting a stubborn saw with less pull-back on the rope. February 22, 2011

I just bought an 075AV and it was delivered without a compression release. It has been removed and the hole plugged. The person I bought it from said most guys like them better without a compression release, because they get a little more power out of them. This may be true, but without one they pull so hard. I'm afraid I will either break the starter rope, or my arm. Could anyone shed some light on this subject for me?

Forum Responses
(Sawing and Drying Forum)
From contributor J:
I don't know about benefit of removing it. It sounds bad to me. In my opinion your fingers are most at risk. If you use it this way you have to be careful to have a very firm grip on the pull, so it doesn't get yanked out of your hand and through your fingers. I have 090AV's and usually do three or four pulls using the compression release then if it doesn't start, another one without, whereupon it usually starts. Before I learned this I hurt my hand one morning about 20 years ago and can still occasionally feel it.

From contributor B:
Yeah, it's kind of like using any other tool without its safety device; can you do it? Do you take that chance? If you have reservations, find one and reinstall it. I have a saw that is a real bear to start and I have to get it set just right under my knee and hold on tight when I give all I have to pull the cord. If it decides to start, it pulls nicely; if not, it will pull the cord handle out of my hand and yeah, it hurts. There is no compression relief available on that old saw, so I treat it with respect and say nice things to it when I need to use it.

From contributor L:
Personally, I will never again own a chainsaw without one. My first saw was an old Craftsman, which didn't have one. It took an act of Jobe to get it started, but I usually managed. The technique was to throw it downward with the left hand, while yanking the rope with the other. One day unbeknownst to me the flywheel key sheared off, leaving the ignition timing in an unknown state. On the first pull, it sucked the starter rope back so hard it tore two ligaments in my forearm, and dislocated my shoulder. Just a word from someone who's been there.

From contributor R:
This depends on the saw and your preference. I have had many saws in the past couple years, two 394's had no compression switch and were bolted up. I am currently running two 395's since the older two died. My two year old 395's compression switch blew about a year ago, so I pulled one of the solid bolts from one of the old 394 parts saws and have been running like that since. I never used the switch anyway, and the saw is easy to pull.

I bought another 395 about a month ago, the compression switch hasn't blown yet, and there is no noticeable power difference. In addition to the Husky saws I have one Stihl MS 880 and I hate it. Not only is it hard to pull and the compression switch a must, but the air filter clogs up in 30 seconds when pulling my 96", 66", and 59" bars.

From the original questioner:
Thank all of you for your input. It has helped me make my decision to box the saw up and return it. I tried to put a release in it but the hole had been brazed shut. The seller I bought it from told me a lot of these older saws have had the compression release hole brazed shut. There is no way I want to crank that monster over without one. Oh well live and learn. If I buy another one I will be sure to ask if the release works.

From contributor R:
In the future I would stick with Husqvarna, they are simply a better built saw. They have better anti vibration, better air filtration, lighter, more power per CCl, and better overall design.

From contributor A:
I have had several saws with compression release but have never used it. Most of my saws are Husky’s and not that hard to start. We have a Stihl and it has a ritual to get it to start but does start by the fourth pull. Maybe it has something to do with how much and often you use it.

From contributor S:
The key to avoiding the engine kicking and pulling the starter rope out of your hands is to always pull the engine over slowly till you get some compression built up. Release the starter rope and then pull a short sharp pull to start the engine. In this way you will get two firing cycles from your pull and end it on the exhaust/power stroke. If the engine has failed to start it will still spin far enough to release the pull start dogs from the fly wheel and should a backfire occur the starter rope will not be pulled from your hands. The other option if your set up includes a saw frame is to always use two hands to pull the started rope.

The only way the compression release could affect power is if it was not working and was staying partly open once the saw fired. I usually do not use them as I find I can start a saw with far fewer pulls without the release being activated. Ensuring your spark plug is in good condition and the air filter is clean goes a long way to ensure easy starting as well.

From contributor D:
I've made the majority of my living with a chainsaw for the last thirty years. I had a tough time learning to start a saw (they didn't have compression releases back then) but once I got the hang of it there was no problem. One of my first saws was an076 super. I found the 051 more prone to snap back. When compression releases first came out, it was standard practice to remove them and plug the hole. They had a habit of sticking open. I don't know of any professional saw operators who use one, but thinking back, it would have been a nice feature when I was learning.

From contributor A:
I had the same problem with a Stihl 038 and found a solution by fixing the saw to a thick, short piece of board using fillets and turnbuttons. This allowed me to stand on the board with both feet and start the saw using both hands. It is now very easy to start and the turnbuttons make for fast removal of the saw from the board. The spikes at the front can be utilized to give a secure fixing at this point.