The Bobcat 743 skid steer loader remains one of the most recognized compact machines from the 1980s and early 1990s. At its heart sits the Kubota V1702 diesel engine—a workhorse that continues to power equipment across job sites today. If you own a 743 or are considering one, understanding this engine inside and out will help you keep it running or make smart decisions when replacement time comes.
Key Takeaways
- The Bobcat 743 is powered by the Kubota V1702 diesel engine, producing approximately 36 HP at 2,800 RPM, and remains popular in 2024 for its reliability and straightforward mechanical design.
- The 743 engine holds around 2.2 gallons of engine oil, pairs with a 23-gallon fuel tank capacity on the machine, and uses standard diesel fuel—giving operators a full workday of run time under moderate load.
- The Kubota V1702 appears across multiple brands including Bobcat, Case, Gehl, Mustang, and New Holland, which means parts and remanufactured engines are still readily available through dealers and diesel specialists.
- Drop-in remanufactured V1702 engines come fully assembled and dyno tested, allowing contractors and owner-operators to minimize downtime compared to in-house rebuilds.
- This guide covers basic troubleshooting for issues like hard starts and overheating, maintenance intervals, and answers to common questions about rebuilding or replacing a Bobcat 743 engine.
Overview of the Bobcat 743 and Its Engine
The Bobcat 743 skid steer loader was a mainstay model built from the mid-1980s through the early 1990s. Its compact size and reliable performance made it a favorite for construction, agriculture, and landscaping applications. The machine’s capability is built around one key component: the Kubota V1702 diesel engine.
Some documentation and online sources incorrectly refer to this powerplant as the “V1720,” but the correct Kubota designation for the Bobcat 743 is the V1702—a 4-cylinder, liquid-cooled diesel. This distinction matters when you’re sourcing parts or a replacement engine.
Core engine specifications at a glance:
- Approximately 36 HP at 2,800 RPM
- Four-stroke, naturally aspirated design
- Indirect injection with mechanical fuel system
- Liquid cooling system
The Bobcat 743 delivers a rated operating capacity of about 750 lb and a maximum travel speed near 6 mph. These numbers give context for how the V1702’s power translates into actual work—enough muscle for loading, grading, and material handling without the bulk of larger machines.
Kubota V1702 Engine Specifications in the Bobcat 743
This section breaks down the technical specs of the V1702 as installed in the Bobcat 743. Whether you’re comparing to other machines, confirming compatibility for a swap, or simply want to verify what you’re working with, these numbers provide the reference points you need.
Power Output
The V1702 produces approximately 36.0 HP at 2,800 RPM in the Bobcat 743 configuration. This is the factory-rated gross horsepower. Peak torque arrives lower in the RPM range—around 80 foot-pounds at 1,600 RPM—which means the engine is optimized for sustained work at moderate speeds rather than high-revving performance.
Displacement and Cylinder Arrangement
- Displacement: approximately 1.7 liters (104 cubic inches)
- Configuration: 4-cylinder inline
- Bore and stroke: 3.2 inches each (square engine design)
- Compression ratio: 21:1
- Firing order: 1-3-4-2
The square bore-to-stroke ratio indicates a balanced design favoring broad torque delivery across the operating range.
Lubrication System
- Engine oil capacity: approximately 2.2 gallons (9 quarts with filter)
- Recommended oil: Diesel-rated engine oil such as 10W-30 or 15W-40 meeting current API specifications
- Always refer to the operator’s manual for viscosity recommendations based on your climate
One important note: the V1702 requires diesel-specific engine oil, not standard automotive oil. Diesel engine oil contains detergents formulated to manage combustion byproducts and maintain engine cleanliness over time.
Cooling System
- Type: Liquid-cooled
- Coolant capacity: approximately 3.2 gallons (12.3-13 quarts)
The liquid cooling system handles heat dissipation more effectively than air-cooled alternatives, which is critical in the compact engine bay of a skid steer where space constraints limit airflow.
Fuel System
The Bobcat 743’s fuel tank capacity sits at approximately 23 gallons (about 87 liters). Paired with the V1702’s fuel efficiency, this typically yields a full workday of operation under moderate load before refueling becomes necessary.
Hydraulic System Support
The engine powers a hydraulic system that delivers:
- Pump flow: 11.0 GPM (gallons per minute)
- Relief pressure: approximately 2,100 psi
These numbers show how the engine’s 36 HP and 80 ft-lb of torque translate into lifting force and auxiliary function capability—supporting a tipping load around 2,600 lb and a rated operating capacity of 1,300 lb at 50% tipping.
Key Dimensions
For swaps and rebuilds, keep these high-level dimensional considerations in mind:
- Overall machine length: 120.4 inches
- Overall machine width: 55.1 inches
- Operating weight: approximately 4,720-4,810 lb (depending on configuration and fluid levels)
The compact four-cylinder design was specifically chosen to fit within these tight constraints while delivering adequate power.
Applications and Cross-Compatibility of the Kubota V1702
The V1702 is not unique to the Bobcat 743. Kubota designed this engine for a wide range of compact industrial applications, which works in your favor when sourcing parts or replacement engines in 2024.
Equipment types commonly powered by the Kubota V1702:
- Skid steer loaders
- Compact excavators
- Small agricultural tractors
- Scissor and boom lifts
- Industrial sweepers
- Compact generators
OEM brands that have used the V1702 or close variants:
- Bobcat
- Case
- Gehl
- Mustang
- New Holland
- Various other compact equipment manufacturers
This cross-compatibility means long-term parts support remains strong. Cylinder heads, injection pumps, water pumps, and gasket sets are commonly stocked by diesel specialists who serve multiple equipment brands.
When sourcing a replacement V1702 for a Bobcat 743, verify these key details:
- Engine rotation direction
- Flywheel housing style and bolt pattern
- Accessory bracket configurations
- Fuel system components and hookups
Confirming these specifications ensures a true “drop-in” fit without unexpected modifications.
Remanufactured "Drop-In" Bobcat 743/ Kubota V1702 Engines
A “drop-in” remanufactured V1702 is a fully assembled long block or complete engine that directly replaces the original Bobcat 743 powerplant. For many owners, this option offers the fastest path back to productive operation.
What Gose Into a Quality Reman Engine
Reputable rebuilders with decades of experience in skid steer and compact equipment engines follow a thorough process:
- Complete teardown and inspection of the core engine
- Machining of all critical surfaces (block deck, cylinder bores, crankshaft journals)
- Replacement of wear components: pistons, rings, bearings, seals, valves, and valve guides
- Reconditioning or replacement of the injection pump and injectors
- Full gasket set installation
Dyno Testing Before Shipment
Quality remanufactured V1702 engines are dyno tested before shipping. This verification process checks:
- Oil pressure at operating temperature
- Coolant system integrity
- Power output against specifications
- Absence of leaks
Documented test results give buyers confidence that the engine will perform correctly once installed.
What Arrives and What You Do
A true drop-in engine arrives fully assembled with major accessories (depending on the supplier), ready to bolt to the Bobcat 743’s existing mounts. After installation, owners typically need to:
- Add engine oil and coolant
- Prime the fuel system
- Follow the recommended break-in procedures
This approach minimizes downtime compared with a full in-house rebuild that requires sourcing individual components and machine shop work.
Availability and Warranties
V1702 reman engines are commonly stocked for fast shipment across North America. Lead times can vary depending on core supply and optional configurations. Many suppliers offer 12-month or 1,000-hour warranties, though terms vary—always confirm coverage details before purchasing.
Bobcat 743 Engine Maintenance and Common Issues
Consistent maintenance is essential for extending the life of the Kubota V1702 in a Bobcat 743. Many of these machines are now several decades old, which means deferred maintenance can accelerate wear significantly.
Recommended Service Intervals
|
Service Item |
Interval |
|---|---|
|
Engine oil and filter change |
Every 100-200 operating hours |
|
Fuel filter replacement |
Every 200-400 hours or as needed |
|
Air filter cleaning/replacement |
Daily inspection; replace as needed |
|
Coolant change |
Per manufacturer schedule (typically annually or biannually) |
|
Hydraulic filter service |
Every 250-500 hours |
Common Wear and Failure Points
Older 743 engines frequently exhibit these issues:
- Hard starts: Often caused by worn injectors, low compression, or glow plug failures—especially noticeable in cold weather
- Leaking rear main seal: A common oil leak source on high-hour engines
- Tired water pumps: Weeping seals or bearing noise indicating imminent failure
- Radiator and cooling system problems: Overheating from debris clogging the radiator and hydraulic oil cooler fins
- Injection pump and injector issues: Caused by contaminated diesel or skipped fuel filter changes
Troubleshooting by Smoke Color
The color of exhaust smoke provides diagnostic clues:
|
Smoke Color |
Possible Causes |
|---|---|
|
White smoke on cold start |
Glow plug failure, low compression, timing issues |
|
Black smoke under load |
Restricted air filter, injector problems, overfueling |
|
Blue smoke |
Oil consumption from worn rings or valve guides |
Monitoring During Operation
Keep an eye on the engine oil pressure and coolant temperature gauges while operating. Deviations from normal readings in a Bobcat 743 can signal developing problems long before catastrophic failure occurs. If pressure drops or temperature climbs unexpectedly, shut down and investigate before continuing.
For any in-frame rebuild or top-end repair on the V1702, following the factory service manual for torque specs and procedures is essential. Incorrect assembly can lead to premature failure or additional damage.
Choosing Between Rebuilding and Replacing a Bobcat 743 Engine
Owners of older Bobcat 743 loaders often face a fundamental decision: rebuild the original V1702 or install a remanufactured replacement? The correct answer depends on your specific situation.
When an In-House or Shop Rebuild Makes Sense
- The engine core is in good condition with no major block or crankshaft damage
- You have local access to a reputable machine shop with diesel experience
- You want direct control over component selection and quality
- Time pressure is minimal and cost savings are the priority
When a Drop-In Reman Is the Better Choice
- The engine has suffered catastrophic failure (broken connecting rods, cracked block, spun bearings)
- Local diesel expertise is limited or unavailable
- Rapid turnaround is more valuable than marginal cost savings
- You prefer a warranty-backed solution with documented test results
What a Full Rebuild Typically Includes
Whether performed in-house or by a professional rebuilder, a comprehensive V1702 overhaul covers:
- Block cleaning and inspection
- Cylinder honing or boring as needed
- New pistons, rings, and wrist pins
- Main and rod bearing replacement
- Camshaft bushing inspection or replacement
- Full gasket and seal set
- Crankshaft inspection, grinding, or replacement
- Cylinder head reconditioning (valves, guides, seats)
- Injector and injection pump reconditioning
Consider the Whole Machine
Before investing heavily in the engine, evaluate the overall condition of your Bobcat 743:
- Hydraulic system health
- Drive chain wear
- Frame and structural integrity
- Cab and controls condition
- Projected remaining useful hours
If the machine has significant wear in multiple systems, an expensive engine rebuild may not be the best use of funds. Conversely, a solid machine with a tired engine is an excellent candidate for a reman powerplant that can add years of productive life.
When selecting any engine supplier or rebuilder, compare warranty coverage, parts availability, and support. Ask for documented dyno test results for remanufactured units—reputable suppliers provide this information without hesitation.
FAQ
What type of oil does a Bobcat 743 engine use, and how often should it be changed?
Most owners use high-quality diesel-rated engine oil such as 10W-30 or 15W-40 meeting current API specifications. The correct capacity is approximately 2.2 gallons for the Bobcat 743 installation. Oil and filter changes should occur roughly every 100-200 operating hours—or more frequently in dusty or severe conditions. Always refer to the original Bobcat or Kubota maintenance schedule where available for specific guidance.
How can I tell if my Kubota V1702 engine in a Bobcat 743 is nearing the end of its life?
Watch for these warning signs: noticeable loss of power, excessive blow-by from the crankcase breather, blue or white smoke that doesn’t clear after warmup, high oil consumption, low compression readings across cylinders, and steadily dropping oil pressure. A compression test and oil analysis are cost-effective diagnostics that help you decide whether to plan an in-frame overhaul or budget for a full replacement.
Can I swap a different engine into my Bobcat 743 instead of the V1702?
Some fabricators have adapted alternative engines, but a non-V1702 swap typically requires custom motor mounts, bellhousing modifications, drive system changes, exhaust and intake rerouting, and potential cooling system upgrades. For most owners, staying with a Kubota V1702-based drop-in remanufactured engine is the most straightforward and cost-effective path. The added complexity of a different engine rarely justifies the effort unless you have specific performance requirements.
Is it safe to run biodiesel in the Bobcat 743's Kubota V1702 engine?
Limited biodiesel blends (such as up to B5) are generally acceptable in older mechanical-injection diesels if the fuel meets quality standards. Higher biodiesel concentrations can soften older fuel hoses and seal materials over time. If you plan to use biodiesel, confirm with the latest Kubota or Bobcat guidance and inspect fuel system components regularly. Proper storage practices are especially important with biodiesel, as it has a shorter shelf life than petroleum diesel.
Where can I find parts for a Bobcat 743 / Kubota V1702 engine today?
Parts remain readily available through multiple channels: authorized Bobcat dealers, independent diesel engine specialists, and online suppliers focusing on Kubota industrial engines and compact equipment components. Thanks to the V1702’s widespread use across multiple equipment brands, common parts are well-stocked:
- Overhaul gasket kits
- Pistons and ring sets
- Main and rod bearings
- Injectors and injection pump components
- Water pumps
- Glow plugs
- Filters (oil, fuel, air)
- Drive belts
For hard-to-find items or technical questions, reaching out to specialists via phone or email often yields faster results than searching generic parts websites. Many suppliers maintain inventories specifically for legacy Kubota engines and can provide the information you need to verify correct part numbers for your application.
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