Irus ER
Built: approx. 1960–1970 · Series: Balkenmäher
More machines from model year 1960
Irus ER (bar mower) – air-cooled single-cylinder two-stroke engine with 7.5 hp at 3,000 rpm, 500 mm cutting width, built from around 1960 to 1970.
The ER is a bar mower with a single-cylinder two-stroke engine, of a type built from around 1960 to 1970. Bar mowers of this kind were mainly used in hill and grassland farming, on ground too steep or too small for larger, wheel-driven mowing machines.
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The air-cooled single-cylinder engine of 246 cm3 displacement runs on a 1:25 petrol-oil mixture and produces 7.5 hp at 3,000 rpm. With a 500 mm working width, 2,000 mm length and 1,200 mm overall height, the ER is a compact, hand-guided machine. Its 20 km/h top speed applies to transport between work areas, not to the mowing itself.
A two-stroke engine running on a petrol-oil mixture was the common design for hand-guided bar mowers of this power class, being light, simple in construction and needing no separate oil circuit. Machines of this kind belong to the group of single-axle motor mowers that still play a role today on steep ground and specialty crops where larger vehicles cannot be used.
When buying an old bar mower, the condition of the cutter bar and the blade guide matters most: worn guide rails and loose blades noticeably reduce cutting quality. The two-stroke engine should be checked for compression and the condition of the piston rings, and the correct 1:25 mixing ratio must be observed on every restart. Drive belt and clutch lever also belong on the checklist; parts are usually only available through dealers specialising in vintage equipment.
Sources: SpecCodex-Register: Kennwerte des Modells Irus ER
Technical data
Engine
| Fuel | 1:25 Benzingemischcorrect |
|---|---|
| Power | 7.5 hpcorrect |
| Power | 7.5 hpcorrect |
| Rated speed | 3,000 rpmcorrect |
| Cylinders | 1correct |
| Displacement | 246 cm³correct |
| Cooling | air-cooledcorrect |
Dimensions and weights
| Length | 2,000 mmcorrect |
|---|---|
| Width | 500 mmcorrect |
| Height | 1,200 mmcorrect |
| Ground clearance | 100 mmcorrect |
Drivetrain and chassis
| Drive | 2-Takt Hirth Motorcorrect |
|---|---|
| Gearbox | 1 Rückwärts und 2 Vorwärtsgängecorrect |
| Top speed | 20 km/hcorrect |
Origin and approval
| Construction | Frontanbaubetriebencorrect |
|---|
Frequently asked questions
How much power does the Irus ER have?
The Irus ER delivers 7.5 hp.
What engine does the Irus ER have?
1 cylinders, 246 cm³ displacement, 1:25 Benzingemisch.
How fast does the Irus ER go?
Top speed is 20 km/h.
What are the dimensions of the Irus ER?
2,000 mm × 500 mm × 1,200 mm.
When was the Irus ER built?
Production years: ca. 1960–1970.
What to check before buying
- Check the hour meter against the service records — a replaced instrument is the most common gap.
- Compare the data plate and chassis number with the papers.
- Shift the gearbox cold and warm — jumps only show up at temperature.
- Load the hydraulics and watch for sag.
- Ask about parts availability for this build year — the running costs hang on it.
A general list for this type of machine — no substitute for an inspection or an appraiser.
We do not sell machines. We ask the dealers who carry this model and come back with price and lead time.
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This page carries 15 individual figures for this model. They come from 1 recorded source; every figure can be traced there. What we cannot document is not here — we leave gaps open rather than estimate them.
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Tractor in 3D section
Turn the model, look inside and click an assembly — each one is explained.