Buyer guide
EY20 Engine Replacement Guide: Dimensions, Output and Compatibility
An EY20 has failed or is being discontinued on equipment that is otherwise sound, and a replacement is needed. The risk is ordering an engine that has the right power and the wrong shaft, which turns a repair into a re-engineering job.
The short answer
- The EY20 designation refers to a petrol engine of about 183 cc, with a 67 × 52 mm bore and stroke in the variant most commonly sold.
- Power class is roughly 2.2 to 2.6 kW continuous depending on rated speed — well below the smallest engine in our range, so an upgrade in output is easy and the fit is the hard part.
- Five measurements decide whether any replacement works: shaft diameter, shaft length, keyway, bolt-hole spacing and shaft centreline height.
- Ask for the drawing before the quotation. A dimensions-only comparison is faster than a trial fitting and costs nothing.
The measurements to take before ordering a replacement
Read from the catalogue row for each model. Scroll the table sideways on a phone.
| Measurement | Where to take it | Why it decides the fit |
|---|---|---|
| Shaft diameter | Across the output shaft, at the point the pulley or coupling sits | A pulley bored for one diameter will not clamp on another |
| Shaft length | From the crankcase face to the shaft end | Too long fouls the driven unit; too short leaves no engagement |
| Keyway | Width and depth, and its position along the shaft | Without a matching keyway the drive will slip under load |
| Bolt-hole spacing | Centre to centre, in both directions, on the base | The engine has to sit on the existing frame or plate |
| Shaft centreline height | From the mounting face up to the shaft centre | Sets the pulley alignment; small errors destroy belts |
| Fuel tank and exhaust side | Relative to the driven equipment | Decides whether the engine fits inside the existing guard |
The EY20 figures quoted above are the maker’s published data for the common variant. Fujiheng does not publish EY20 dimensions: they differ between variants, and a drawing measured from the unit in hand is the only reliable source.
How to choose
Photograph and measure the engine in place
Take the five measurements above with the engine still mounted, and photograph the shaft, the mounting feet and the driven coupling. Measurements taken off the machine are usually wrong by a few millimetres.
Note what the engine drives
A pump, an alternator and a gearbox each load the shaft differently. State the driven equipment and its rated power, not just the engine it replaced.
Confirm the duty
Continuous or intermittent, and how many hours a day. A slightly larger engine running below its rating is normally a better choice than one at its limit.
Compare the drawing, not the name
Send the measurements and ask for a dimensioned drawing of the proposed replacement. Overlay the two before committing to an order.
Decide the starting system
Recoil keeps the installation simple; electric start needs a battery and charging coil, which changes the wiring and the enclosure.
Suited to
- Replacing a failed small petrol engine where the driven equipment is worth keeping.
- Upgrading to a slightly larger engine on equipment that can take the extra weight and bulk.
Not the right choice when
- Matching on model name without measuring — variant dimensions differ.
- Assuming a bigger engine will fit because the power figure is close.
How this is checked before it ships
The smallest engine we publish
Our range starts at the FSH160: 163 cc, 5.5 HP / 3.1 kW, 16 kg net. It is the model to compare against when an EY20-class engine is being replaced and more output is acceptable.
Drawings before quotations
Data sheet and drawing for the specific build are issued with the quotation on request, and every unit is tested before packing.
More on the production sequence and the documents issued with an order: certifications, testing and quality control.
Models and pages referred to in this guide
About this guide
- Prepared by
- Fujiheng technical sales team
- How the figures were checked
- Figures cross-checked against the printed catalogue row for each model. Third-party engine figures are taken from the maker’s published data and labelled in the text.
- Last reviewed
- 2026-10-20
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Contact
Tell us what you need
Send us your market, required output and configuration and we will come back with a suitable model and quotation. We reply to enquiries within one working day.
- Telephone
- 0086-18662020695
- Factory and office
- Yancheng Fujiheng Power Machinery Co., Ltd.
Teyong Industrial Park, Sheyang County, Yancheng, Jiangsu, China
Teyong Industrial Park, Sheyang County, Yancheng, Jiangsu, China
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