what about replacing zincs?

[Craig]

this mixing elbow thing got me into my yanmar owners manual. according to the book it says my 3gm has 3 zincs. it looks like one is in the rear of the cylinder head and two are in the left side of the block.(looking back at the engine) first off does this sound right, what do they look like and should they be replaced? it says if 1/2 of the zinc is gone replace it. also after every 500 hours. right out of the manual. do people really do this? thanks and have a great holiday from s/v respite on the hard.

 

[Steve Dion]

What book are you referencing?

Craig:I am checking the Yanmar manual and there are engine drawing for 1GM10, 2GM20, 3GM30, 3HM35, 2GM20F 3GM30F, 3HM35F. The models that end with the F are the Fresh Water cooled units. Chapter 7 is for the Direct Sea-Water Cooling System maintenance and refers to anticorrosion Zinc. Chapter 8 is for the Fresh Water Cooling System. There is NO reference to the zincs in Chapter 8.Both engines have a sea water pump. The Fresh water cooled engine also has a Fresh Water Pump.

 

[Bob Keller]

No zincs for 3GMF

I recently took a basic Yanmar class at Mack Boring in NJ and learned, s Steve noted, there are no zincs in the fresh water cooled version of the this engine. Hope that solves the confusion.

 

[Craig]

my book

i have a yanmar operation manual that came with my boat. on the cover it says 1gm10 2gm20(f) 3gm30(f) and 3hm35(f) chapter 7 relates to method of operation per my index and chapter 8 relates to storage.off hand i dont see any publishing dates.