water leak test gone wrong

[johnbell47]

I have 7 hours on my mercruiser inboard, converted from a 898 merc, 305, newer center rise manifolds, E bay items. I had absolutely no trouble with the engine. I was taking on a little water in the boat and could not detect any from the rudder packing or shaft packing, so I really am sure it is not a hull issue. So, I figgered that the engine had a little leak, putting water in the hull. (this was about 10 gallons in 4 hours, or just enough for the bilge pump to pick up. ) I capped the exhaust thru hulls with rubber test caps and then pressured up the system on the water hose, which is about 65 psi. I had checked the oil before start and was about 1/2 quart low. Long story short, the engine is now full of water. Coming out the valve covers..I think I know what happend but want educated opinions.. Thanks in advance.

 

[Big Boat Bay Buster]

Re: water leak test gone wrong

Hopefully, this just happened----GET THE WATER OUT OF THE ENGINE ASAP!!!! You forced water into the exhaust--it went past the open exhaust valves and into the engine. If you want to leak test the manifolds, you need to remove them from the engine.

 

[Bondo]

Re: water leak test gone wrong

Ayuh,... I hope it's freshwater,+ you're removing it as I type....

The Exhaust Plugs, are where ya went Wrong,....
The 65psi in a 15psi sytem didn't help either...

Ya gotta get it Drained,+ reoiled,.... Now.....

 

[bigskiohio]

Re: water leak test gone wrong

probably blew out your pump seals too.

 

[Don S]

Re: water leak test gone wrong

This is what happens when you don't know how a system works, and you come up with your own personal idea of how to test something you know nothing about.

Probably never occured to you to have someone else drive the boat, remove the engine cover and other access covers over the stuffing box and exhaust system and actually watch to see where the water comes from.

 

[ni7irs]

Re: water leak test gone wrong

Quick get the rope. Someone made a mistake.

 

[fishrdan]

Re: water leak test gone wrong

Here's what I would do...

- Drain oil/water from engine
- replace oil filter and oil
- remove all the spark plugs
- with spark plugs out, turn over engine by hand a couple revolutions to get most of the water out of cylinders, then crank it over with the starter to blow the rest of the water out
- replace spark plugs and run engine for a 1-2 minutes
- drain oil/water mix from engine
- replace oil filter and oil, run for a 5 minutes
- drain oil from engine
- replace oil filter and oil, run for a 15-30 minutes
- check to see if the oil is milky at all, if it is, replace oil and filter again and run engine

As said before, you need to do this NOW

 

[johnbell47]

Re: water leak test gone wrong

Thanks to all of you for the advice, I knew better than that, I just wasn't thinking. A lesson well learned. I sucked the water and old oil out, I pulled the spark plugs, turned the engine over by hand and then with the starter, blew lots of water out. I WD 40ed the cylinders and will blow that out tomorrow, I am bushed, hot and sweaty. I intend to change the oil at least twice. I am running synthetic, but think I'll use cheapo for at least the first two changes. Again, I did not need the critisim, but I guess I deserved it. I just wasnt born as smart as some. Thanks Again!!

 

[fishrdan]

Re: water leak test gone wrong

I WD 40ed the cylinders and will blow that out tomorrow,,,,,,,,,,,,,,

Tomorrow??? I take it you haven't started the engine yet? You need to get that engine running ASAP,,, as in yesterday!

Seriously, the longer moisture sits in the engine the more damage it will do. I would use cheap oil too for the flushing, WalMart brand, in the 2 1/2 gallon jug.

 

[johnbell47]

Re: water leak test gone wrong

O.K. its after dark and cooled off, I'll go crank the motor.. durn, I been crawling around houses all day, but this is important!!.. I'll let you know what happens..

 

[boattech]

Re: water leak test gone wrong

I would flush a couple gallons of diesel fuel through the engine before you waste alot of money on several oil changes. I usually take off the oil filter, drain all the water and or milky oil out of the pan, then fill with 2 gallons of diesel fuel, take an air compressor hose and lightly apply air pressure to dip stick till you see alittle diesel leaking out of oil filter hole. then let it sit and boil like that for 15 - 20 minutes. then drain it out, then add the oil and filter and run it, after a good hot run do another oil change and go on with life. If you once get milky oil it will take forever with oil changes to get it clean again. the diesel will disolve the thick milky oil and pull it out

 

[johnbell47]

Re: water leak test gone wrong

Engine is running fine, I rigged a vacuum pump with 1/4 inch icemaker line running through a glass jar and am decanting the water out of the very bottom of the oil pan every morning. I did'nt get but about a pint out of the bottom of the pan this morning. oil looks pretty good but still milky after a run. I am gonna decant again in the morning, heat the engine for about 15 minutes then change oil and filter again. Crisus almost over. Thanks to everbody for the good advice. It's good to have help. Real good.

 

[johnbell47]

Re: water leak test gone wrong

of 3rd oil and filter change. detected about 1/8 inch of milk on the dipstik, thought about this all day. Added one pint of Heet to the crankcase through the dipstik and waited one hour. sucked that out and put fresh oil in with a new filter. ran the engine for one hour, temp was 160, oil is perfect. The alcohol in the heet inhibits or absobs moisture, worked pretty good here. just a thought.