Is This How You Treat Your Chainsaw at Home?

By Raul A. Angulo

Take a good look at the face in photo 1 and memorize that expression. Make sure it leaves an imprint on your mind. This is Stan Wainscott. He is the 22-year veteran and fire service specialist (master repair technician) in the Seattle (WA) Fire Department’s (SFD) Services Division. Every fire department has a Stan Wainscott. These are the guys who fix all the equipment we break. When Wainscott is wearing this face, it’s usually accompanied by one of the following remarks:

• What were you knuckleheads cutting with this saw, battleships?
• The city actually pays you guys for destroying this equipment?
• Do you know how much this costs?
• This is destroyed! It doesn’t need fixing, it needs to be replaced!
• Is this how you treat your power equipment at home?

It’s not good when that face is matched with one of the above remarks. The company officer will have some explaining to do, and it’s usually through a letter to the fire chief. Equipment repair costs are extremely expensive and siphon money away from the budget that could be used to purchase additional specialized equipment, like a new thermal imaging camera with the latest technology.

Stan Wainscott

(1) Stan Wainscott is the 22-year veteran of the Seattle (WA)
Fire Department Services Division who fixes all the stuff we
break. You don’t want Wainscott to look at you like this.
(Photos by author.)


It’s hard to attach a figure to the money that is wasted to repair damaged equipment because of a lack of regular maintenance, poor maintenance, or no maintenance. The core issue could be laziness, lack of pride and ownership, or ignorance. Either way, it boils down to a lack of professionalism.

Core Equipment

The chainsaw is one tool that gets a lot of use by firefighters. It’s the work horse for truck company operations. It’s also one of the tools that needs to be cleaned and fueled after every use, but sometimes that doesn’t get done. There are lots of makes and models out there, so the first thing you need to do is read and follow the owner’s manual, especially the instructions for recommended maintenance. It’s a good guess that firefighters don’t read the owner’s manual on power tools they’re familiar with. Many of us own chainsaws, so we sometimes assume everyone knows how to use one and clean one. Not so. When senior firefighters show the new guy the saws, some might give the “quick start” version and take shortcuts to proper orientation. The result is new firefighters don’t get properly trained because important information was left out. As they train newer firefighters, they pass on only the information they know, which was incomplete to start with. Then when equipment gets damaged, you get the proverbial excuse, “Well no one ever showed me that.”

damaged cylinder heads

(2) Here’s an example of damaged cylinder heads from cutting
tar roofs. When cutting wood, debris flies right through the
cooling fins. However, the chainsaw’s running temperature is
110°F. That is hot enough to melt tar debris right to the fins.


Unlike the circular rescue saws, which use a flat-edged carbide tip blade (not a tearing tooth), the chainsaw carbide tip blades are alternately set at 45 degrees so they make a jagged cut. This ripping saw is the most dangerous tool in the fire service. Without proper training and handling, it can ruin your career in five seconds. During my first year as a firefighter on Ladder 1, we were operating on the roof of a commercial structure fire. I was cutting with the saw and another firefighter tapped me on the shoulder to get my attention over the noise. Instead of turning my head, I turned my whole body with the saw running full throttle. The chain cut through both layers of his turnout pants but missed his skin! Whew! I still get teased about that.

Death for a Saw

Nothing burns up a chainsaw quicker than cutting through tar. Tar roofs on houses, commercial structures, and waterfront piers are brutal on chainsaws. There’s really no chainsaw designed to cut tar; they were made to cut wood. In the old days, firefighters tasked with vertical ventilation on a tar roof had to first scrape off the tar or score the roof down to the wood where they were going to make their cuts. Otherwise, they would gum up the chain and the saw would stall. When carbide tip blades became available on the chains, we were able to cut through anything-even tar. Carbide tip chains made the ventilation evolution faster and the practice of scoring or scraping tar started falling by the wayside. What many firefighters didn’t realize was that it wasn’t the gummed-up chain that was stalling the saw. It was tar melted on the cylinder head that was causing the problem. This remains the number one reason we still burn up chainsaws today.

air-cooled design of this engine

(3) Because of the air-cooled design of this engine, the
cylinder fins need to be clean and free of debris buildup.
These spaces are difficult to reach on the saw and are often
overlooked and ignored. Often only the easily accessed
cooling fins are cleaned, allowing debris to build up on the
rest of the cylinder. This limits the efficiency and life span of
the chainsaw.


The circular rescue saw, which is often used to cut ventilation holes on flat roofs, has a blade guard that throws the cutting debris away from the engine. Notice that sparks are always thrown away from the saw when it’s used to cut a metal door. Not so with a chainsaw. Debris is thrown every which way, especially back at the saw, the sawyer, and anyone else standing behind the saw.

How Tar Does Damage

Wainscott explains, “This engine is air cooled. There is an intake side and an exhaust side. Put you hand next to the cylinder head when it is running full throttle.” Company officers can take the chain off the bar for safety if they want to show this demonstration. The intake side of the engine is like a vacuum. It will suck your hand right up against the pull-rope housing. When you’re cutting wood, debris flows right through the fins without a problem. However, this engine’s running temperature is about 110°F, and that’s hot enough to melt the tar right to the cooling fins of the cylinder head, clogging the air intake. It would be like blocking the radiator of your car and running it for 30 miles full speed and not expecting engine damage despite the steam and the smoke.

“At a fire, if you have to cut through tar and burn up a saw, well that is the cost of doing business,” says Wainscott. “But if you’re cutting tar on acquired structures for training and you burn up a saw, there is no excuse. You’re needlessly damaging expensive department equipment.”


(4) By attaching a five-inch-long 9⁄64-inch bit to a drill motor,
you can knock a lot of the melted tar off the cooling fins. The
drill acts like a high-speed rotation file, cutting a two-hour
scraping job in half. Drill right through the hardened debris
and run the bit along the surface of the fins.


Cleaning the Fins

If you decide to cut through tar roofs and manage to accomplish it without burning up the saw, you need to clean all the cooling fins properly. The maintenance problem is that personnel only clean the fins that are visible. They don’t remove enough of the engine housing to expose the entire cylinder head, so only half of the cylinder gets cleaned. The other 50 percent remains blocked. The saw will still start and operate, but it’s “wounded.” Eventually you lose cylinder compression. It will drop to 140, then 130; it may even finish a ventilation operation at 120. But once the engine compression drops to 110 or less, the saw won’t run. Older saws that aren’t properly maintained could be on their last leg. You may get them started one time and that’s it.

“Tar that’s been baked on the fins is tough to get off,” says Wainscott. “It takes a lot of scraping. The brushes can’t get all the way in there and they’re not strong enough to do the job. A flathead screwdriver works, but it takes a lot of work. Some of these guys don’t even floss their teeth. It’s a two-hour scraping job, and the guys won’t do it. That’s where the drill comes in.”

Using some rubber-flex tubing that snugly fits over the top

(5) Using some rubber-flex tubing that snugly fits over the top
of a spark plug is an easy way to reinsert a new spark plug
into the engine. It allows you the reach and “the feel” to
properly line up the threads and help prevent cross-threading
the plug.


Cleaning Method

After numerous burned-up chainsaws came across Wainscott’s work bench with a “fix” tag, all of which were a result of cutting tar roofs, he had to come up with a faster way of getting the tar off the cooling fins. A five-inch-long 9⁄64-inch drill bit did the trick. On the end of a power drill, the 9⁄64-inch bit was perfect for knocking all the tar gunk off the fins. It was thin and long enough to reach through the entire fluted space between the fins, and it cut the cleaning time in half. In fact, this new procedure was so effective, Wainscott sent a five-inch-long 9⁄64-inch drill bit with instructions to every truck company in the city.

The SFD Services Division uses Oil Eater®-a non-toxic, noncorrosive, and biodegradable cleaner/degreaser that is excellent at breaking down the adhesion of tar products. We also use an automotive grade brakes and parts cleaner.

Dry brush the chain while it is still assembled; it’s easier to clean. Disassemble the saw and remove the chain and the bar. You can soak the chain in the brake and parts cleaner. Wipe down the bar with Oil Eater. Make sure the fuel cap and bar oil cap are on tight so they don’t leak. Use the drill and start knocking baked-on tar. Keep the spark plug in place to protect the cylinder from loose debris. Remember, you’re not drilling into any part of the cylinder head. You’re using the drill like a rotating file, running it through the debris and along the surfaces of the cooling fins.

This is how a cleaned cylinder should look when the job is finished

(6) This is how a cleaned cylinder should look when the job is
finished. The pull-cord side of the saw is also the intake side.
When cutting on a tar roof, the buildup will be greater on the
intake side of the cylinder head.


Once that is fairly clean, tip the saw on its side, pull-cord (intake) side up. Now you can run the brakes and parts cleaner through the cooling fins with a brush to finish cleaning the cylinder head. Positioning the saw with the pull-cord side up protects the coil and electrical components from the cleaning fluid. If you use the Oil Eater, it shouldn’t harm the coil, but you want to protect the coil nonetheless.

The Rest of the Saw

The air filter has a prefilter band around it. Both can be cleaned in warm soapy water and left to air dry. If you keep the prefilter band clean, often the air cleaner is fine and doesn’t need to be soaked.

Change the spark plug as needed. Wainscott found a small section of rubber tubing that snugly fits over the spark plug and helps to thread a new spark plug back into the cylinder without cross-threading.

That’s about it. The rest of the cleaning is common sense. Refuel the saw and top off the bar oil. Wipe down the saw and reassemble it. Run the brush through the groove in the bar. It’s a good idea to flip the bar after each cleaning. Make sure you set the chain in the right direction. The carbide teeth need to be facing forward. Don’t laugh: The saw will run and the chain will spin even if it’s backward. It won’t cut anything, but it will run.

When reassembling the saw, flip the bar

(7) When reassembling the saw, flip the bar. This allows for
even wear and tear on the bar. Make sure you put the chain on
so it spins in the right direction. The carbide tip teeth need to
be facing forward. This is what the saw should look like when
it’s put back together. This is also what Wainscott should look


If you cut clean wood, maintenance is pretty simple, but if you cut through tar, you had better listen to Wainscott on this one. Seattle uses the Stihl MS460 rescue chainsaw. They cost about $1,300 each. A cylinder and piston repair for this saw runs $700 to $800. That’s more than half the cost of a new saw.

Case in Point

Seattle’s Holly Park was a large housing development that was demolished. There were numerous acquired structures available for training. “At Holly Park, eight saws were ruined,” recalls Wainscott. “A few years ago, we burned up 10 saws-all cooked from training on acquired structures with tar roofs. We spent about $8,000 fixing chainsaws that year-all preventable. But the word’s getting out. They’re showing this technique to all the new recruits in drill school, and that’s part of the new curriculum. We’ve had a couple of major training sessions on acquired structures, and I didn’t see any saws come in from those sessions, so I think we’re on the upswing.”

I personally had to face the wrath of Wainscott when I brought in two burned-up chainsaws from Ladder 6. I got a personal lesson on this technique. I also made the decision to train my crews to score the tar down to wood as much as possible if we encounter a tar roof-especially if it’s just for training. I’d been lucky in the past. But, now I understand. Scoring or scraping the tar off a roof may take a little extra time, but if it prevents my saw from burning up, it’s worth it.

RAUL A. ANGULO, a veteran of the Seattle (WA) Fire Department and captain of Ladder Company 6, has more than 30 years in the fire service. He is a member of the Fire Apparatus & Emergency Equipment editorial advisory board. He lectures on fire service leadership, company officer development, and fireground strategy and accountability throughout the United States, Canada, and Mexico.

Stan Wainscott’s Chainsaw Tips

  1. If it SMOKES, then STOP!
  2. Avoid cutting tar if possible.
  3. Ensure the chain is tight before running. When pulled away from the bar, only half a tooth should be exposed.
  4. Ensure the chain brake is on before starting.
  5. Take the slack out of the cord before pull starting.
  6. Use the five-inch 9⁄64-inch drill bit to clean between the cooling fins.
  7. Use Oil Eater or brake and parts cleaner (nonchlorinated) to finish cleaning the cylinder head and cooling fins.
  8. Clean the air prefilter band and air filter with warm soapy water.
  9. Flip the bar each time you clean the saw.
  10. Don’t put the chain on backward. Make sure the carbide teeth are facing forward.

No posts to display