Milky oil water in oil 1966 OMC stern drive

"i have a 1966 120hp OMC stern

"i have a 1966 120hp OMC stern drive with a chevy 153 inborad engine. the motor runs fine, i bought the boat for 300 bucks and it had obviouly been sitting out in the weather for a while. it took me about an hour to get it started, as well as new plugs, cap and rotor and cables.

once it fired up, it ran strong, sounded good. put the prop in a tub of water to check the cooling system and everyting was good. let it run for about an hour and a half at idle and throttled it up a bit to see how she ran.

after the tub test, i checked the oil and it was fine, no leaks that i couild see. I took it to the lake later that day, ran it for about an hour at all throttle ranges. when i stopped back at the dock, i did another oil check to be sure i wasnt losing oil and it was milky!

i quikly took the boat home, pulled the oil plug, drained it, changed it, and got a new filter. put it back in the tub of water to see if i could isolate the leak, but to my suprise.. after 2 hours of running in the tub of water. there was NO WATER in the oil.

so... another lake test. took her back out. took it out of dock, throttled it up for aobut 2 min, turned the motor off, pulled the dip stick and sure enough, there was water in it!

help!! i dont know why it leaks water into the oil at the lake but not when i run it at home. i have the entire prop and water intake submerged at home in the tub.. what changes in the lake?

any help would be great, i am at a loss.. this is my first boat. i am an engine wiz, but the stern drive is all greek to me. what am i missing?

thanks!"

"lost me - which compartment i

"lost me - which compartment is milky? The engine oil?, or 1 of the 3 drive oil compartments?"

"the engine oil, sorry [img][/

"the engine oil, sorry

to clerify and make it simple, when i run the boat in the lake, i get water in my engine oil.

when i run the boat at home with the outdrive in a barrel of water, i dont get water in my oil.

has something to do with the boat being in the lake, but i dont know what....

could it be that the stern drive is siting lower in the water and water is getting in from some other source? i have the stern lifted when i put it in the water, then i lower it once the boat is off the trailer... dont know if water could be getting in that way. i dont even know if there is anything other than the water intake port that water can get into and make its way into the engine oil"

"You're still not really c

"You're still not really clear - when you say "in the lake", you mean backed in on the trailer for 10 minutes?, or you mean water skiing? Big difference there.
If water skiing etc, engine is under load - higher water pressure - higher temps - I would suspect a crack in the block, head or haed gasket failure.
The engine is not connected to anything that can leak from the transom or hull. Water is getting in from the engine's cooling system.
Other possibility is a failing exhaust manifold - only when it gets nice and hot will the cracks open enough to flood the exhaust side - then you shut the engine off and water runs in the ports past the rings.
Need to pressure test the block - 5 or 10 psi applied to where the hose from the sterndrive normally feeds water to the thermostat - block the exhaust manifold water lines. Then remove the manifold and inspect/change"

"sorry [img][/img] yes when i

"sorry yes when i mean the lake i mean running down the lake at half to full throttle. at and home i just let it idle. when i got the boat there was s amll crack on the block where water was coming out when the motor ran, i used some JB weld on the crack and it stopped the water.

i didnt think anything of it really until you just metioned cracks. it would make sense that the crack bridged an oil and water passage.

i dont suspect it is worth the money to have the engine replaced. since the crack seems small enough to not allow water to pass through at idle, only under load, is there anything you can put in the water to possibly seal it? maybe run the motor in a closed water system for a few hours with some stop leak or something?

or am i better off trying to locate another motor for this thing. in the few min i have been looking after reading your post, i have found really nothing. its a chevy II 153/omc 120. seems to be a fairly rare motor. ugg.

i am going to go buy a head and intake manifold gasket today and give that a shot, as well as put my air tank hose on the manifold.

any other ideas/tips?"

"I just sold a complete 2.5 lo

"I just sold a complete 2.5 locally for $650 - it had about 100 hours running time since new and was like new. I sold another last year for $350 - I suspect it was cherry as well, but I didn't know the history so I dealt it cheap - so, my point is, they're around-I also saw a whole running 1962 ChevyII 4 door that sold on eBay for around $500. if the block is cracked internally, you cannot fix it - it's scrap -"

"i didnt even think to look fo

"i didnt even think to look for the car version of the motor.. lol. well i will look around then. If you come accross a motor i will buy it from you and pay for shipping. let me know, my email is [email protected]. i will check ebay now.

i am looking for a 1960's chevy II? i bet the local junk yard has one of those."

look locally - shipping runs a

look locally - shipping runs around $1000 to $2000 for freight to lower 48 and crating - it's looney- a lot of places don't even handle engines because they can leak oil and destroy other cargo