This cross-flow scavenged, 2-ringed engine was introduced in the early 70's with production continuing into the early 80's. Early engines incorporated an exhaust baffle coupled to the throttle arm of the carburetor which helped retain heat for a better idle. This feature disappeared in 1974 since the use of mufflers had become more common and made the exhaust baffle redundant. External appearance remained pretty much unchanged over the years although internal improvements included an enlarged lower end, bushed con rod and head design changes. In the last few years the engine was also equipped with the MKX series carburetor. Distinctive features included an eagle emblem cast into the rear cover and American flag on the side of the crankcase. A good engine requiring no modifications, except perhaps updating the carb. on earlier versions.

Eagle II .60

Bore: .907
Stroke: .937
Disp: .604
Wt: 17oz.
HP: 1.9 at 15,000 RPM

Introduced in the late 70's, the Eagle II was a radical departure from the first Eagle .60. Incorporating an usual 3-piece crankcase design, this new Eagle also featured a single high tension ring, schneurle porting, a removable head button and massive internal construction for durability. High compression often resulted in operating and reliability problems, so modifications are sometimes necessary.
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Eagle II Racing

Bore: .907
Stroke: .937
Disp: .604
Wt: 17oz.

The Eagle II was also available in a rear intake, rear exhaust "racing" version. Unique concepts included a one piece rotor disc and shaft to maintain squareness with the mating surface. The large diameter case permitted a larger than average rotor disc and larger than average intake. Note: very few of these were ever produced.

Eagle III .60

Bore: .907
Stroke: .937
Disp: .604
Wt: 17oz.

The Eagle III version was introduced in 1980 with a slightly modified crankcase and numerous internal changes including: a re-designed piston, shorter con rod, improved porting, new head button, heavier duty rear bearing and improved taper lock and thrust washer. The old 2-jet carburetor was also replaced with the newer two-needle MKX series. Still, compression problems remained and sometimes modifications are required to achieve reliable operation, particularly with nitro content over 5%.
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Eagle III .60 Rear Exhaust

Bore: .907
Stroke: .937
Disp: .604
Wt: 17oz.

While the cylinder casting of the standard Eagle can also be rotated for rear exhaust applications, the true Rear Exhaust model was also ported for tuned pipe operation. Fox claimed 16,000RPM on and 11x7 prop.

Eagle IV .60 & .74

60 Size	74 Size
Bore: .907 Stroke: .937 Disp: .604 Wt: 19oz.	Bore: 1.00 Stroke: .937 Disp: .736 Wt: 19oz.

Significant costs involved in machining the split crankcase used on the Eagle II and III, necessitated a change to maintain an acceptable profit margin. Thus, the Eagle IV was born and remains the current version.

The IV features a conventional, single piece crankcase, however the separate cylinder is retained. Also new was the introduction of a .74 version. Both the .60 and .74 were once offered in ringed and ABC versions. The .60 still is, but the .74 is now only available with a ring. Over compression still tends to be a problem, particularly in earlier models. There have been at least five head button variations in an attempt to tame handling! Modifications may still be required for reliable operation.
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Early Eagle IV's were supplied with the MKX series carb., while current engines use the EZ series carburetor. There have been some problems with the EZ series carburetor, particularly on the larger Fox engines. Modifications may be necessary to correct an overly lean midrange.
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