I have a 1998 Yanmar
4JH2E, although I believe my issue crosses many models. I have been suffering for a year now with air leaks
in the fuel
Early on, I replaced the line between the lift pump
and the injector pump
with clear fuel
rated tubing. This allows me to see air bubbles.
I have chased many perspective areas. All unsuccessful.
Recently, I noticed that when I run the auxiliary electric fuel pump
, I have leakage at the engine lift pump
. I removed the suction side line, cut off half an inch, and reinstalled it. No change.
So yesterday, I moved the suction side line from the engine
lift pump directly to the injector pump
, and I now use the electric pump
as my primary engine pump. The engine runs like a champ!
To me, it seems I have a failure in the lift pump. It is not easy to see, will not be easy to remove, and since we are on an extended cruise
, I can't take the engine out of service
while I inspect, and order parts
Has anyone ever had problems with these pumps? Is replacing the pump a likely solution? Is there something that tends to fail that can be replaced? In other words, does anyone have any wise insight into the Yanmar