This genuine Yanmar multi-rib belt is used to drive the alternator on selected Yanmar engines fitted with a high-output alternator.

The belt is suitable for 2YM15 and 3YM20 engines from specific serial numbers, and for selected 4JH common rail engines when fitted with a second alternator setup.

A worn or slipping alternator belt can cause poor battery charging, belt noise or visible belt wear. Replace the belt during service or when signs of cracking, glazing or slipping are visible.

Always check the engine model, alternator type and serial number before ordering.

Compatible engines

Yanmar 2YM15
Yanmar 3YM20
Yanmar 4JH45-CR
Yanmar 4JH57-CR
Yanmar 4JH80-CR
Yanmar 4JH110-CR

Important compatibility notes

Suitable for 2YM15 from serial number E05888.
Suitable for 3YM20 from serial number E20848.
Also used on 4JH45, 4JH57, 4JH80 and 4JH110 engines with second alternator setup: 12V / 120A or 24V / 60A.

Product data

Brand
Yanmar

Condition
New

Product type
Service part

Part category
Belts

Belt type
Multi-rib belt

Part number
128790-77580

Engine series
YM series, 4JH common rail series

yanmar 4jh belt

Multi-Rib Alternator Belt Yanmar 2YM15 / 3YM20 / 4JH-CR – 128790-77580