Thanks Niel, I'll look at this on my westerbeke. Doug Douglas Mountjoy 1988 C&C LF 39 Mexico at large 1984 Sabre 34 Port Orchard, WA
On Wed, Jun 28, 2023, 17:53 Neil Gallagher via CnC-List < cnc-list@cnc-list.com> wrote: > David, > > This may be a long shot, but on a Universal M3-20B that I installed on a > club launch, and I think all Universals, the fuel pump gets its power under > normal running conditions via an oil pressure switch. When starting the > engine, the glow plug switch energizes the electric fuel pump in addition > to the glow plugs (you can hear it clicking when you press the glow plug > switch), but once the oil pressure rises it closes the oil pressure switch > and keeps the fuel pump running when you let up on the glow plug switch. > Incidentally the reason you hear the pump running after you shut the engine > off is that it takes a few seconds for the oil pressure to drop to the > point where the switch opens. > > I ran in to a problem with that engine when sludge got in to the > connection to the oil pressure switch and kept it from closing properly, > and thus the fuel pump intermittently stopped running and stalled the > engine. Until I found the real problem I put a relay powered by the engine > on/off key switch that powered the fuel pump directly, but when I flushed > the oil switch a few times it cured the problem. > > Not sure how relevant this may be to your issues, but may be of interest. > > Neil Gallagher > Weatherly, 35-1 > Glen Cove, NY > > On 6/27/2023 12:45 PM, David Knecht via CnC-List wrote: > > So I am back to my engine problem hoping someone can help clarify things. > I have had the engine quit several more times, but with no consistency as > to when or why it happens. We were on a cruise recently and used it often > and for long periods going in and out of harbors. Mostly it worked fine > but had it stall several times: start and run for a few minutes, then > stall, restart then stall, restart then stall, then run fine for 20 min or > more. This happened in two separate situations a few days apart but no > stall several other times. In all cases, it has eventually restarted and > ran for extended periods. These intermittent problems are the hardest to > diagnose in my experience. This seems most likely to be a fuel related > issue so now I am trying to fully understand the fuel system. > > I installed a Racor 500 unit last summer with a T-handle vacuum gauge on > top. Fuel goes from the tank, through the shutoff lever to the Racor, then > to the fuel pump, then to the secondary and on to the engine. If I > understand this correctly, the gauge on the Racor unit will measure > restriction in the fuel flow upstream of the gauge, ie the primary (30 µm > in my case). I know the gauge works because if you partially shut off > the fuel lever, you see the gauge gradually increase in vacuum reading. > But it seems that it will not tell you if the secondary is plugged. > > 1. I don’t see how the secondary (10 µm in my case) could be plugged if > the primary is fine but I guess not impossible. My temptation is to > replace the secondary since the primary is not showing any sign of being > plugged (from the gauge), but I don’t see how this could lead to an > infrequent intermittent stall. > 2. Fuel pump problem (loose wire etc.)? You can hear the fuel pump > running when the engine is off and I have never heard it stop or pause. > Can fuel pumps fail like this? Can that lead to an intermittent stall? > 3. Air getting into fuel line- seems possible, but I don’t see how that > can be the cause if the engine runs for an hour continuously once restarted. > > Any ideas welcome! Dave > > S/V Aries > 1990 C&C 34+ > New London, CT > > > > Please show your appreciation for this list and the Photo Album site and help > me pay the associated bills. Make a contribution > at:https://www.paypal.me/stumurray > Thanks for your help. > Stu > > > Please show your appreciation for this list and the Photo Album site and > help me pay the associated bills. Make a contribution at: > https://www.paypal.me/stumurray > Thanks for your help. > Stu
Please show your appreciation for this list and the Photo Album site and help me pay the associated bills. Make a contribution at: https://www.paypal.me/stumurray Thanks for your help. Stu
