When we bought our 2007 Hunter 41AC (with a Yanmar 4JH4E) about 2-1/2 years ago, the surveyor's report had a list of items that needed to be addressed. I took care of the ones noted as urgent a long time ago but I finally finished today the last one noted as non-urgent - replacing the fuel lines between the tank and engine and on the engine itself. The surveyor's comment indicated that the hoses that were swollen or cracking should be replaced but I opted to just replace all of them.
Most of the lines were either 5/16" ID or 8 mm ID and I opted to replace all of those with 5/16" ID since it was more readily available and 5/16 is just a few thousandths smaller than 8 mm. However, the injector return hoses were 5 mm ID so I sourced some 3mm hose even though I probably could have used 3/16".
I was suprised to see that the cost of the S shaped hoses between the injectors (Yanmar p/n 129270-59550) were about $35 each so I decided to see if I could successfully form some of the 5mm hose to suit. For this purpose I built a jig to hold the hose in the desired shape. After heating the hose with a heat gun it became more pliable and was easily pressed into the jig. After the hose cooled down, it held its shape well enough to allow it to be installed on the engine.
The first photo shows the jig with the old hose inserted while the second shows a new section of hose inserted for forming. The two black magic marker lines on the rectangular pieces indicate where to mark the hose for the final cutting to length.
The third image is a sketch showing the important dimensions of the jig components.
Most of the lines were either 5/16" ID or 8 mm ID and I opted to replace all of those with 5/16" ID since it was more readily available and 5/16 is just a few thousandths smaller than 8 mm. However, the injector return hoses were 5 mm ID so I sourced some 3mm hose even though I probably could have used 3/16".
I was suprised to see that the cost of the S shaped hoses between the injectors (Yanmar p/n 129270-59550) were about $35 each so I decided to see if I could successfully form some of the 5mm hose to suit. For this purpose I built a jig to hold the hose in the desired shape. After heating the hose with a heat gun it became more pliable and was easily pressed into the jig. After the hose cooled down, it held its shape well enough to allow it to be installed on the engine.
The first photo shows the jig with the old hose inserted while the second shows a new section of hose inserted for forming. The two black magic marker lines on the rectangular pieces indicate where to mark the hose for the final cutting to length.
The third image is a sketch showing the important dimensions of the jig components.
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