I have a Larsen 1998, with a 4.3 Volvo 190hp carborated. When it was winterized last fall the drain plug on the intake manifold was missed, and I'll assume it is cracked. <br /><br />I didnt catch the forgotten plug when I installed the other plugs so I put it in the water late Friday just before dark. First I let it idle but when I ran it at full throttle it would cut out and the motor was covered with a milky brown oil/water sludge mix, the dipstick was covered to the top with the same stuff. <br /><br />I bought several 5qt jugs of oil $4.87 and three $2.00 oil filters at Wal-Mart figuring it best to get that sludge out of there ASAP. <br /><br />First I pulled the belt off the water pump. Then I tried to suck the sludge out through the dipstick - but it was thicker than honey so I had to drain it into the bilge through the oil pan drain plug. After a couple hours of slow draining I changed the oil and filter and started it up and ran it at high idle until the gauge indicated 200 degrees (about 5-7 minutes). <br /><br />I repeated this two more times and each time the oil got better - the third time it came out like off color milk and was very runny. <br /><br />Finally got to bed at 6:00 am and here it is before 11 and I am getting started on it again<br /><br />I think I'll change the oil a couple more times to see if the oil gets more normal. Then I get to look forward to the tear down for the Intake manifold - any one have a good source on one?<br /><br />What damage might I have done to the engine other than the Manifold crack, and what other things might I do to try to save the engine? <br /><br />The dipstick indicated the engine was full to the top of the sludge, I wonder if I should way overfill the oil too or maybe fill it up with diesel because that sludge is stuck to everything when I look through the oil fill cap. But it is getting better.<br /><br />Thanks for your help.<br />Steve in Iowa