Engine runs for a couple minutes, stops hard, no fuel flow

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  • pdecker
    Senior Member
    • Jan 2005
    • 70

    Engine runs for a couple minutes, stops hard, no fuel flow

    Folks, this a follow-on to my earlier thread for my problem that I assumed was coil related. I installed a new coil, added a ballast resistor, and had the same problem of a hard shut down after 90 minutes and would not restart. I checked for spark and had plenty. I checked for fuel flow out of the fuel pump (disconnecting the fuel line into the carb) and had NONE. I jumpered out the OPSS, listened for the pump clicking which it did, and still had no fuel flow.

    Yesterday, I installed a brand new MMI Facet electronic fuel pump, like the old one. Instead of running for 90 minutes, it now runs for only two minutes and shuts down hard. Plenty of spark, no fuel flow. Here's what I did to try to isolate the problem, and would like your advice to see what else I can do to fix it.

    I disconnected the fuel line from the water separator to the fuel pump and stuck the suction end into my red dinghy fuel can. The outlet fuel line from the fuel pump runs to a coffee cup. I turned the key on, and the fuel pumped just fine from the fuel can to the coffee cup. I reconnected the pump to carb line. The engine started and ran just fine for several minutes with gas from the fuel can. So, I assume the fuel pump is working fine.

    Next, removed the water separator/fuel filter element and inspected it. It is less than one year old and looked fine visually, and so I put it back.
    I reconnected the line to the water separator and I removed the fuel line from the fuel tank and stuck it in the gas can. Once again, it pumped fuel into the coffee cup. I reconnected the line to the carb. The engine ran fine for several minutes until I turned it off. So, I conclude the water separator / fuel filter is fine.

    Maybe it's the fuel tank vent. I was able to blow air fairly easily into the tank from the external fuel tank vent at the stern of the boat. It looked silly, but there is no apparent blockage. I removed the tank level sender through the big port on top of the tank, and confirmed there is more than half a tank of fairly fresh gas seasoned with a little MMO. I visually confirmed there was no gunk at the bottom of the tank and the screen as the fuel pickup looks clean. I reconnected everything, and it would run for only a couple minutes again and then stop suddenly. I removed the fuel tank cap to see it it is a venting issue and tried it again, and it would not start. Also, no fuel flow into the carb.

    I'm thinking there must be something mostly blocking the fuel between the top fitting of the fuel tank and the fuel pickup at the bottom. How can I check, and how can I remove the blockage if there? The fuel tank is aluminum. A brass elbow is welded to the top connecting the fuel shut-off valve and the barbed fitting for the fuel hose. The water separator / filter is mounted slightly above the level of the fuel tank.

    Phil Decker
    S/V Catmandu
    1982 Catalina 27
  • JOHN COOKSON
    Afourian MVP, Professor Emeritus
    • Nov 2008
    • 3501

    #2
    Betcha It's The OPSS

    Bypass or short across the OPSS to prove or disprove.

    TRUE GRIT

    Comment

    • pdecker
      Senior Member
      • Jan 2005
      • 70

      #3
      The OPSS is bypassed with a jumper cable

      Yes, I jumpered out the OPSS for these tests.

      Comment

      • ndutton
        Afourian MVP
        • May 2009
        • 9777

        #4
        It may sound out there but please try this: put more fuel in the tank, like 2 or 3 more gallons and test.
        Neil
        1977 Catalina 30
        San Pedro, California
        prior boats 1987 Westsail 32, 1970 Catalina 22
        Had my hands in a few others

        Comment

        • JOHN COOKSON
          Afourian MVP, Professor Emeritus
          • Nov 2008
          • 3501

          #5
          Originally posted by pdecker View Post
          I'm thinking there must be something mostly blocking the fuel between the top fitting of the fuel tank and the fuel pickup at the bottom. How can I check, and how can I remove the blockage if there? The fuel tank is aluminum. A brass elbow is welded to the top connecting the fuel shut-off valve and the barbed fitting for the fuel hose.
          Phil Decker
          S/V Catmandu
          1982 Catalina 27

          I have a 1980 Cat27 Hull #4446.
          I've disassembled the outlet fitting and have replaced the outlet tube. It's an easy job. Just have at it. I sealed it with permatex (#2?).While you have it apart it is a good idea to replace the outlet tube with a plastic tube. My outlet tube was copper when I took it apart. Having copper around aluminum makes me nervous. Also I ditched there screen on the bottom of the tube so there won't be any blockage in the tank. The filters can take care of any KRAP that might come through.

          TRUE GRIT

          Comment

          • pdecker
            Senior Member
            • Jan 2005
            • 70

            #6
            I noticed a similar problem with diesels on another site

            Similar problem with similar boats. I think I will inspect the pickup tube and remove that screen.

            Comment

            • dvd
              Senior Member
              • Dec 2008
              • 452

              #7
              Have you ever replaced the fuel tank or is it an original?

              Comment

              • edwardc
                Afourian MVP
                • Aug 2009
                • 2511

                #8
                Originally posted by ndutton View Post
                It may sound out there but please try this: put more fuel in the tank, like 2 or 3 more gallons and test.
                I agree. A pinhole in the pickup tube can cause these symptoms.
                @(^.^)@ Ed
                1977 Pearson P-323 "Dolce Vita"
                with rebuilt Atomic-4

                sigpic

                Comment

                • ndutton
                  Afourian MVP
                  • May 2009
                  • 9777

                  #9
                  Originally posted by edwardc View Post
                  I agree. A pinhole in the pickup tube can cause these symptoms.
                  We've seen it before but not often. This is one of those things that can drive you nutty if it's not eliminated early.

                  By the way, the EWDS would have uncovered the fuel pressure issue instantly.
                  Last edited by ndutton; 08-04-2015, 09:20 AM.
                  Neil
                  1977 Catalina 30
                  San Pedro, California
                  prior boats 1987 Westsail 32, 1970 Catalina 22
                  Had my hands in a few others

                  Comment

                  • hanleyclifford
                    Afourian MVP
                    • Mar 2010
                    • 7004

                    #10
                    Having your filter/separator higher than your fuel tank imposes an extra burden on a fuel pump already tasked with drawing fuel up a tube inside the tank. Easy to see how the pump could lose it's prime dead heading against the needle and seat while using insufficient fuel to keep the flow coming up from the tank should there be the slightest air leak. I recommend you install a fuel pressure gauge right at the carb. If you had a fuel return line to the tank the pump would always be circulating plentiful fuel up the pick up tube.

                    Comment

                    • pdecker
                      Senior Member
                      • Jan 2005
                      • 70

                      #11
                      Found a blocked check valve

                      Yesterday I removed the fuel line valve and pulled the pick-up hose from the tank. To my surprise, there was a check valve connected that I was not aware of. I unscrewed the check valve from the shut-off valve, and tried to blow through it like Popeye the Sailor Man (toot! toot!), and could barely blow any air whatsoever through the check valve. I don't know what pressure the check valve is supposed to release at, but the actual pressure required now is much much more than the 1 - 2 PSI that the Facet electronic fuel pump is rated. I found the pick-up tube, screen, valve, and elbow squeaky clean. I went to McDonald's Hardware Store in Fort Lauderdale and bought a straight connection to replace the check valve. See the photo attached.

                      I don't know why Catalina put a check valve in that system, but I really think it is the cause for my lack of fuel flow. My working theory of why the engine would work for 90 minutes and then shut down is that the pump would heat up (being mounted on the engine), which would somehow cause reduced fuel flow and/or vapor lock due to the shut check valve. I ran the engine for over 80 minutes at the slip, changing the speed every so often. Works great. I think it is fixed. I'll find out this weekend!

                      Phil Decker
                      S/V Catmandu
                      1982 Catalina 27
                      Attached Files

                      Comment

                      • hanleyclifford
                        Afourian MVP
                        • Mar 2010
                        • 7004

                        #12
                        Congrats - it's a miracle that poor little pump is still alive, deadheading against a needle and seat while pulling a vacuum on the other end, and sitting on a hot engine to boot!

                        Comment

                        • BunnyPlanet169
                          Afourian MVP, Professor Emeritus
                          • May 2010
                          • 967

                          #13
                          ABYC and the USCG require an anti-siphon in gas lines if the tank is not entirely below the level of everything else. That's probably why it's there. It can be a check valve, electric, or manual. The check valve was probably the cheapest....
                          Jeff

                          sigpic
                          S/V Bunny Planet
                          1971 Bristol 29 #169

                          Comment

                          • JOHN COOKSON
                            Afourian MVP, Professor Emeritus
                            • Nov 2008
                            • 3501

                            #14
                            Originally posted by hanleyclifford View Post
                            Congrats - it's a miracle that poor little pump is still alive, deadheading against a needle and seat while pulling a vacuum on the other end, and sitting on a hot engine to boot!
                            Time will tell.
                            If there are any more fuel delivery problems the fuel pump would be the first place I'd look.

                            TRUE GRIT

                            Comment

                            • Bingy
                              Senior Member
                              • Sep 2011
                              • 129

                              #15
                              My engine has been running fine except for longer runs.
                              This weekend after almost two hours of running it shut down.This has happened before and I i have replaced vent system, changed gas filter/water separator at tank and secondary small filter at pump. new plugs , condenser , coil .Gas is clean and water free.

                              Yesterday I removed primary filter at tank and only used in line filter at pump.

                              Left marina and motored up river and back at 1900 RPM for well over two hours.
                              Motor ran perfectly and fuel flow was constant.

                              I have a electric fuel pump and was wondering if the two filter systems was too much and was creating the starving for fuel.
                              Comments appreciated.

                              Comment

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