Owner’s manual
How many horsepower is a 42cc chainsaw?
For the Craftsman CMXGSAMCX4218 gas chainsaw, the operator’s manual lists engine displacement (42 cc) but does not specify horsepower. Horsepower varies by engine design and RPM, so two 42cc 2-cycle chainsaws can have different HP ratings even with the same cc.
What we can confirm for CMXGSAMCX4218
The CMXGSAMCX4218 operator’s manual provides these model-specific specs you can rely on:
- Engine type: air-cooled, 2-cycle
- Displacement: 42 cc (2.56 cu. in.)
- Fuel/oil ratio: 40:1
- Guide bar length (S180 / CMXGSAMCX4218): 18 in.
- Chain pitch and gauge: 3/8 in. pitch, 0.050 in. gauge
Why 42cc does not equal a fixed horsepower number
“CC” is engine size (displacement), not power output. Horsepower depends on factors such as:
- Porting and cylinder design
- Carburetor tuning and exhaust design
- Maximum governed RPM under load
- Emissions tuning and ignition timing
- Condition of the air filter, spark plug, and fuel mix
Quick reference: cc vs. what it tells you
| Spec | What it means | What it does not guarantee |
|---|---|---|
| 42 cc | Engine displacement (size) | Horsepower rating |
| 2-cycle | Engine type | Cutting speed by itself |
| 18 in. bar | Typical bar length for this model | That you can cut 18 in. diameter wood |
Why it matters
Using the correct model-specific specs helps you choose the right saw chain, guide bar, and fuel mix for CMXGSAMCX4218. That prevents hard starting, poor cutting performance, and premature wear on the clutch, sprocket, bar, and chain.
Last updated: January 2026
What are the most common issues with CMXGSAMCX4218?
The most common issues we see with the Craftsman CMXGSAMCX4218 gas chainsaw are hard starting or no-start, chain not oiling, chain not moving (clutch related), and pull-cord problems. These symptoms usually trace to fuel/air delivery, ignition, bar-and-chain setup, or the recoil starter.
Common problems and what to check first
- Hard start or won’t start: stale fuel mix, clogged air filter, fouled spark plug, or ignition issue.
- Chain won’t move: chain brake engaged, chain too tight, or a worn clutch/clutch drum.
- Chain not oiling: empty oil tank, plugged oiler port, or a failing oil pump.
- Pull cord won’t retract or is stuck: recoil starter spring or pulley damage.
- Cuts poorly or smokes: dull chain, wrong chain tension, or bar oiling problem.
For model-specific operating and maintenance steps (starting procedure, chain tensioning, oiling checks), follow the CMXGSAMCX4218 owner’s manual.
Parts that commonly solve these symptoms
If basic checks do not fix the issue, these are common replacement parts for this model:
- Mtd chainsaw recoil starter assembly 753-10287 for pull-cord and recoil problems
- Craftsman oil pump yd3 753-10297 for no bar-and-chain oiling
- Mtd chainsaw chain, 18-in 713-05042 if the chain is stretched, damaged, or won’t hold tension
- Craftsman chainsaw bar, 18-in 795-00543 if the bar rails are worn or the nose sprocket binds
- Craftsman chainsaw ignition module 753-10291 if there is no spark after plug and switch checks
Quick symptom-to-cause guide
| Symptom | Most likely area | First action |
|---|---|---|
| Won’t start | Fuel/air/ignition | Refresh fuel mix; clean filter; check spark |
| Chain won’t move | Brake/clutch/drive | Verify brake off; set tension; inspect clutch |
| No oil on chain | Oiler/oil pump | Fill oil; clean oiler holes; inspect pump |
| Rope won’t retract | Recoil starter | Inspect starter housing; replace recoil assembly |
Why it matters
Running a gas chainsaw with poor chain tension or no bar oil quickly damages the bar, chain, and clutch; fixing the root cause early prevents bigger repairs and improves cutting performance.
Last updated: March 2026
What is the fuel mixture for a Craftsman 18 chainsaw?
For the Craftsman CMXGSAMCX4218 gas chainsaw (18-inch bar), the correct fuel mixture is 40:1 (gasoline to 2-cycle oil). That equals 3.2 fl oz of 2-cycle oil per 1 U.S. gallon of unleaded gasoline; we recommend following the mixing steps in the CMXGSAMCX4218 operator’s manual.
Correct 40:1 mix amounts
Use this table to measure accurately before you fill the fuel tank.
| Gasoline amount | 2-cycle oil needed (40:1) |
|---|---|
| 1 U.S. gallon | 3.2 fl oz |
| 1 liter | 25 ml |
How we recommend mixing fuel (best practice)
Mix fuel in a separate, approved fuel can (not in the chainsaw tank), then shake to blend.
- Use fresh, clean unleaded gasoline (fuel less than about 30 days old stores best)
- Use 2-cycle oil designed for air-cooled engines
- Measure oil first, then add gasoline to the can
- Cap the can and agitate/shake to fully mix
- Fill the saw outdoors, wipe spills, and move the saw away from the fueling area before starting
Fuel tips that prevent hard starting and engine damage
These points matter on the CMXGSAMCX4218 because a 2-cycle engine depends on the oil in the fuel for lubrication.
- Do not use E85; avoid fuel with more than 10% ethanol
- Do not use old, separated, or stale mix
- Do not “eyeball” the ratio; too little oil can score the cylinder, too much oil can foul the spark plug
- Store mixed fuel in a sealed container and remix (shake) before each use
Why it matters
A correct 40:1 mix helps the CMXGSAMCX4218 start easier, idle more smoothly, and reduces spark plug fouling and premature wear of internal engine parts.
Last updated: January 2026
