Spring starter motors
Simple, mechanical, and built for total independence, for engines up to 14 litres.
Powerstart’s SureStart spring starter motors are a reliable, cost-effective way to start diesel engines up to 14 litres by hand, with no battery, air or hydraulics. Because they’re pre-engaged, they’re also ATEX compliant for hazardous areas. Coming in six different model sizes, they deliver reliability through simplicity.
To start an engine you simply wind the handle to energize the spring. When the trip lever is pushed the starter motor turns the engine. It is that simple.
SureStart spring starters are perfect for harsh environments and hazardous areas such as offshore and marine applications, as they are unaffected by damp conditions.
Spring starter models
Model
Max Engine Size
Max Torque
S20
0.5 to 2.0 litres
91 Nm
S30
1.1 to 6.6 litres
115 Nm
S40
1.3 to 7.8 litres
126 Nm
S50
Up to 10 litres
94 Nm
S60
Up to 12 litres
140 Nm
S70
Up to 14 litres
147 Nm
Spring starter specifications
| Model | Engine capacity | Max torque at pinion | Max winding handle torque | Turns to fully charge | Weight | Mounting |
|---|---|---|---|---|---|---|
| S20 | 0.5 to 2.0 litres, up to 4 cylinders | 91 Nm (71 lb ft) | 64 Nm | 10.75 | 12 kg (26.5 lb) | Flange, SAE 1, SAE 2 |
| S30 | 1.1 to 6.6 litres, up to 6 cylinders | 115 Nm (85 lb ft) | 64 Nm (47 lb ft) | 11.5 | 16 kg (35.3 lb) | Flange, SAE 1 to SAE 4 |
| S40 | 1.3 to 7.8 litres, up to 6 cylinders | 120 to 126 Nm (89 to 93 lb ft) | 81 Nm (60 lb ft) | 10.5 | 18 kg (39.7 lb) | Flange, SAE 1 to SAE 4 |
| S50 | 1.5 to 9.0 litres (6 cyl), 1.25 to 10.0 litres (8 cyl) | 90 to 94 Nm (66 to 69 lb ft) | 81 Nm (60 lb ft) | 14.5 | 21.5 kg (47.4 lb) | Flange, SAE 1 to SAE 3 |
| S60 | 2.0 to 12.0 litres (6 cyl), 1.5 to 12.0 litres (8 cyl) | 94 to 140 Nm (69 to 104 lb ft) | 81 Nm (60 lb ft) | 16.5 | 28 kg (61.7 lb) | Flange, SAE 1 to SAE 3 |
| S70 | 2.0 to 12.0 litres (6 cyl), 1.75 to 14.0 litres (8 cyl) | 147 Nm (108 lb ft) | 95 Nm (70 lb ft) | 19.5 | 28 kg (61.7 lb) | Flange, SAE 1 to SAE 3 |
Every model engages in 1.75 turns, and the winding handle can be set in 8.5° steps. Torque ranges depend on the specific model variant. A starting aid is recommended below 5°C. Full specifications, pinion options and finishes are on each model page. Not sure which size fits? Send us the engine make, model and capacity and we will confirm it.
Spring starters for hazardous areas
In a zoned area, the feature that matters is the pre-engaged design. A Powerstart spring starter meshes the pinion with the flywheel ring gear before it turns the engine, so there is no impact engagement of the kind an inertia starter makes. Add in the fact that there is no battery, no electrical circuit, and no stored air or hydraulic pressure anywhere in the system, and a spring starter removes the usual ignition sources from engine starting altogether.
That is why they are specified for offshore and marine installations, emergency vessels and black start duty in potentially explosive atmospheres. For the difference between the two certification schemes, see ATEX vs IECEx engine starters, or read how a spring starter works.
Advantages
Powerstart spring starters require no external power source — no air, hydraulics, or electrics — delivering complete independence in any location.
Mechanical simplicity means fewer moving parts, reduced maintenance, and instant readiness, even after long periods of inactivity.
Compact, durable, and field-proven, they’re ideal for remote, emergency, and standby equipment where dependable manual starting is essential.
Frequently asked questions
What size diesel engine will a spring starter start?
The six SureStart models cover diesel engines from 0.5 litres up to 14 litres. The S20 suits engines of 0.5 to 2.0 litres with up to four cylinders, and the S70 takes eight-cylinder engines up to 14 litres. The table above gives the range for each model.
Does a spring starter need any power supply?
No. A spring starter is wound by hand and releases its stored energy when the trip lever is pushed. There is no battery, air or hydraulic supply, so it is ready to start after long shutdowns and in damp or cold conditions.
How many turns does it take to wind a spring starter?
Every model engages in 1.75 turns. A full charge takes from 10.5 turns (S40) to 19.5 turns (S70). The winding handle position can be set in 8.5 degree steps to suit the installation.
Are spring starters suitable for hazardous areas?
Yes. Powerstart spring starters are pre-engaged, so the pinion meshes with the ring gear before the engine turns, and there is no electrical circuit or stored pressure in the system. See ATEX vs IECEx engine starters for how the certification schemes differ.
Do spring starters work in cold weather?
Yes, a spring starter is not affected by cold the way a battery is. Below 5°C a starting aid is recommended so the engine fires on the first attempt.