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Balmar 48-YSP-3GM-C Pulley Kit for Yanmar 3GM, 2GM-20
Balmar 48-YSP-3GM-C Pulley Kit for Yanmar 3GM, 2GM-20

Balmar 48-YSP-3GM-C Pulley Kit for Yanmar 3GM, 2GM-20

On sale $495.00 $443.00
Balmar Altmount Serpentine pulley kit permits mounting a much larger alternator in lieu of the standard model because of its 10 groove serpentine belt - for select Yanmar engines. This kit, model 48-YSP-3GM-C is for a Yanmar 3GM or 2GM-20
p/n: 48-YSP-3GM-C
Availability: In stock

Do not confuse the 2GM20 and the 2GM20-F, they are not the same.      This kit for the Yanmar 3GM and 2GM-20 does not include a water pump pulley because on these engines the water pump gets a separate belt that goes inside the alternator belt.  See photo below:

Yanmar 2GM-20

These pulley kits by Balmar offer the opportunity to install a larger alternator than would otherwise be possible; this kit is for the Yanmar 23GM and 2GM-20.  Alternator upgrades using a single drive belt are limited by the amount of power that can be transferred by the belt but using a multi grooved belt considerably increases the possibilities. The kits include a set of serpentine pulleys for the crankshaft, water pump pulley and alternator. This pulley kit comes with two belts so you have a spare, the alternators need to be purchased separately. If you order an alternator at the same time as the kit it will come with the appropriate pulley pre-installed. 

  • Kit includes two ten groove J10 pulleys
  • Includes also two 32" circumference J10 belts and mounting hardware.
  • See the Additional Information tab for more about belts.
  • Instruction sheet
  • Read my Blog Post about installing one of these kits.
  • Please check your engine model number carefully to ensure you are ordering the correct kit.  


This kit is designed for use with a Balmar alternator. If you want to use it with your stock Hitachi alternator then you also need to purchase the Hitachi Pulley 48-AM-97. This special Hitachi pulley fixes an alignment issue. It may be possible to use the kit with any alternator that has a 17mm shaft diameter, but the fit and alignment is not guaranteed.   Using this kit with other alternators may require you to change the length of the belt.

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