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Mercruiser 4.3 1997 Carb model RAW water cooled. water in oil. HELP

R

rebeatty

New member
Hi, my engine blew out milkshake all over the top of the intake and lots in the bilge. I am trying to diagnose where it likley came from before oepning it up,
  • Engine has never had more than oil and plugs changed over the years.
  • Fresh water only boat.
  • Probably only 120 hrs on it, oil changed each season.
  • I was able to drain out the sump best I could, change filter, add oil and a product to help break down the oil-water, engine runs like a top, powerful and steady, (OUT IOF THE WATER, for like 5 minutes).
  • Ive plugged the two lines to the manifolds (nio sign of oil there)
  • Ive disconnected the line to the water supply and added air to the line.
  • I get air from both valve covers. Perhaps some from the oil check tube and perhaps some from the carb but not really sure at all.
  • I do know no oil went into the water or is in the exhaust manifolds.

So, now what?
Does this sound like an intake manifold leak? Is there more I can check before I take off the intakes? I can pull the risers, they probably need attention as one was always getting a little warmer than the other over the years. The risers are what I would call an older version from 1997.

Any thoughts suggestions or guidance is very much appreciated.

Bob
 
Last edited:
  • Ive disconnected the line to the water supply and added air to the line.
  • I get air from both valve covers. Perhaps some from the oil check tube and perhaps some
cracked intake or cracked block
 
I pulled it, boy there is a lot of corrosion in there. I am scaping away but dont see a hole. So my dillema, do I take a chance, maybe replace the manifold even if I dont find a hole? Its better than heads for sure, its such a precipus for me as I dont want to get into heads. I am too old for that and would rather just dump the whole boat if thats the problem, BUT if its mearly a intake I can certainly do that. Any opinions?
 
You don't need opinions you need wrenches. Take it apart until you find the problem. If it's as bad as you describe it probably needs a new engine.
 
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