Quick silly question about water in oil.-gctid803896

[aknurse]

Background. 2859 with 7.4 merc mpi. I just had a shop replace my heat exhanger. I ran it on the hose at home up to temp and all was good. I got about 5 miles out of port she started sputtering and I noticed my voltage gauge dropped so I opened the engine hatch and had about 6-8 inches of raw water in my bilge. The belt was really throwing water up all over right towards the air intake. I couldnt tell where water was coming from at the time. I didnt dare shut her down for fear she may not light back off. Made it back under own power and tied off at dock and realized it was a hose to the port exhaust elbow that had come off and was flooding. Now I have milky oil. I was running close to wot when she started running rough like water in fuel. I know at wot theres alot of air getting sucked in. Can enough water get by to get in the crank case? Or do I possibly have another big problem too? The engine never ran over 175 according to the gauge and the antifreeze level stayed static. Ideas?

[canoel]

A few questions.

First, did you check the oil before you left to verify there was no water in the oil? Is this the first outing of the year? Was the boat properly winterized?

It does not take much coolant in the oil to make it milky, so the coolant level can be misleading.

You have a couple choices. Change the oil and filter, repair the hose and take it for a run.

Second choice, full leak test, compression test, leak down etc.

I would go for the first choice. Big block chevrolets are not know for head gasket failures unless it was not properly winterized.

[aknurse]

"canoel" post=803900 wrote:
A few questions.

First, did you check the oil before you left to verify there was no water in the oil? Is this the first outing of the year? Was the boat properly winterized?

It does not take much coolant in the oil to make it milky, so the coolant level can be misleading.

You have a couple choices. Change the oil and filter, repair the hose and take it for a run.

Second choice, full leak test, compression test, leak down etc.

I would go for the first choice. Big block chevrolets are not know for head gasket failures unless it was not properly winterized.

Oil was new and golden still from when I winterized her this last spring. She burns a bit of oil when shes run hard. I already intend to do choice 1. She doesnt seem to want to run now however. She coughs like she wants to when I turn her over. Im going to pull the spark arrestor and plugs today to do some further investigating.

[builderdude]

The engine did not overheat because the closed cooling system was still getting some flow from the raw water pump, however your exhaust on the port side would likely have gotten way to hot and scorched the interior of the rubber couplers and the flapper on that side so check those items. I'd do choice 1 but also pressure test the cooling system.

[ken51k]

"She coughs like she wants to when I turn her over." Check your distributor cap, all that water spraying around you might have water inside the cap.

[canoel]

+1 to all of the above. Your carb most likely sucked in a bunch of water. May take a bit to get it started. Clean the cap and rotor. Clean the flame arrestor. Intake may have trace amounts to moisture too.

[aknurse]

Well after pulling the plugs, shooting some WD40 in each and opening up the intake butterfly and letting it sit for a day to dry out she lit right off.Wen I pulled the spark arrestor a small amount of water came out. I changed the plugs out. Many were caked with salt. I ran 2 new batches of fresh oil through with some Seafoam, getting up to temp and running for about 15 minutes each time changing filters each time. The oil has appears to have little to no water in it now. I'm getting my hands on a coolant pressure tester tomorrow, I'm hoping that I dodged a large bullet this time.

[builderdude]

Glad to hear she's running again. Another thought after having potential water down the intake: run it up to temp again then do a compression test.

[Pcpete]

Your fix was exactly what I was going to tell you to do. Hope there are no new problems.