Could be a dirty air filter, or a clogged mixing elbow. Try running after removing the air filter (easiest test). If that's not the problem, remove the mixing elbow and clean it out. If you have an old Yanmar and the mixing elbow has never been removed, that's likely the problem.
Alan Bergen 35 Mk III Thirsty Rose City YC Portland, OR On Tue, Sep 6, 2022 at 8:40 AM Nate Flesness via CnC-List < cnc-list@cnc-list.com> wrote: > So my 42 years new 2QM15 starts normally (a little black smoke), but > *suddenly* she won't hold a throttle setting and wpm wanders down > erratically, sometimes more throttle helps for a few seconds, sometimes > not, then she dies, > > The problem showed up at the same time I realized I had run her very low > on diesel. Have added diesel, checked air cleaner, replaced fuel filter, > done the normal fuel filter bleed, and as I said, she starts fine, but the > problem remains. I pulled the "brillo pad" filter inside the fuel tank > years ago, polished tank and fuel, and have used Biobior every winter since. > > Ideas most welcome! > > Nate > Sarah Jean > C&C 30-1 > St, Croix River > Hudson WI >
