In the 1979 CD 27 I purchased, the fuel return line ran from the
injector directly to the fuel tank. In the process of replacing all
fuel lines, the mechanic I used was told by Yanmar that the proper
configuration was to run the return line back to the fuel filter
(the primary Yanmar fuel filter on the engine).
After running for 30-40 minutes, the YSM-8 stopped. With each
successive bleeding it ran for shorter and shorter periods (3-5
minutes) before stopping. When bled at the top of the fuel filter,
it is clear that the escaping air is under pressure. It has been
suggested that I revert to the old configuration, running the return
line directly to the fuel tank, where the air will vent external to
the system.
Note: I had a compression test done at the time of purchase.
The reading was on the low side of normal, but within normal range.
Query #1: Did the Yanmar rep get it right, or was this advice
relevant to different Yanmar models?
Query #2: If the Yanmar rep was right, it has been preliminary
diagnosed as a faulty injector. What is the downside of operating
in the configuration at time of purchase (fuel return line to fuel
tank)? I'm thinking it will involve sub par performance, but don't
know if it risks damage to other parts.
Your soonest thoughts are invited either on this board or directly to
my E-mail.
rlmeigel@aol.com
Question re: Yanmar diesel YSM8 7 hp, 1 cyl
Moderator: Jim Walsh