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81 model 305 merc lower unit

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  • 81 model 305 merc lower unit

    Im not going to fix this my self but need a little advice.

    I have a 81 sea ray 197 with 225 305 when i bought the boat couple years back the lower unit had like a clacking noise to it not to loud. Guy told me gimbel bearing so i had him change it.

    After that no noise unless u turned all the way hard one way or another, went like that for a season or 2. week before our wedding end of last year ( we rented a 16x80 houseboat to get married on) had a guy change lower unit fluid he found mostly water in it. I talked to him about the clacking noise we couldnt get it to do it atm go figure. He put some green syn oil in it.

    So we was on the lake for a week ran around some etc but noticed boat was taking on some water not real bad and not sure if this is related.
    If we stepped onto the swim deck u could see the green lower unit fluid in the water .

    We dock the houseboat and i fired it up it died a time or 2 then after trying to start 3 4 th time it wouldnt turn the motor over it acted like something was locked up.

    Heard no noises etc when trying to start it. the wheel wants to turn when trying to start . motor seems like its getting atleast one crank and stops prop spins by hand.

    I think the boat may have wrong lower unit i know it was changed at one point. I d like to just have more info and order the parts online and have someone fix it. So if lower unit is bad what would be the one i need.

    Stern drive sn on block 5901722
    Block sn 5923379

    5878013 sn for lower unit now
    Thanks for any help

  • #2
    Re: 81 model 305 merc lower unit

    My guess is the drive is locked up. You can pull it pretty easily and try cranking the engine so see. If it turns out to be a bad drive just get an SEI. It will be cheaper than trying to fix the current drive. Check your bellows. That is probably the cause of the water coming in.
    83 Sunrunner 16.5 120 merc Alpha 1 drive SOLD 8/1/13

    1996 Crownline 202BR
    5.7l EFI 0f791070
    Bravo I drive

    GMC Yukon tow rig

    Comment


    • #3
      Re: 81 model 305 merc lower unit

      It sounds like you have a few problems here. Water leaking into boat is most likely coming in from one of the boots. My guess is they all need to be replaced. Also sounds like you might need a seal kit on your outdrive, if gear oil is leaking out then you have seal damage at minimum. You are most likely looking at outdrive issues locking the motor up. As stated above, you're going to have to pull it off and see. Most outdrives are allergic to water in the oil and do not react well over an extended period of time. If the engine still does not turn over with the drive off then you need to pull the spark plugs and check for water in the cyls.

      Before you spend a dime on parts invest in a service manual. There are a number of special tools required to service an outdrive and they will all be listed in the manual. At some point in time you will need to decide if the boat is worth putting a bunch of new parts into.

      Comment


      • #4
        Re: 81 model 305 merc lower unit

        The only good purpose of a Seloc manual is for a knee pad. Go here and find the factory manual for free.

        Boatinfo - The library, containing manuals, brochures and other technical documents from the last hundred years!
        83 Sunrunner 16.5 120 merc Alpha 1 drive SOLD 8/1/13

        1996 Crownline 202BR
        5.7l EFI 0f791070
        Bravo I drive

        GMC Yukon tow rig

        Comment


        • #5
          Re: 81 model 305 merc lower unit

          Originally posted by bassboy2000 View Post
          Im not going to fix this my self but need a little advice.

          I have a 81 sea ray 197 with 225 305 when i bought the boat couple years back the lower unit had like a clacking noise to it not to loud. Guy told me gimbel bearing so i had him change it.

          After that no noise unless u turned all the way hard one way or another, went like that for a season or 2. week before our wedding end of last year ( we rented a 16x80 houseboat to get married on) had a guy change lower unit fluid he found mostly water in it. I talked to him about the clacking noise we couldnt get it to do it atm go figure. He put some green syn oil in it.

          So we was on the lake for a week ran around some etc but noticed boat was taking on some water not real bad and not sure if this is related.
          If we stepped onto the swim deck u could see the green lower unit fluid in the water .

          We dock the houseboat and i fired it up it died a time or 2 then after trying to start 3 4 th time it wouldnt turn the motor over it acted like something was locked up.

          Heard no noises etc when trying to start it. the wheel wants to turn when trying to start . motor seems like its getting atleast one crank and stops prop spins by hand.

          I think the boat may have wrong lower unit i know it was changed at one point. I d like to just have more info and order the parts online and have someone fix it. So if lower unit is bad what would be the one i need.

          Stern drive sn on block 5901722
          Block sn 5923379

          5878013 sn for lower unit now
          Thanks for any help
          Ayuh,..... Welcome Aboard,.... It sounds like you've got Alota problems goin' on,...
          As noted, pullin' the drive off will let ya know whether the drive, or the motor is seized,...

          Yer "Noise" sounds like the u-joints, but the drive has enough problems, a Whole New aftermarket drive would cover the u-joints,....
          'n the water in the drive,....
          'n if the drive is seized,...

          The water comin' into the boat, could be the Bellows, either the driveshaft, or shift cable bellows,...

          'course, if ya pull the drive, 'n the motor still don't turn, that'll have to be diagnosed to see why,...

          Ya really shouldn't be buyin' Anything but some Mechanic's time, til it's Diagnosed to see exactly what needs replacin',..

          Comment


          • #6
            Re: 81 model 305 merc lower unit

            Originally posted by Bondo View Post
            The water comin' into the boat, could be the Bellows, either the driveshaft, or shift cable bellows,...
            ..
            That's just SOME of the possible areas of course. I would also wonder about the condition of the transom, etc. A lot of evaluating needs to be done before spending any money.

            I am a little confused. You mention a Sea Ray and a house boat. Which are you working on? Or is it one and the same?

            Comment


            • #7
              Re: 81 model 305 merc lower unit

              I was typing all that up on my phone. we was on the houseboat for a week with our runabout in the water with us all week and that's when it all happened.

              The boat is in great shape trans is solid and motor runs strong changed plugs the week of the lower unit oil and the plugs where older with only typical wear on them, no oil. We really like the boat its really wide or at least feels it and rides smooth. I figured i would have them change the boots with the lower unit.

              From what i have seen its about 1200 to 1500 for a new lower unit. The lower unit on it now has a SN on it, but i am not sure that's the right one b/c of that clacking type noise. When i start looking them up i see there is different shaft sizes so i am not sure which one I need.

              Comment


              • #8
                Re: 81 model 305 merc lower unit

                Just pull the drive. It is easy. Put it in forward. Remove the trim rams at the drive and the 6 nuts. Pull it off. It weights around 75 pounds so be ready for it but I used to do it as a one man job all the time. I had it down to a 5 minute on and off.
                83 Sunrunner 16.5 120 merc Alpha 1 drive SOLD 8/1/13

                1996 Crownline 202BR
                5.7l EFI 0f791070
                Bravo I drive

                GMC Yukon tow rig

                Comment


                • #9
                  Re: 81 model 305 merc lower unit

                  Thanks thumpar for the link that helps with me with my pontoon problem . Why do i need to remove the lower unit ? I do not have the time to take on a project like this. If i have to pull it to find out which one i need to order i will.

                  Comment


                  • #10
                    Re: 81 model 305 merc lower unit

                    Originally posted by bassboy2000 View Post
                    From what i have seen its about 1200 to 1500 for a new lower unit.
                    You can buy a new lower unit for $795 from Sterndrive Engineering. Or by "lower unit" do you mean the entire out drive?
                    Last edited by Fishermark; February 28th, 2014, 07:36 PM.

                    Comment


                    • #11
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                      Re: 81 model 305 merc lower unit

                      Originally posted by bassboy2000 View Post
                      Thanks thumpar for the link that helps with me with my pontoon problem . Why do i need to remove the lower unit ? I do not have the time to take on a project like this. If i have to pull it to find out which one i need to order i will.
                      I am not suggesting to remove the lower but the whole drive. At this point you don't know if it is the drive that is locked up for sure. Once you get it off you can test the engine to make sure that is not it. With the drive off you can measure the shaft also. At some point the drive will need to come off in this project so might as well do it now.
                      83 Sunrunner 16.5 120 merc Alpha 1 drive SOLD 8/1/13

                      1996 Crownline 202BR
                      5.7l EFI 0f791070
                      Bravo I drive

                      GMC Yukon tow rig

                      Comment

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