Yanmar YT359 specifications

YT359 travel limits, throttle boost and anti-stall are separate controls

The YT359's i-HMT controls let engine speed and ground speed serve different parts of a job. A machine that changes travel speed under load is not necessarily losing engine output. Establish its selected range, A/B preset and anti-stall state before interpreting that behavior.

A/B presets belong to the selected range

Yanmar's quick guide gives both A and B presets in the first and second ranges, but only A in the third. Moving the range lever selects the stored presets for that range. The adjustment must also be made with that range selected.

A setting remembered from another range does not establish the limit currently in use.

The same guide says anti-stall reduces travel speed when engine speed drops under load, and resumes travel as engine speed recovers. The panel displays an arrow while this reduction operates. That indicator helps distinguish a commanded response from an unexplained loss of drive.

The travel ceiling and PTO setting have different purposes

Yanmar's A/B explanation uses a tractor symbol for travel-speed adjustment and a tachometer symbol for engine-speed adjustment. The fully depressed pedal reaches the selected travel ceiling, subject to the available engine-speed setting. A slow demonstration may therefore be showing a preset rather than the transmission's unrestricted speed.

Its PTO setup uses the engine-speed selection and the PTO display. This lets an operator choose the shaft speed required by an implement while choosing ground speed separately. Preserve those two settings when comparing repeated passes.

Throttle boost adds engine speed without commanding faster travel

The manufacturer locates the boost button on the loader joystick. Holding it raises engine speed toward the maximum selected in A/B mode while maintaining ground speed. For loader work in a confined building, this changes the available engine response without requiring a faster approach to the load.

Boost should not be described as a larger loader-capacity rating. Its control function and the loader's published load limits answer different questions. The quick guide also excludes throttle boost in the third range, so a demonstration there cannot establish that the button is defective.

The manufacturer distinguishes working-speed and stationary PTO power

The 2022 brochure publishes different PTO-power figures at working speed and at zero travel speed. Its YT359 gross-engine figure is also different from the secondary record retained below. Keep the measurement condition beside each figure rather than combining the larger power claim with another test condition.

The ROPS and cab configurations also have separate equipped weights.

Set up the YT359's i-HMT controls for the job

Yanmar's YT347/359 quick guide distinguishes A/B presets from cruise control. A/B selection stores an engine-speed setting and a maximum travel speed for the selected range. Cruise holds an established forward travel speed instead. Switching A/B settings is unavailable during cruise, so these controls should not be demonstrated as interchangeable ways to change speed while mowing.

The guide provides paired presets in the lower ranges but only the A preset in the highest range. To change a range's stored values, the range lever must already be in that position. A seller demonstrating only one range has not shown that the other stored settings suit your loader or implement work.

Throttle boost works while its button is held and increases engine speed without increasing travel speed. It is unavailable in the highest range. Anti-stall has a different purpose: it reduces travel as engine speed falls under load, then resumes travel as the engine recovers.

Establish which function is active before treating a change in forward speed as a transmission fault.

Warm the shared transmission and hydraulic oil

The manufacturer's operator-manual extract says the transmission hydraulic oil also serves the i-HMT. In cold conditions, warming the engine alone for an arbitrary moment does not establish that this shared oil is ready for implement operation. The extract gives a temperature-dependent warm-up schedule and explains that cold, viscous oil circulates poorly.

Its operation instructions also require a complete stop before moving the range selector or the two-wheel/four-wheel-drive lever. Variable travel within a selected range does not make those mechanical selections equivalent to the continuously variable pedal function. Use the range lever at rest, rather than testing it as an on-the-move shift.

Compare PTO ratings at the stated operating condition

The 2019 specification sheet publishes separate YT359 PTO outputs at working speed and at zero speed. The engine's gross rating is a third measurement. A rotary implement comparison must use the relevant PTO condition; neither a gross-engine figure nor a differently scoped reference listing is a substitute for that output.