1. Home
  2. DC Power
  3. Alternators and Regulators
  4. Pulley Kits
  5. Serpentine belt kits for Yanmar engines
  6. 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

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

On sale $643.50 $566.99
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 there is no freshwater pump.  The engines have direct salt water cooling.   The salt 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 6 series or XT series 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 to purchase a different alternator pulley 48-AM-106 and you may need to change the length of the belt.

Notice in the photo how the adjustment arm goes.  If you wanted to use a Balmar adjustment arm you would get the UBB and space it out from the engine using the Balmar spacers.  (not sure what offset is required - if you want to try this buy one of each)

Related Items

Spare Serpentine Belt
Some sizes in stock

Recently Viewed Items