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(39)88 Cobra 5.7 Cooling Problem on Muffs-gctid384515

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    (39)88 Cobra 5.7 Cooling Problem on Muffs-gctid384515

    I have an 88 Bayliner 2160 w a 5.7 engine and the original Cobra outdrive. When I put on muffs it isn't pumping water into the engine. The house pressure is 40 pounds min. and the half inch hose run is 100'. With the impeller out I can force water into the suction side of the pump housing by pressing on the muffs with my hands but shouldn't the pump create enough suction to lift the water a foot or so from the intake holes to the pump? I took off the hose on the inboard side of the transom that joins the metal tube from the outdrive to the PS oil cooler. With the muffs on and water flowing from the hose, when I start the engine I get no flow out of the tube. I took off the pump housing, checked the impeller (still fine), bumped the engine to check the shaft (it's turning), then took off the outdrive and ran the garden hose thru the pipe from the outdrive into the boat (no obstruction). If the water pump isn't creating a vacuum where would the air leak be if it weren't the water pump gasket or the rubber seals on the bronze(?) tube between the upper and lower units?

    Grateful for any help here!

    Kevin Killilea

    88 2160

    5.7 Cobra

    #2
    Sailorguy wrote:
    I have an 88 Bayliner 2160 w a 5.7 engine and the original Cobra outdrive. When I put on muffs it isn't pumping water into the engine. The house pressure is 40 pounds min. and the half inch hose run is 100'. With the impeller out I can force water into the suction side of the pump housing by pressing on the muffs with my hands but shouldn't the pump create enough suction to lift the water a foot or so from the intake holes to the pump? I took off the hose on the inboard side of the transom that joins the metal tube from the outdrive to the PS oil cooler. With the muffs on and water flowing from the hose, when I start the engine I get no flow out of the tube. I took off the pump housing, checked the impeller (still fine), bumped the engine to check the shaft (it's turning), then took off the outdrive and ran the garden hose thru the pipe from the outdrive into the boat (no obstruction). If the water pump isn't creating a vacuum where would the air leak be if it weren't the water pump gasket or the rubber seals on the bronze(?) tube between the upper and lower units?

    Grateful for any help here!

    Kevin Killilea

    88 2160

    5.7 Cobra
    Yes. First, if everything is good, I would remove the pump, fill the case with water and reinstall. I get occasional issues with my Cobra's where they will not sufficiently prime unless I rev the engine a bit, then they start sucking as they should. Even with new impellers/pump parts/etc. they occasionally do this after sitting for a while.

    With the muffs on, do you see water coming out the little piss hole on the starboard side of the drive?

    Remove the small hose that's connected to the pump housing and see if with the muffs on, water comes out there as well. I believe that hose is used to "assist" the Cobra in priming.

    Comment


      #3
      There is an oddly-shaped rubber sealing ring between the paper gasket and the gimbal mount that seals the water intake from the lower unit into the transom assy through the gimbal. Is that intact? A new one always comes as part of that gasket set, along with a paper gasket and two o-rings for the driveshaft. I've never had to "prime" mine.

      Comment


        #4
        Have you tried a new impeller? I know you say yours is still good, but they can be tricky. I thought mine was "still good" this year during my summerization, until I looked really close inside where the shaft seats and noticed that the plastic was cracked. The shaft wouldn't have done a good job at spinning the impeller, as the plastic shoe it fits into would have just bulged and allowed the shaft to spin inside it. $8 for a new impeller is a cheap thing to try...

        What about the water pump housing? The metal cage has slits in it...is it possible it slipped somehow and those slits don't line up where they should any more?

        Comment


          #5
          I HAVE HAD TROUBLE TRYING TO DRAW WATER UP ON MUFFS.THE SOLUTION, THERE

          WAS A SMALL PINHOLE LEAK IN THE STERNDRIVE RIGHT IN THE AREA OF THE PICKUP

          STRAINER.IT WAS KILLING THE SUCTION.LOOK REAL CLOSE. IT CAN EASILY BE

          FILLED WITH JB WELD OR SOMETHING SIMILAR.HOPE THAT HELPS.:coo-

          Comment


            #6
            mainecoast wrote:
            There is an oddly-shaped rubber sealing ring between the paper gasket and the gimbal mount that seals the water intake from the lower unit into the transom assy through the gimbal. Is that intact? A new one always comes as part of that gasket set, along with a paper gasket and two o-rings for the driveshaft. I've never had to "prime" mine.
            Where are you getting your kit from? I ordered this kit to get mine done, but it doesn't say anything about the two o-rings, or the "oddly-shaped rubber sealing ring."

            http://shop.tungstenmarine.com/Compr...ing-TM3348.htm

            Since I am a few hours from my boat, I'd like to have everything I need when I get there to do the repair. Thanks.

            Comment


              #7
              jmg-in-alask wrote:
              Where are you getting your kit from? I ordered this kit to get mine done, but it doesn't say anything about the two o-rings, or the "oddly-shaped rubber sealing ring."

              http://shop.tungstenmarine.com/Compr...ing-TM3348.htm

              Since I am a few hours from my boat, I'd like to have everything I need when I get there to do the repair. Thanks.
              Thats the complete pump kit. Good! I was talking about the seal between the drive and the gimbal mount. There is a paper gasket and a rubber one shaped like a small "d" that goes around the water intake on the gimbal mount, the large paper one over it, and then the drive bolted down on top of them. Is that rubber gasket intact?

              Comment


                #8
                Placing those muffs is not an exact science. I have the 7.4 engine with the Cobra outdrive. If those muffs are not perfectly placed, it doesn't take in hose water. Off a fraction, no water. The muffs may look as if they could not be more perfectly placed, completely covering the intakes, however you have to climb off the boat while the engine is running and make sure discharge water is coming out.

                Put the muffs on, turn your water hose on and start the engine. Once it's running, get off the boat and take a look at the outdrive. You should see the engine discharge water splashing randomly out the bottom front of the outdrive. If it's not splashing out of the bottom front area, try moving the muffs slightly on each side intake while it's running, always completely covering the intakes until water is splashing out of the bottom front. You may have to make several adjustments. Once you see that the discharge water is properly coming out, turn the hose up full blast. The engine must be running for it to circulate and the hose must be on full blast or it will not cool. I have lots of water pressure, muffs still have to be perfectly placed and the hose has to be on full blast.

                It can be done, you just have to screw with the muffs until you find the right placement. Finding the correct placement takes some patience.

                Comment


                  #9
                  My apologies for the lapse in answering your replies to my initial post. Just after I posted, I had to get a tune up myself, and am glad that I'm now ready to resume my boat related issues.

                  So now back to the problem. When on the muffs at home, the water pump on my Cobra outdrive will not pull the water from the muffs to the pump, a distance of 15 inches (without figuring in how high the water rises in the outdrive due to the pressure of the water). The sequence is: 1. Turn on the water (40 lbs pressure), 2. Start the engine, 3. Sqeeze the muffs hard on both sides to better seal them and force the water into the pump, 4. The engine changes pitch slightly as the pump begins working to push the water thru the cooling system, and 5. A few seconds later the water from the engine (really the manifolds/risers) begins flowing out the outdrive at a good rate.

                  Some of the things I've done:

                  Tried other muffs to see if they sealed better

                  Replaced the impeller

                  Replaced the whole housing assembly (gasket, O ring, friction plate)

                  Replaced the "water pump adaptor" plate with shaft seal

                  Pulled the outdrive to look for corrosion holes in the case that might have compromised the suction

                  So my question is, what could keep the pump from creating enough suction to prime itself, and where to look?

                  Thanks for all prior responses!

                  Kevin

                  Comment


                    #10
                    You are saying you have replaced the impreller in the drive - correct? At the back if the drive water pump housing is a barbed fitting. This attaches to a plastic (or rubber) line that trails off somewhere (probably the side pee outlet). This line would vent the pump housing so that it will fill quickly and prime with water from your muffs. Is that line plugged?

                    Comment


                      #11
                      submerge the drive past the water pump in a tub see if it pulls water then.
                      Be good, be happy, for tomorrow is promised to no man !

                      1994 2452, 5.0l, Alpha gen. 2 drive. Sold ! Sold ! Sold !

                      '86 / 19' Citation cuddy, Merc. 3.0L / 140 hp 86' , stringer drive. Sold ! Sold ! Sold !

                      Manalapan N.J

                      Comment


                        #12
                        I switched outdrives from Cobra to Cobra SX thus having to install an engine mounted water pump. On initial start up I had trouble getting the pump to pick up suction. My muffs had round cups and were fed to one side. I found a set that had rectangle cups and a "Y" so that both sides were fed and have had no other problems.

                        Comment


                          #13
                          Yep. The impeller's good. Checked to make sure it's turning. SS cage with the slits is in correct orientation. Light grease on the impeller. Blew thru the barbed fitting before putting the housing on. All clear. And so is the thin tube that goes over the barb and down thru a hole into a cavity in the upper sterndrive.

                          I've tried readjusting the muffs and changing them to see if I can get a better seal, but the only thing that works is to sqeeze them really hard to force the water all the way up to the pump. I'm just not getting any suction, so I think there must be an air leak somewhere!

                          Comment


                            #14
                            Talon The muffs I'm using are the rectangular ones fed to both sides. Got them at West Marine here in Lauderdale. Bent the U shaped rod a little more to give it a tighter fit. I said in an earlier post that the pressure was 40 lbs. That's the min. My house has a well and the pressure switch is a 40/60, so the pressure is always somewhere in between. Still no beans.

                            Chief I'll give it the submersion test if I can find the right sized tub/container somewhere in my shed. Just curious......I haven't used the boat that often since I bought it, but when it's floating on it's lines in the water isn't the water pump either submerged, or almost so? Seems when I look over the stern I just see the top of the outdrive, or maybe a few inches above.

                            Thank you both for your suggestions

                            Comment


                              #15
                              Very weird, because I have never had an issue getting water to my system with the old school one sided muffs. Weird also that water pressure won't feed it alone, but a squeze on the muffs would?? That squeeze can't amount to much compared to the water pressue.

                              How about this: Try to put some water (just a little pressure) into the suction side of the pump after removing the impeller. You might need some rubber or foam to get the hose semi sealed to the pump inlet,. It should only pour out through the water intake screens. Then use your muffs to block the intake holes (and block the hose line to the muffs) and see if water is pouring out somewhere else. If you have water pouring out all over, then the seals on the water tube between the drive halves are toast. You could easily crack the drive and fix this.

                              Comment

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