Ok, this might seem a bit wierd, but after posting the original note in June, my Yanmar 4JH3-HTE low pressure lift/priming pump started to leak fuel (it was visible on top of the fuel filter) just recently. It has 2,980 hours and in the Mac Boring Diesel Engine Class I took they recommended you change it at 2,500 hours.
It was a simple swap for a new part that cost about $60. I didn't know Yanmar made any parts for less than a couple hundred!
