YSM 8 riser nipple, Y25

Feb 11, 2010
44
Pearson and Yamaha Triton , 25II Juneau
My water injection elbow failed on my YSM8, ordered up a new elbow, lower elbow that comes out of the engine and the nipple that goes between them. The nipple on the Y 25 is a lot longer than the one that is shown in the parts manual. The parts guy I am dealing with says that is the only one that Yanmar shows. It is a counter threaded nipple, left thread on one end right on the other so I can't just get a longer standard nipple. The nipple in the boat is 8-9" long the stock one about 2.5". Anybody familiar with this problem and have a Yanmar part number for the longer nipple. It is 6 sided in the middle threaded on each end. I have attached a pic of the parts manual, the parts I am talking about are the Injection elbow (7), the too short nipple (16) and the lower elbow (12).
 

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Aug 30, 2010
80
yahama 25 Hong Kong
If part 16 in your engine is 8-9" long , stay with it . It has the reason .

My 25 original came with the 2.5" part 16, I found the sea water in the exhaust pipe l flow back to the cylinder head causing corrosion in the lower elbow and the cylinder head. It is because the opening of the exhaust pipe at the hull is in a quite high position.
The longer part 16 will hoist up the upper elbow that can prevent this . I got tailor made a longer part 16 from a local workshop . Alternative , make use the Yanmar 2.5", cut into half and weld it back with a extension tube .

Or you have to do something to prevent the water flow back from the exhaust pipe .