Welcome Guest - Sign Up today
Welcome Guest - Sign Up today
Store Links Mobile - Shop Now

Announcement

Collapse

Help Tip: If you have a question that has not been answered to your satisfaction in the archives, it is always best to start a new thread of your own. By starting your own thread, you will receive the maximum number of views by forum members.

Below are some additional forum policies in hopes of all iboats members will follow, Thank you.

1. Please do not reply to old topics or hijack existing topics. Old topics of a technical nature are like a library book, Please do not write in them.

2. Old topics should be considered archives and used for reference only. Please do not reply to them.

3. Do not take over someone elseís topic (aka hijack) with your own question, even if it is similar. If you have a question that has not been covered to your satisfaction in the archives, it is always best to start a new topic of your own.

4. If you have a question for the original poster (OP) and the topic is over 30 days old, send the OP a PM, he may not even visit the forums any longer, or may not notice your question in the old topic.

5. By starting your own topic, you will receive the maximum number of views by forum helpers that may not even notice your question when itís posted at the end of someone elseís topic. And those answers will be specific to your particular issue.

6. Please do not post to topics that have been inactive for more than 3 months unless you are the original poster. We have very active forums and any topic that remains inactive for that long should be considered "dead". It is especially confusing when there is an entirely new question posted to an old topic.

7. Posting at the end of any topic is considered to be hijacking the original posters topic which in turn subjects the topic to be closed if it continues to happen thus not making it fair to the original poster in the future had for some reason he/she needed to return for additional information or provide an update of the problem solved which is always welcomed within a reasonable amount of time frame.

8. Please note that you should see a red banner pop up near the bottom of each inactive topic asking you not to reply to old topics. The Red banner will read: Please note this topic has been inactive for 90 days. For the best results, please start a new topic.

Thank you all in advance for doing your part in helping iboats run a smooth ship.

Additional forum rules linked below.
http://forums.iboats.com/forum-rules-guidelines-405/
See more
See less

Volvo Penta 5.7GL runs bad?

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Volvo Penta 5.7GL runs bad?

    I recently bought a Wellcraft Excel with a Volvo Penta 5.7GL.

    Have problem with the engine, feels like itís misfiring or donít get enough fuel when Iím trying to get the boat up to plane. Lack of power and running uneven . I changed the spark plugs because they were black, with lots of carbon build up. But it didnít help, and the new plugs go black right away.

    I have cleaned the distributor cap because there was some oxide there, but no difference. I also checked that I had sparks on all the plugs.

    And I think there is a bit too much smoke coming from the engine on idle.

    Where should I start?

  • #2
    start with the basics
    check compression
    verify contents of fuel filter
    make sure the clear hose from the fuel filter does not have fuel in it
    clean/rebuild the carburetor
    1988 Cruisers Rogue 2420 -VP 290 DP now powered by custom 468 - http://forums.iboats.com/forum/owner...988-rogue-2420

    Past Boats
    1970 Wooster Hellion - Merc 9.8
    2002 SeaRay 190BR - 5.0 - A1G2 - "Cheasheads in Paradise"
    1984 Avanti 170DLI -3.0 stringer- "Ship Happens"

    What’s behind you doesn’t matter.Enzo Ferrari

    Comment


    • #3
      What's the deal with the clear hose from the fuel filter? What is it for, if not for fuel?
      Guess I'll start on the fuel side...

      Comment


      • #4
        its a tell-tale vent hose if your fuel pump fails, that hose fills up and the excess fuel is pushed into the carburetor and it runs really rich forcing someone to take a look.

        without that line, the excess fuel would be dumped into the bilge........


        ..........boom

        1988 Cruisers Rogue 2420 -VP 290 DP now powered by custom 468 - http://forums.iboats.com/forum/owner...988-rogue-2420

        Past Boats
        1970 Wooster Hellion - Merc 9.8
        2002 SeaRay 190BR - 5.0 - A1G2 - "Cheasheads in Paradise"
        1984 Avanti 170DLI -3.0 stringer- "Ship Happens"

        What’s behind you doesn’t matter.Enzo Ferrari

        Comment


        • #5
          Ricky_rich regarding "clear hose from the fuel filter" hopefully you meant Fuel Pump?
          _

          Comment


          • #6
            This is how my plugs look after just being run for 30 minutes. Engine running rich? The fuel filter is also new.
            I have to check that hose next time I'm at the boat. But if pump is pushing gas into it, does that mean that the ordinary fuel line is blocked?

            Comment


            • #7
              No it means the fuel pump diaphragm has a leak. Instead of dripping into the bilge, the leaking fuel is routed to the carb where it is burned and makes the engine run lousy making you want to fix it. One of the reasons Marine parts(carbs, fuel pumps, starters, alternators, and others) are different than auto parts

              Comment


              • #8
                Those plugs have had a "rich" life, too much fuel and not enough air I would say.

                Is it hard to start? Do you need to have the throttle open past 1/3 to get it to start? Because it sounds like the carb is flooding, and if it is a Holley then it could be the internal power valve has ruptured. If that happens then fuel goes nearly unfettered from the fuel bowl into the intake manifold plenum.
                _

                Comment


                • #9
                  Engine is a bit hard to start when cold, but when it's warm it's no problem. I have a two barrel Holley carb.
                  Yesterday I checked that I didn't have and fuel leaking from pump to carb through that hose.
                  I also run the engine from a separate tank with fresh fuel, in case I had water in the big tank.
                  Changed distributor cap and rotor.
                  None of these tings made any difference. Engine runs a bit uneven on idle, and feels like I loose a cylinder or two from time to time when giving throttle? I'm really lost here..

                  Comment


                  • #10
                    Ayuh,.... You've got a Carb problem,.....

                    Rebuild the Carb,....

                    Changin' ignition parts does nothin' for the induction system,....

                    Comment


                    • #11
                      Carb rebuilt kit ordered, I'll get back to you with the result when the job is done.

                      Comment


                      • #12
                        Back here again now. Have rebuilt the carb with a new power walve, needle valve and gaskets and so on. Put it back in the boat today but made no difference against before. Also changed the fuel filter today, but no difference. Tried to make a few videos when engine is running. Maybe sounds better on the video than in reality. But listen closely; you hear how I lose a cylinder from time to time. And with engine lid closed, I can hear a kind of BOOFF sound from time to time. Hard to explain...
                         

                        Comment


                        • #13
                          Video with closed engine lid, more obviosly when egine missfire
                           

                          Comment


                          • #14
                            Sounds like it is laboring. Maybe a vacuum leak. When the motor box is closed it sounds like it is gasping for air. Is the motor box vented? If so are the vents clear?
                            US Submarine Force Veteran
                            USS Corporal SS346

                            Comment


                            • #15
                              Sign up today
                              Running the engine without airfilter and open lid, still runs bad. So I don't believe there is lack of air. Get a feeling that I'm loosing a cylinder... Some vibration when the engine runs bad.
                              Did a compression test, and here are the result.

                              1. 10.5 bar
                              2. 10.5 bar
                              3. 9.0 bar
                              4. 10.5 bar
                              5. 10.5 bar
                              6. 8.5 bar
                              7. 9.0 bar
                              8. 10.0 bar

                              I also tried new sparkplug cables, but made no difference.

                              Comment

                              Working...
                              X