S-739 Lever Action Grease Gun

Frequently Asked Questions: S-739 Italian Model Lever Action Grease Gun (600 g, 700 cc, Variable Stroke, 10,000 PSI)

What is the S-739 Italian Model and what makes it different from the other STAR lever grease guns?

The S-739 is the only STAR lever grease gun built for the 600 g Italian-standard grease cartridge format, with a wider 59.7 mm (2-11/32") barrel, 700 cc (23.6 oz.) bulk capacity, variable stroke action, and 10,000 PSI pressure rating. The rest of the STAR 14 oz./400 g lever-action range uses the 57.15 mm worldwide-standard barrel with 400 g DIN 1284 Euro-Cartridge compatibility and 500 cc bulk; the S-739 is the Italian-cartridge-specific SKU built for Italian workshops, Italian-equipment global service networks, and global fleet operators that have standardised on 600 g cartridge supply chains. Three features together define it: Italian 600 g cartridge format, 40% larger 700 cc bulk capacity, and variable-stroke action for tight-access service.

What is an Italian 600 g grease cartridge and is it different from standard 14 oz (400 g) cartridges?

Yes, the Italian 600 g cartridge is a distinct cartridge format with a larger diameter and more grease per cartridge than the 400 g DIN 1284 Euro-Cartridge worldwide standard. A 600 g cartridge holds approximately 50% more grease than a 400 g cartridge, and its larger outer diameter requires a wider barrel bore (the S-739 uses 59.7 mm vs the 57.15 mm standard). The Italian cartridge format is stocked throughout Italian grease-supply distribution, in authorised Italian-equipment service networks across Europe and globally, and in a number of Latin American and Asian markets where Italian-origin equipment drives cartridge standardisation. Italian and European grease-supply distributors stock both formats; workshops choose based on their existing equipment-supplier cartridge standard. The 600 g format is sometimes informally called the "Italian cartridge" or the "larger European cartridge" to distinguish it from the 400 g DIN 1284 standard.

Can I use standard 14 oz (400 g) cartridges in the S-739?

No. The S-739 is built specifically for the 600 g Italian cartridge format with a 59.7 mm barrel bore. Standard 14 oz./400 g DIN 1284 Euro-Cartridges are narrower in diameter and will not seat properly in the S-739's wider barrel; the cartridge will be loose, air gaps will form between the cartridge and the barrel wall, and priming will fail. Workshops needing 14 oz./400 g cartridge compatibility should select the S-709 Heavy Duty (variable stroke, 400 g, 500 cc bulk, 57.15 mm barrel) or the S-738 Industrial/Commercial (400 g, 500 cc bulk, large prime-retention inlet, 57.15 mm barrel) instead. For bulk fill, all three guns accept bulk-pack grease from 5 kg, 15 kg, or 20 kg pails regardless of cartridge format, so a workshop with mixed supply can still bulk-fill the S-739 from its general grease pail.

What is the advantage of the 700 cc bulk capacity over the 500 cc standard?

The 700 cc reservoir is 40% larger than the 500 cc standard used on most of the STAR 14 oz./400 g range. A 700 cc bulk fill covers roughly 55 typical fittings at 12 g each, versus about 40 fittings for a 500 cc fill. For fleet-maintenance depots, in-plant maintenance teams, lube-truck field service, fast-lube centres, and earth-moving-equipment daily-service routes where greasing volume per shift is the primary workflow constraint, the larger capacity measurably reduces mid-shift refills. The trade-off is a physically larger gun that weighs more when fully loaded (approximately 150-200 g more grease mass than a 500 cc fill) and takes slightly more storage space. For high-volume professional fleet and plant service, the fewer refills pay back; for occasional or light-duty service, the 500 cc standard capacity is sufficient.

How does variable stroke action work on the S-739?

Variable stroke action means the lever mechanism can develop full 10,000 PSI head pressure on partial lever strokes. The operator modulates between two operating modes directly from lever pressure: short-stroke high-pressure mode for stiff or clogged fittings in confined spaces, and full-stroke high-volume mode for open-access multi-point greasing routes. On a short stroke, each partial pump delivers less grease volume but reaches full pressure; useful for clearing stiff fittings in tight engine bays, inside wheel arches, pin bushings, and other restricted-access locations where a conventional full-stroke lever cannot complete a stroke. On a full stroke, each pump delivers the full 1 g per stroke output at the rated pressure; useful for open-access multi-point routes where volume throughput matters. No mode switch, no setting adjustment; the operator reads the fitting, chooses the stroke length, and modulates.

Does variable stroke really help in confined spaces?

Yes, measurably. The primary use-case for variable stroke on the S-739 is greasing fittings where a conventional full-stroke lever cannot complete a stroke because of physical clearance restrictions. Typical scenarios: confined engine bays where the gun handle can only swing through 30-50% of the full lever arc before hitting firewall or engine-block clearance, wheel-arch pin bushings where the gun body has to sit inside the wheel arch, clutch and transmission grease points on heavy equipment where access is through a small service window, and industrial-machinery pivot joints inside guarded assemblies. On conventional fixed-stroke guns, the operator has to remove adjacent components, rotate the equipment, or switch to a pistol-grip backup. On the S-739, the short-stroke variable-stroke action maintains pressure delivery through the restricted arc; the full stroke length is not required to build pressure on the zerk.

How does the S-739 compare to the S-709 Heavy Duty and the S-738 Industrial/Commercial?

All three are 10,000 PSI aluminium die cast head guns, but each targets a different use-case. The S-709 Heavy Duty uses the 14 oz./400 g worldwide-standard cartridge with 500 cc bulk and variable stroke; the correct pick for workshops on the 400 g standard that need variable-stroke tight-access service. The S-738 Industrial/Commercial uses 400 g cartridge with 500 cc bulk and a large prime-retention grease inlet (no variable stroke); the correct pick for 400 g-standardised industrial/commercial fleet service where prime retention on long routes matters more than variable-stroke flexibility. The S-739 uses the 600 g Italian cartridge with 700 cc bulk and variable stroke; the correct pick when the workshop standardises on Italian cartridges or when the 700 cc larger capacity is a priority. Same pressure tier, same head-construction quality, different cartridge formats and different engineering priorities.

What is the difference between the Italian Model and German-style lever grease guns?

The Italian Model uses a 600 g cartridge in a 59.7 mm wider barrel with 700 cc bulk capacity; German-style lever grease guns typically use the 400 g DIN 1284 Euro-Cartridge (the European 400 g standard) in the 57.15 mm standard barrel with 500 cc bulk. The difference is cartridge supply chain: Italian workshops and Italian-equipment service networks stock 600 g cartridges, while German and wider European workshops predominantly stock 400 g DIN 1284 cartridges. Both formats are "European" cartridges in the general sense, but they are not interchangeable. The S-739 is the STAR SKU for the 600 g Italian-cartridge supply chain; the S-736 European Model and S-737 European Model Professional are the STAR SKUs for the 400 g DIN 1284 Euro-Cartridge supply chain. Workshops operating mixed fleets sometimes stock both cartridge formats and both gun types in dedicated roles.

Is the S-739 suitable for professional automotive dealership and fleet-service use?

Yes, particularly for automotive dealerships, authorised Italian-equipment service centres, service shops, and fleet-maintenance operations that have standardised on 600 g cartridge supply or that value the 700 cc larger capacity for high-volume daily service. The S-739 handles automotive chassis service, tractor chassis and combine harvester service, construction equipment, conveyor-line bearings, cement plant and steel mill machinery, pulp and paper rollers, food processing equipment, crane pivot joints, excavator pins and bushings, marine-vessel deck equipment, mining drill-rig maintenance, and general in-plant maintenance. Variable-stroke action extends the use-case into confined-space fittings where conventional lever guns need to be supplemented with a pistol-grip backup. For professional daily-use service where both cartridge format compatibility and 700 cc capacity matter, the S-739 is the specific SKU answer.

Is 10,000 PSI safe for bearing seals during service with the S-739?

Yes. Bearing seals typically fail at internal grease-cavity pressures of 500 to 1,500 PSI, far below the 10,000 PSI maximum the S-739 can develop at a fully blocked fitting. Actual pressure reaching the bearing seal depends on the fitting's flow restriction: a clean zerk on a healthy bearing passes grease at low pressure, the pump never reaches maximum PSI unless the fitting is completely blocked. The 10,000 PSI specification is the maximum the pump can build when the coupler is blocked, not the steady-state pressure reaching the bearing. To prevent over-greasing: stop pumping the moment fresh grease appears at the bearing seal or the lever resistance sharply increases. Over-lubrication prevention is important across the service workflow; over-greasing damages seals, causes bearing overheating, and attracts contamination. Note specifically for variable-stroke operation: over-pressurising with repeated short strokes on a blocked fitting can damage bearing seals; if the fitting will not accept grease within a few strokes, stop and investigate the fitting rather than continuing to pump.

Can the S-739 cause a grease injection injury at 10,000 PSI with variable stroke?

Yes. Variable-stroke short-stroke high-pressure mode builds the full 10,000 PSI peak pressure on every partial stroke, which is the same peak pressure a conventional full-stroke lever gun builds. The injection-injury risk is identical. Grease injection injuries from 10,000 PSI grease guns are documented in emergency medicine. A pinhole in the hose or unseated coupler can drive grease through intact skin at 10,000 PSI; a ruptured hose can project grease at peak pressure across the entire rupture profile, significantly increasing exposure area. Above 7,000 PSI, the likelihood of amputation from fluid injection injury escalates significantly if treatment is delayed. The initial wound looks like a tiny puncture and often does not hurt much initially; grease migrates along tissue planes and causes chemical damage over 24-72 hours. Go to an emergency department immediately for any suspected injection injury, brief the staff it is a high-pressure grease injection (not a simple puncture), and do not wait for pain to develop.

What PPE is required when using the S-739?

Mandatory: wraparound safety glasses (ANSI Z87.1+ impact-rated with side shields), nitrile chemical-resistant gloves, long sleeves, and closed-toe steel-capped shoes at minimum. Safety rules: never point the coupler or flex hose at any body part or another person, keep the non-lever hand behind the coupler head during pumping, inspect the hose and coupler before each use for visible damage (cracks, bulges, stiffening, loose connections), never test grease flow by pressing the coupler against skin or fabric, never use the gun near open flames (grease is flammable at high temperatures), and do not operate the gun in confined spaces without adequate ventilation. Hold the gun safely: dominant hand on the lever, non-dominant hand on the body supporting the weight (particularly important on the S-739 which weighs more fully loaded than 500 cc guns due to the larger 700 cc capacity). Never wrap the gun in rags or plastic bags during use; the packaging can catch on moving equipment and pull the gun unexpectedly.

How do I prime the S-739 after a cartridge change?

Retract and lock the plunger rod, unscrew the barrel at the head-to-barrel joint, insert the 600 g Italian cartridge nose-first with both seals peeled, screw the head back on, release the plunger rod from the friction-lever side-slot lock. The extra-heavy follower spring compresses the grease column against the head. Crack the air bleeder valve a quarter turn to release trapped air, then pump the lever 3 to 5 full strokes with the coupler disconnected until grease flows cleanly from the nozzle without air bubbles. Close the bleeder valve. First-use priming on a new gun may take 5-8 strokes because the internal cavity is completely empty. If priming fails after 5 strokes: check the plunger rod is fully released, inspect the cartridge seating for air voids at the cartridge-head interface, and in cold weather allow the grease 5-10 minutes to warm to ambient before priming. The larger 700 cc reservoir typically primes more reliably than smaller-capacity guns because the follower plate maintains a larger grease column in motion during priming.

Does the larger 700 cc capacity reduce air lock and prime-loss problems?

Generally yes. The larger 700 cc reservoir holds a longer grease column, which means the follower spring is working against more grease mass for a larger portion of the total reservoir drawdown before follower pressure drops to problematic levels. Prime loss on lever grease guns typically happens at the one-quarter-to-one-third-empty point because the follower-spring pressure drops as the grease column shortens. On 500 cc guns, that point is hit at roughly 125-170 cc of grease remaining; on 700 cc guns, it's hit at roughly 175-230 cc of grease remaining, so the operator has more grease delivered before prime-retention engineering matters. The S-739 also uses an extra-heavy follower spring specifically sized for the longer 700 cc grease column, which further defers the prime-loss point. Combined with the air bleeder valve and the machined non-return valve, the S-739 has fewer air-lock and prime-loss interruptions than standard-specification 500 cc lever guns across long greasing routes.

How should I store the S-739 between service shifts?

For storage under 30 days: leave grease in the gun, retract and lock the plunger rod, cap the coupler nozzle, store horizontally in a clean dry area. For storage over 30 days: unscrew the barrel, remove the cartridge or drain the bulk reservoir, wipe the barrel interior with a lint-free rag dampened with mineral spirits, dry completely, reassemble with a light film of grease on the plunger-rod seal, cap the coupler, and store horizontally. Always store out of direct sunlight to prolong powder-coat and hose-rubber lifespan. Store grease guns in fireproof cabinets for fire-safety-conscious workshops (grease is flammable at elevated temperatures). Store nozzle-end-down only if the workshop policy requires it; otherwise horizontal is preferred to keep the follower-plate seal evenly loaded. Never wrap the gun in rags or plastic bags for storage (the packaging can trap moisture against the powder-coat finish); a dedicated carrying case or open tool rack is the correct storage approach. For extended seasonal storage, disengage the plunger-rod lock so the follower spring is relaxed; this extends spring service life across multi-year storage cycles.

Is the S-739 available for OEM and private-label orders for Italian and European distributors?

Yes. OEM and private-label manufacture is available on the S-739 for Italian grease-supply distributors, authorised Italian-equipment service networks, European wholesale trade, and global Italian-cartridge distributor trade. Options include custom branding, packaging design for Italian retail or industrial-supply format, BSPT/NPT/M10 thread variants, bright-metal or zinc-plated handle finish, carrying case options, and custom kit configurations per distributor agreement. MOQ 1000 applies as the baseline; higher customisation levels may have higher MOQ thresholds. Factory-price indicative ranges span 600cc, 700cc, and 900cc capacity SKUs across the STAR lever-action range, with the S-739 at 700 cc positioned between the 500 cc standard and the 900 cc extra-large capacity tier. Distributor unboxing and product-presentation material for the 700cc grease gun (retail display, carrying-case options, demonstration kits) is available on request through the STAR Italian-distributor partner programme. Shipping is sea freight to Gioia Tauro, Genoa, Livorno, Trieste, Rotterdam, Hamburg, Antwerp, Felixstowe, and other Italian and European hub ports, with mixed-container consolidation with other STAR products possible to hit MOQ thresholds economically. Global export destinations include Italy, UK, Germany, France, Spain, Poland, Russia, Turkey, Scandinavia, Saudi Arabia, UAE Dubai, South Africa, Kenya, Nigeria, Brazil, Mexico, Indonesia, Philippines, Vietnam, Australia, New Zealand, and worldwide. Contact the STAR export team for Italian-distributor pricing, international shipping coordination, lead times, catalogue requests, and packaging specifications. Made in Ludhiana, Punjab, India, exported to 27+ countries since 1980.