The Strunk Busy Beaver is another neat little snapshot of mid-1950s chainsaw design. The saw is heavy, geared, and built to be a practical one-man saw.
In this article, we’re looking at the Busy Beaver’s specs, surviving details, and vintage-era features to see what made this 1956 Strunk model stand out.
Specifications
| Spec | Details |
|---|---|
| Model | Strunk Busy Beaver |
| Manufacturer | Strunk Manufacturing Co., Coatesville, Pennsylvania, U.S.A. |
| Year introduced | 1956 |
| Engine | 1-cylinder |
| Cylinder/intake | Aluminum cylinder with cast iron sleeve; reed valve intake |
| Power | 4 hp / 2.98 kW |
| Weight | 28 lb / 12.7 kg with 16 in / 40 cm bar and chain |
| Clutch/drive | Centrifugal clutch with gear reduction drive, 3:1 ratio |
| Construction/finish | Sand cast aluminum with red enamel finish |
| Ignition/starter | Wico FW2288 or FW2385 magneto; Fairbanks Morse automatic rewind starter |
| Carburetor/air filter | Tillotson HP-12A diaphragm carburetor; Skinner ribbon element air filter |
| Oiling system | Positive gravity feed |
| Maximum engine speed | 4,500 rpm |
| Ignition settings | Timing 0.250 in / 6.35 mm before TDC; breaker points 0.020 in / 0.51 mm |
| Spark plug/gap | Champion J8J, Autolite A7X, or AC M45; 0.030 in / 0.76 mm gap |
| Main bearings | Ball |
| Fuel tank capacity | 2 U.S. quarts / 64 fl oz / 1.89 L |
| Fuel mix | 1/2 pint oil to 1 gallon gasoline, or 16:1 |
| Recommended fuel/oil | Regular gasoline; SAE 30 motor oil |
| Chain spec | 1/2 in pitch, .058 gauge; Strunk Type B chain |
| Guide bar lengths | 16–24 in / 40–61 cm |
The Busy Beaver looks a lot like the earlier Eager Beaver, but it was really the tougher follow-up. On paper, the Busy Beaver steps up to 4 hp instead of 2.5 hp, uses a Tillotson HP-12A/H12A diaphragm carb instead of the Eager Beaver’s MD-60A float carb, runs a higher listed max rpm, and was sold with a wider bar range.
STRUNK BUSY BEAVER
- Instant starting
- Trouble-free operation
- Cuts in all positions
- Durable and powerful
- One finger trigger control (for engine and clutch)
4 HP, 28 LBS.
Reviews
Pictures


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Also, check out these fantastic old STRUNK Chainsaw advertisements from the 1950s and 60s!
