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Mercruiser 4.3LX Seems Excessively Loud

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  • Mercruiser 4.3LX Seems Excessively Loud

    Winterized the motor properly. Just replaced all fluids and filters. I live on a lake so started it in the water. Boat started right up, and ran well, but seems excessively loud - to what I think I remembered. Kind of between a squeal/excessive vibration/growl. I have searched the site to try and locate possible causes. Not sure what is causing it. Based upon my minimal motor experience, I initially thought bearings. I tried the hose "stethoscope" test to see if it seemed like the power steering pump or alternator, but I believe its coming from the rear of the motor. Can the steering actuator make this noise? I do think the steering was stiffer than normal. I had a slight power steering fluid leak last year. It was a loose non pressure hose. I noticed what may be a little fluid on the pressurized hose connection. Not sure if that was there before or not. Also, can the gimble bearings make noise when in neutral? Thanks in advance for advice.

  • #2
    As long as the motor is running, everything from the coupler down to the pinion gear in the lower unit is turning. So the answer is yes, including the gimbal bearing.
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    • #3
      Remove the drive jam a water hose in the bell housing water port where water comes up from the drive, an old washing machine hose cut in half works well. Start the engine if noise is gone it’s in the drive , gimbal bearing or u joints. Likely water was in the bellows and bearing or ujoint rusts over winter.

      was drive oil changed at end of season?

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      • #4
        Drive oil was changed this week. Not at the end of the season.
        If the noise is gone with the drive out, then what's next? Thanks much.

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        • #5
          Didn't say what year the motor is... If its b-belts, I would remove the vbelt that runs to the power steering pump since you alluded to that being a potential issue...

          If its a serpentine belt, then remove it and listen for the noise... If its gone, then you know its either the alternator or powersteering pump

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          • #6
            Took the belts off. Wasn't the motors... Took the out drive off and yes - there was water in the bellows and some rust. So, evidently it wasn't appropriately winterized. The gimble bearing seems ok. Got it cleaned up pretty well. Now what? Thanks for the help.

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            • #7
              Need to run it without the drive on, and see if you still hear the noise or not. If not, then it's either in the drive, or the gimbal bearing.

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              • #8
                Originally posted by FBCoach View Post
                Took the belts off. Wasn't the motors... Took the out drive off and yes - there was water in the bellows and some rust. So, evidently it wasn't appropriately winterized. The gimble bearing seems ok. Got it cleaned up pretty well. Now what? Thanks for the help.
                Now you find out what is FUBAR'd in the drive because it wasnt serviced prior to winter.
                Cheesehead boating the Gulf Coast of FLA 27.51° N, 82.53° W

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

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

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

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                • #9
                  If you found water in the bellows and rust, odds are your going to need a new gimbal bearing and u-joints at a minimum.

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                  • #10
                    Originally posted by Mad Props View Post
                    If you found water in the bellows and rust, odds are your going to need a new gimbal bearing and u-joints at a minimum.
                    Assume when running it with drive off it was quiet? What’s next ? As pointed out above. What did drive oil look like ? If any milky or metal take cap of drive. If oil was clean do the gimbal and joints . They are not much if u can do it your self . Worth pressure testing the drive while it’s off.

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                    • #11
                      Originally posted by FBCoach View Post
                      .... The gimble bearing seems ok. Got it cleaned up pretty well. Now what? Thanks for the help.
                      The gimbal bearing might seem ok, but it's not. A few months from now, it's be noisy, if it lasts that long. You currently have the drive off, pull the gimbal bearing and put a new one in.

                      You're also going to need new unis. I see a lot of people just pumping grease in and the water comes out and they say, "they seem ok". They are most definitely not. Any water in the unis and/or gimbal bearing IMMEDIATELY condemn them. Any water in the bellows basically condemns them.

                      Also you need to examine the seal surface on the yoke. It's likely starting to rust and will eat the seal very quickly. If it were mine, that assembly would be pulled apart NOW, and the surface would have a stainless speedi-sleeve fitted. And since the drive shift housing was pulled apart that far, I'd be fully resealing it.... You didn't give us a serial number, or even a year , but I suspect the drive has been in service for a while now (the last year Merc released a 4.3 as an 'LX' was 1997), and a reseal wouldn't be a bad thing.

                      But, you know, this is just my opinion....

                      Chris.......
                      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
                      The world takes on a whole new perspective when viewed from 100’ below.
                      1972 Bertram ‘Bahia Mar’ 20
                      2006 Mercruiser 4.3MPI (0W617679) w/Alpha One Gen II (0W829301)
                      (Original - 1972 '165' In-line 6. Previous - 1994 4.3LX)


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                      • #12
                        Sorry about the info. Got the boat two years ago from my uncle. It had been sitting for 5 years. With hekp from you guys I rebuilt the transom and stringers: https://forums.iboats.com/forum/boat...om-replacement

                        Did a lot of work tuning the motor last year. When I go the boat it had 67 Hours on it. We put 35 on it last summer. ​​​​​​So the motor and drive now has 102 hours on it.
                        I think the motor is a 96. Boat is a 97. Engine Serial number is 0K158135. Drive Number is: 0K068222.

                        Where I am now: the unis are perma sealed. Had minimal rust. Gimble bearing showed no outer rust. Turned smooth. When I added grease through the zerk, not water came out. Only old grease. Did not find any tears in the bellows but there was about 3 table sppons of water in them when I took the outdrive off. The gear oil was not milky when i changed it.

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                        • #13
                          Been looking online for unis, gimbal bearing, bellows, etc. Seen kits from $60 - $250. Any place you specifically recommend ordering from?

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                          • #14
                            Originally posted by FBCoach View Post
                            Been looking online for unis, gimbal bearing, bellows, etc. Seen kits from $60 - $250. Any place you specifically recommend ordering from?
                            Sorry, for bellows and gimbal bearing, I ONLY use Merc genuine. Tried a few others, didn't work so well.

                            Engine and drive are 1997. And you have Vortec heads, be happy....

                            Chris.......
                            xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
                            The world takes on a whole new perspective when viewed from 100’ below.
                            1972 Bertram ‘Bahia Mar’ 20
                            2006 Mercruiser 4.3MPI (0W617679) w/Alpha One Gen II (0W829301)
                            (Original - 1972 '165' In-line 6. Previous - 1994 4.3LX)


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                            • #15
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                              Sorry to ask or if someone has said already, but did you have it running with the drive tilted up ?

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