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Generator Sea Strainer Cap Won’t Tighten Down

Discussion in 'General Maintenance/Repair Questions' started by Matt@fullcount, Nov 25, 2020.

  1. Matt@fullcount

    Matt@fullcount New Member

    25
    Nov 25, 2020
    1990 Sea Ray 390 Express Cruiser
    2006 mercruisers
    Hi all, we took our sea strainer out for cleaning yesterday and cannot get the cap to tighten down again. We have tried a new o-ring, new wing nuts, etc. Any ideas? Thanks for your help!
     
  2. dwna1a

    dwna1a Well-Known Member PLATINUM Sponsor

    Apr 23, 2012
    James River
    88 Weekender 300 "Seahorse"
    Twins 350
    Make sure the basket is seated in the bottom of the strainer. Pull the basket out and look at the bottom you will understand what I mean then. Sometimes it takes a wiggle to get it to seat
     
    Matt@fullcount likes this.
  3. Matt@fullcount

    Matt@fullcount New Member

    25
    Nov 25, 2020
    1990 Sea Ray 390 Express Cruiser
    2006 mercruisers
    Thanks, we have that working but even with the strainer out, lid won’t clamp down.
     
  4. Matt@fullcount

    Matt@fullcount New Member

    25
    Nov 25, 2020
    1990 Sea Ray 390 Express Cruiser
    2006 mercruisers
    One of the bolts is tapered and we can’t figure out how it was tight before we removed cap. We tried using same wingnuts and then new. So weird!!
     
  5. hughespat57

    hughespat57 Active Member

    221
    Sep 25, 2016
    Rock Hill, SC
    300 Sundancer 1994, trailered tri-axle LoadRite roller
    Mercruiser 5.7 260HP Alpha One Gen II, twin
    Photos?
     
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  6. dwna1a

    dwna1a Well-Known Member PLATINUM Sponsor

    Apr 23, 2012
    James River
    88 Weekender 300 "Seahorse"
    Twins 350
    Agree, some photos would be good
     
    Matt@fullcount likes this.
  7. markrsimon

    markrsimon Active Member

    148
    Sep 1, 2018
    Cleveland, OH
    92 Sea Ray 400 Express
    454 Mercruiser
    1F0D3C46-C1DF-49B6-BDBC-924317389A0F.jpeg
    Do you have the older perko style with cork orings? Another option would be to use RTV sealant to create a new gasket. Clean up the top, place a bead of RTV, smooth with your finger, and let it sit for 24hours. Provides a great rubber-type seal.
     
    Matt@fullcount likes this.
  8. sbw1

    sbw1 Well-Known Member

    Oct 10, 2006
    West Michigan
    This is listed in my signature
    This is listed in my signature
    C3B49088-512B-4AB9-94F5-014A419D1003_sRGB.JPG Does it clamp down if you remove the o rings?
     
    Matt@fullcount likes this.
  9. Matt@fullcount

    Matt@fullcount New Member

    25
    Nov 25, 2020
    1990 Sea Ray 390 Express Cruiser
    2006 mercruisers
    There wasn’t an O-ring when we removed it but owners manual says there should be one. Here are some pictures.
     

    Attached Files:

  10. Matt@fullcount

    Matt@fullcount New Member

    25
    Nov 25, 2020
    1990 Sea Ray 390 Express Cruiser
    2006 mercruisers
    I posted some below. We ended up just rigging up a temporary fix but appreciate any insight. Do you think the tapered bolt in photo is damaged or supposed to be tapered?
     
  11. sbw1

    sbw1 Well-Known Member

    Oct 10, 2006
    West Michigan
    This is listed in my signature
    This is listed in my signature
    C3B49088-512B-4AB9-94F5-014A419D1003_sRGB.JPG
    I believe your issue is the blue thing in the sea chest. I have never seen that type of material in one of these.
     
  12. ZZ13

    ZZ13 Well-Known Member

    Nov 25, 2009
    Lady's Island, SC
    2001 400 Sedan Bridge
    Cummins 450 Diamond
    Bolt threads look possibly worn down. Since it’s the only thing you didn’t replace, I’d evaluate those now. Did you try threading the nut all the way to the bottom of the bolt to test out the grab the whole length? Or big clamp to clamp the lid on. If it still leaks then not the bolt probably
     
    Last edited: Nov 27, 2020
    Chris-380 likes this.
  13. markrsimon

    markrsimon Active Member

    148
    Sep 1, 2018
    Cleveland, OH
    92 Sea Ray 400 Express
    454 Mercruiser
    Given the year of your boat, I can only assume you have an older Perko strainer which came with cork gaskets. They (Perko) states that you must continue to use the cork gaskets with that model. The newer models make use of the rubber gaskets. Some have stated that the rubber works in the older models.

    https://www.perko.com/catalog/underwater_hardware/103/intake_water_strainer/
    *Note: Older model strainers utilizing cork cylinder gaskets must order 99M Cork Gasket Kit and newer model strainers must order 99R Rubber Gasket Kit.

    A set of new cork gaskets will run you $20-$30, with the hardest challenge finding out what # Perko you have, and ensuring that your getting the right gasket set. You can get just the lid gasket 99N (set of 2), or the entire set 99M which includes the lid, as well as gaskets for the top and bottom of the clear cylinder.

    Looking at your first picture - is the o-ring installed on the cap, or is that old cork? Either way - there is not enough stuff there to create a good seal.

    cork_gaskets.JPG rubber_gasket.JPG
     
  14. brewster16

    brewster16 Active Member SILVER Sponsor

    645
    Aug 9, 2009
    Long Beach Island, N.J.
    '07 44 Sundancer
    Twin Cummins QSC 8.3
    The bolt also looks sketchy....worn down. Is the wing nut(s) slipping on it?
     
  15. hughespat57

    hughespat57 Active Member

    221
    Sep 25, 2016
    Rock Hill, SC
    300 Sundancer 1994, trailered tri-axle LoadRite roller
    Mercruiser 5.7 260HP Alpha One Gen II, twin
    What you call a tapered bolt looks like it was originally a larger diameter thread.
    It may have been re-threaded for a smaller wing nut that can’t go all ghe way to the bottom
    That plus the missing gasket
     
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  16. Matt@fullcount

    Matt@fullcount New Member

    25
    Nov 25, 2020
    1990 Sea Ray 390 Express Cruiser
    2006 mercruisers
    Thanks! I think I’m going to order the replacement cork gasket/o-ring and a new bolt for that side. I can’t find a wing nut that is the correct size.
     
  17. Soulshine

    Soulshine Well-Known Member

    707
    Sep 25, 2016
    Seneca Lake, NY
    '83 SRV 360 Express
    Twin Merc. 454
    I have these same strainers and had the same issue with what you’re calling that tapered bolt.

    It’s actually flattened on 2 opposing sides and as a result there’s reduced thread area. Yours is stripped to the point that the wing nut thread can’t get or maintain a hold.

    You can probably get replacements but they’ll have that same design flaw.

    I replaced 2 of mine with brass threaded rod with flats filed only at the bottom where they’re needed to fit into the housing where they pivot. I cross drilled them for stainless machine screws and Nylock nuts.

    Also, you need the cork gasket. I glued the cork into the recess in the lid with RTV and greased the sealing surface with silicone grease so the cork doesn’t stick to the rim of the bronze housing.
     
    Matt@fullcount likes this.
  18. Matt@fullcount

    Matt@fullcount New Member

    25
    Nov 25, 2020
    1990 Sea Ray 390 Express Cruiser
    2006 mercruisers
    thank you so much! That is really helpful! I appreciate all of the responses. This boat is new to us (May 2020) so we are just getting to know her!
     
  19. Soulshine

    Soulshine Well-Known Member

    707
    Sep 25, 2016
    Seneca Lake, NY
    '83 SRV 360 Express
    Twin Merc. 454
    In looking at your pic again I see that your particular part is not flattened on 2 sides since it’s the smaller strainer. I have that size for my AC but larger ones for my raw water cooling intakes. Those are 3/8 16 NC and have the flats and are where I had this problem.

    You should still be able to fabricate a new one out of threaded rod though and it’ll be simpler to do without the need for the flats.

    Odds are good that your larger ones are as I described.
     
    Matt@fullcount likes this.
  20. ttmott

    ttmott PhD in OCD

    Apr 3, 2012
    Space Coast Florida
    2006 52 Sedan Bridge
    Cummins QSM11
    bbwhitejr likes this.

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