A/B Mode

Unmatched tractor technology to lighten your workload & make your life easier.

The most asked about feature on the Yanmar YT347 and YT359 tractor models is A/B mode. This mode gives you the ability to control both engine and travel speed independently. It also offers an unparalleled level of PTO (power take-off) speed control that meets the requirements of multiple attachments. Here’s how it works, why it’s great, and how to set up A/B mode on your tractor.

What is A/B Mode?

A/B mode allows your tractor to travel at two different maximum RPM and travel speeds (Mode A and Mode B). When you use this feature, the tractor will not exceed the maximum travel speed and engine RPM you set it at, even if you move the dash-mounted hand throttle to maximum RPMs (rabbit position).

The Benefits of A/B Mode

The biggest benefit to A/B mode is control. Let’s say that in the 3rd speed range you encounter rough driving conditions and start bumping around in the cab. With a maximum speed of 18 mph in this range, your foot may bounce off the pedal, making the tractor harder to control.

However, if you’ve adjusted the maximum speed in A mode so it never goes more than 10 mph, you’ll have finer control with the foot throttle, resulting in a smoother ride no matter the conditions. You can control this even more by setting your speed to a lower maximum of 6 mph in B Mode.

A second example of how A/B mode could be used is during repeatable tasks such as spraying applications. Say you are pulling a sprayer through your field and need to be able to precisely apply the product at two different rates: standard and heavy application. A/B mode allows you to set the PTO speed to the exact range you want. Set A mode to a travel speed of 6 mph for a standard application rate. Set B mode to 4 mph for a higher application rate.

Now you can easily toggle between the standard and heavy application rates with just the push of a button.

How to Set Up A/B Mode

While A/B mode might sound complicated, it’s extremely easy to set it and forget it. Here’s how to configure your A/B mode.

Instrument Panel

Display the A/B mode screen by either pressing your display’s primary button or by pressing the A/B switch located on the implement control lever. There will be five settings you can choose from. While in first or second range, both the A and the B mode are available; while in third range, only the A mode is available.

Travel Speed

To set the maximum travel speed, the engine and vehicle speed switch must be in the travel positions. This is represented by a tractor icon. Turn the speed setting dial until it reaches your desired speed setting. Note that the travel speed may be limited by the engine speed setting. The tractor will travel at the speed you’ve set when the accelerator pedal is fully depressed.

Engine Speed

To set the maximum engine speed in A/B mode, the engine and vehicle speed switch must be in the engine speed positions. This is represented by a tachometer icon. Once in that position, turn the speed setting dial until it reaches your desired maximum engine speed. To reach the set maximum speed, raise the hand throttle to the maximum position while operating. Travel speed will not be affected while using the hand throttle.

PTO Speed

You can use the PTO RPM setting while the tractor sets the engine speed. To do this, put the engine and ground speed selection switch in the engine speed positions. Then turn the PTO switch to the on position. Once there, turn the speed setting dial to change the display to the PTO setting screen. Turn the dial until you reach the desired maximum PTO speed. Set the hand throttle to the maximum position to reach the desired PTO speed.

A/B Mode with Throttle Boost

Another function that works in conjunction with A/B mode is the throttle boost feature. This is great to use while performing loader activities. When using A/B mode at low engine RPMs, throttle boost allows the operator to increase to the maximum engine speed setting immediately. This helps maximize lift capacity. Once loaded, simply release the throttle boost buttons to return to the set travel and engine speed.

Whether you're using the loader, mowing, spraying, tilling, or baling hay, A/B mode enhances your ability to precisely control ground, engine, and PTO speed. It’s a feature unique to Yanmar machines and is a great way to maximize efficiency while ensuring you get the job done right.

Connect With Yanmar

Yanmar has provided the market with a tractor that provides exact PTO speed control, and is unmatched anywhere else in the industry. Properly maintaining your tractor is key to its long-term performance. If you have questions about your tractor’s maintenance schedule, our dedicated Customer Experience Team is here to help. Get maintenance tips or ask about our exclusive offers. Connect with us online or give us a call at 678-551-7369.

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