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  • riser

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Name:	riser.jpg
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ID:	29113 I have had 2 of these risers completely clog. One had 80 hours and the other only 40. Maybe a casting flaw but if you have them, check.
    1988 26' cuddy
    1975 20' open
    16' Sandpiper
    14' Certified Fiberglass

  • #2
    They look like 3" Chevy/ Mercruiser risers which is what I have on my 350. Upgraded to 4" which is my understanding. I have the closed cooling setup. I havent had any issues yet. Give them an acid bath. Maybe its that's NC mud.
    '78 20ft Cuddy
    Mercruiser 350 FWC preVortec w/Carb


    • #3
      So today I winterized which means ingest anti freeze in the raw water circuit for those not in the North. After running on the garden hose to warm things up, I shut down. But before I shut it down, I bleed off thru these petcocks I installed. I wait until I get clean water. I usually get some sludge.

      I also redo this bleeding procedure when I shut down just to bleed any water off. It seems to create a pocket of water that avoids antifreeze when winterizing that I have seen get crusty during a freeze before. I have a closed cooling system which means only the risers and not the exhaust manifolds see raw water. Just what I do.

      Click image for larger version

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ID:	29258 Click image for larger version

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ID:	29259
      '78 20ft Cuddy
      Mercruiser 350 FWC preVortec w/Carb


      • #4
        I have found the wrong thermostat can cause a salt buildup and plug the elbow. No problem with a 142 deg.
        20' PH several modifications'

        17 Irvette IB V8 gm

        26 Ranger Tug diesel