Seems to be the week for Dave’s and diesel fuel problems. Here is my story to hopefully get the wisdom of the group.
Last Wednesday I was out for a lovely sail (7.5-8 knot reach across Fisher’s Island sound for lunch and back). I had motored into the harbor on the other side of the sound for about 15 minutes and then back out again and no problems. I got back to the
mooring area and the engine started and then quit. Tried a few times and it would only come close to starting if I gave it lots of throttle, but would still quit. Sailed to the mooring (which I hit on the first try under sail single handed in 15+ knots of
wind- I impressed myself) put away sails etc. and then tried the engine again and it started and ran fine. I chalked it up to bad karma and went home. Saturday, we sailed to Mystic and motored for an hour into the harbor to the Seaport with no problems.
Today we motored back out and after a long wait for the bridge to open (so about 30 min total motoring) the engine quit again and would not start. A few times before it quit for good, it would suddenly decrease revs for a second and then back up. Fortunately,
the wind direction allowed us to sail out of the harbor and back to the mooring where it would not start.
Then I started taking things apart to diagnose. (Universal M4-30, electric fuel pump)
1. Thought first my fuel gauge (reading half full tank) was mistaken or I had bad fuel. Pulled the probe into the fuel tank and with a flashlight was able to see that the tank was half full and the fuel looked perfectly clean.
2. Took the Racor lid off and found that the bowl was not full. It was about 1-2” down so at about the level of the top of the primary filter. Obviously not good. This triggered the thought that the sound the electric fuel pump had been making was
not what I remembered. Instead of a rapid continuous clicking, it was more irregular and perhaps not as loud.
So I am thinking either bad fuel pump or bad power connection from the key switch to the fuel pump. Does a dying fuel pump work one day and not the next? The other possibility seems to be a small hole/crack in the fuel line so the pump can’t draw enough
vacuum to pull fuel from the tank. Not sure how to diagnose that and seems even less likely to allow the engine to work intermittently.
Solutions/more diagnosis
1. Should I just buy a replacement fuel pump and see if it solves the problem? This is not inexpensive, but not a huge amount of money and a fairly easy test. Universal pump was about $230 from Toad’s Marine, but I seem to remember people on the list
talking about automotive sources that might be cheaper?
2. Does one rebuild a fuel pump or buy a new one?
3. Is there a good way to distinguish power issues from mechanical issues other than a new pump? A friend suggested filling the Racor bowl with fuel, then turning on the pump and see if it draws the level down. The only problem with this is I don’t know
how fast it normally pulls fuel so not sure how to tell if it was pumping, but not fast enough.
Any thoughts welcome. Home now, but plan to go down on Wednesday and work on fixing the problem.
Thanks- Dave
S/V Aries
1990 C&C 34+
New London, CT
