Starting Up That Chainsaw

Husqvarna 130

If you're like me, you own a small chainsaw but only use it once or twice a year. Every time I need to use it again, I have to re-familiarize myself with the whole ordeal. How do I start this thing again? Where does the oil go? Why isn't it starting right away? And so on.

So here's a quick refresher (for me and for you).

A chainsaw like this has a "2-stroke" engine. You may see this type of engine in weed-wackers and other small but powerful handheld yard tools. It's called 2-stroke because the piston inside the engine does all its work (intake, compression, power, and exhaust) all in a single cycle of the piston. The first stroke is the piston going up (the "upstroke") and the second stroke is the piston being forced down (the "downstroke").

Unique to the 2-stroke engine (as apposed to the 4-stroke engine found in your lawn mower) is that the oil it needs to lubricate the internals of the engine is MIXED DIRECTLY with the fuel itself. In a 4-stroke engine, there is a separate reservoir for oil, but in a 2-stroke you have to mix in the oil directly to the fuel chamber/reservoir.

2-Stroke Fuel Oil

For a Husqvarna 130 (it's pronounced HUSK-VARNA), it takes a 50:1 fuel to oil ratio, meaning that for every 50 units of gasoline you mix it with 1 unit of oil. This is such an essential setup step that the chainsaw came with a supply of oil to mix with the first fuel you put into it. These come in 2.6 oz bottles and are meant to be entirely dumped into 1 gallon of gasoline (use a dedicated "mixed" gas canister and label it so it doesn't get confused with "gasoline only" containers). This oil is labeled "Synthetic Blend 2-Stroke Oil".

That fuel mixture (once prepared) goes into the fuel reservoir of the chainsaw, which is clearly labeled.

There's another (essential) reservoir on the chainsaw: the bar and chain oil reservoir. This too is oil, but it's reservoir supplies the chain itself with lubrication (the fast spinning chain produces an enormous amount of friction and thus heat, so oil is essential). Make sure this reservoir is filled.

Bar and Chain Oil and Location of Reservoir

A third setup step is to make sure the chain itself is fairly sung along the bar. This is a common adjustment (so common that the saw comes with its own adjustment tool). To tighten the tension on the chain, first loosen the two hex nuts a bit, then turn the flathead screw located on the front, just to the side of the hex nuts. It doesn't take much, maybe a quarter of a turn of the screw.

Special Tool to Tighten the Chain Tension along the Bar

Most likely you'll need to sharpen the chain itself, especially if you were cutting into the roots of a tree and let the spinning chain hit the dirt and quickly discovered how fast a chain can be dulled by contact with dirt - just a few seconds (cough cough). We'll tackle that in another blog post, but it's not that difficult to sharpen the blade/chain. You just need a specific rounded file (for chains with a 3/8" pitch, use a 7/32" (5.5mm) round file) and you don't have to remove the chain from the saw or take anything apart. Even if you don't let the chain touch the ground, chainsaw blades get dull INCREDIBLY FAST just under normal use, so this will become part of life with a chainsaw.

3 Points of Contact (Foot, Hand, Ground)

Starting the Chainsaw:

Quick Review of the Chain Brake:

• Chain Brake FORWARD = ENGAGED (chain locked)

• Chain Brake BACK = DISENGAGED (chain can spin and cut)

1. Set the saw on the ground and follow the "3-points of contact" rule. I typically step on the handle itself (flat space below the trigger), and put my left hand pressed firmly down on the saw handle, and the ground itself serves as the third point of contact. This prevents the saw from jumping around once started.

   
   

2. ENGAGE the Chain Brake by PUSHING the brake handle FORWARD, away from the engine. This is the large grayish handle that is located exactly in front of your top hand (left hand). Now the chain is prevented from spinning, regardless of how high the engine is revved up while running (when you start a chainsaw, the engine may temporarily rev up high, and you don't want that chain to start spinning until you're ready to use the saw to cut.)

   
   

3. Flip the red switch to the UP position (Up = Choke/Start, Middle = Run, Down = Stop). This engages/closes the choke, restricting any airflow into the engine chamber, creating the "fuel rich" mixture needed to start the saw from a cold start.

   
   

4. Press the primer bulb 3-6 times, injecting oil/fuel mixture directly into the carburetor's intake (the carburetor combines fuel with air under normal operation). This "primes" the engine, meaning it doesn't have to draw fuel up from the tank on the first pulls, making it start much easier.

   
   

5. Pull the starter cord with a sharp, smooth motion. You may have to do this 1 to 3 times until the engine "pops" or "fires" for a brief second and then dies. The engine is stalling because the choke is closed, preventing air from being drawn in.

   
   

6. Flip the red switch to the middle position (RUN). This opens the choke.

   
   

7. Pull the starter cord 1-2 more times, and the engine should start. Let the engine run for 15-30 seconds to warm up. The chain won't spin because the Chain Brake is still engaged (in the forward position). The throttle triggers should not have to be pressed AT ALL during this warmup period, the engine will just idle by itself. This is a common point of confusion: when starting the chainsaw, you prime the engine, apply the chain brake forward, start the engine, and let it idle for 15-30 seconds before doing ANYTHING with the triggers.

   
   

8. When you're ready to cut, DISENGAGE the chain brake by PULLING it BACK toward the engine and your hand. To make the chain spin you need to rev up the engine a bit (though now, you may see it spin slowly just from the chain idling and the brake disengaged). The top trigger is called the Lockout Trigger. It's a safety trigger that must be pressed in for the actual Throttle Trigger (the trigger below the handle) to do anything. The Throttle Trigger is what revs the engine. With the chain brake disengaged (back) you should now see the blade come to life. You're ready to cut!

That Chain Brake is a wonderfully designed piece of safety. While you're using the saw, the brake handle is back toward your hand (brake disengaged, blade spinning freely). If the saw happens to buck on you - and this is a VERY common occurrence - the entire saw will forcefully be kicked upward and back toward your face. This motion will cause that Chain Brake handle to bump into your top (left) hand and push the handle forward, engaging the brake! IF that mechanism fails, today's saws have an additional inertia sensing mechanism that will cause that brake handle to jump forward anyway, engaging the brake automatically.

Whew! There's a lot to a chain saw, and it takes some practice to really learn how to start it, let it idle and how the chain brake and throttle levers work. But if there's any safety advice that's more important than all others it is this: don't ever become complacent when using a chainsaw. Always hold it firmly and expect it to jump and bite.

Happy chainsawing!!