Need an engine for a John Deere 790? The original 3TNE84 is an 84 mm Yanmar, and the 88 mm 3TNV88 is the replacement core that goes in its place. We hold it in both mechanical and common rail, new surplus and rebuilt, and we set it up to your compact utility tractor.
The John Deere 790 is a compact utility tractor built for small-acreage, property maintenance and light loader work. It is one of the most widely sold Yanmar 84 mm-bore applications in the United States.
ENGINE SPECIFICATION. Three cylinder, four cycle, liquid cooled, vertical in-line. Direct injection, naturally aspirated. Bore and stroke 88 x 90 mm. Displacement 1.642 L (100.2 cu in). Around 36 hp at 3000 rpm at full speed, less in machines governed lower. Dry weight approximately 341 lb (154 kg). Rotation counterclockwise viewed from the flywheel end. Engine as fitted to this machine: Yanmar 3TNE84. Production years: 1998-2005. Rated output in this machine: approximately approx. 30 hp.
WHAT WE FIT TO YOUR MACHINE.
On a compact tractor the engine bolts to the transmission housing and drives the PTO. The bellhousing, flywheel, PTO drive, oil pan and front pulley all have to match your tractor - these are external components and they carry over from the engine you are removing.
WHY THE 3TNV88 REPLACES THE 3TNE84.
Yanmar's TNV three-cylinder engines are one family on one architecture - same 90 mm stroke, same block design, same mounting and accessory layout. Only the bore changes: 82 mm (3TNV82A, 1.331 L), 84 mm (3TNV84 and 3TNE84, 1.496 L) and 88 mm (3TNV88 and 3TNE88, 1.642 L). Because the 84 mm and 88 mm engines share the same core and the same mounting layout, the 3TNV88 is the established replacement where an 84 mm engine is no longer available. 3TNE is the earlier generation; 3TNV is the current-production successor.
Before it ships we confirm the mounting points, bellhousing and SAE housing, flywheel, oil pan clearance, PTO and pump drive, throttle linkage and wiring against your machine.
MECHANICAL OR COMMON RAIL - THIS IS THE ONE THING YOU MUST MATCH.
The Yanmar 3TNV88 comes in two fuel systems and they are not interchangeable. MECHANICAL INJECTION uses a mechanical pump and governor, with no ECU or sensors - this is what most machines in the field run, and it is our standard stock. ELECTRONIC COMMON RAIL (HPCR) is ECU-controlled, fitted to machines built to the later emissions standards. We carry both, in new surplus and rebuilt.
The suffix on your data plate - codes like -BKMS, -BPTB2, -QTB - does not mean a different engine. The core is the same across the family: same block, same crank, same 88 x 90 mm bore and stroke, same 1.642 L. The suffix tells you the fuel system and the accessory package. The accessories are external and swap; the fuel system is what has to match.
Two other variants to know about: the 3TNV88F has an ELECTRONIC GOVERNOR with EGR and is a different engine again, and the 3TNV88-GGE is a fixed-speed GENERATOR engine, not a machine engine. There is also a 4-CYLINDER 4TNV88 that is not the same as this three-cylinder engine at all.
Full breakdown of every variant, and how to read your data plate: see our Yanmar 3TNV88 engine buying guide.
BEFORE YOU ORDER.
Send the data plate off your John Deere 790 - model number, suffix, serial. We will confirm whether you need mechanical or common rail, check the cylinder count, tell you what bolts across from the engine you are removing, and quote you on the correct core. New surplus and rebuilt both available.