89 Wellcraft Mercruiser 3.0 Water in oil?

[jschick]

I just bought a 89 Wellcraft with a 3.0 Merc. the boat is in mint condition except the owner says it gets water in the Oil, I acctually will be picking the boat up this weekend so I have not looked into the engine yet (the price was right) he was told the block is cracked. but he is by no means very Knowledgable on his boat! but he has always had it serviced at a marina. the boat does run, and seems fine out of the water. I have no idea how long it takes to get water in it andit was supposidly winterized!
so a few questions. since it runs I assume it can't be a head gasket. so i plan on first removeing the manifold and checking it. if it is ok, then what?
and can a car 3.0 block be used if I swap out all the parts? I can rebuild the engine but not familiar with what is interchangable with my 89 3.0! can anything else drop in? V6 V8 do I need to find a Marine block? any tips and pointers would be helpfull. this boat you could eat off the current engine, thier is not one drop of oil or dirt in the engine bay! is their anyplace this engine block comonly cracks and would it be repairable? since it runs out of water I assume a water jacket someplace, but I will also do a compression test when I get it home!

thanks

if the in

 

[jschick]

Re: 89 Wellcraft Mercruiser 3.0 Water in oil?

forgot to ask, I assume if I run this boat with Muffs and a hose I can test to see how long it takes to get water in the engine, and possibly run the hose and don't start the engine to see if I get water in the pistons?
will doing any of this tell me anything?

 

[jschick]

Re: 89 Wellcraft Mercruiser 3.0 Water in oil?

thanks,
my thoughts were IF the block is cracked. i may find a 3.0 auto engine for $100 and use the block only, swap out all the internals. or I have seen many used Junk boats for under $1000 with a running 3.0 swap engines and resell the junk boat.

if I do this are their any issues with different 3.0 engines. say early 80's or maybe even older? I would think going to a older engine may not be as good as rebuilding a Auto block to marine. but are their maybe any benifits in going to to a older 3.0 engine? any Plusses or minuses to any of these routes?

if I get a Auto block, i would obviously do rings and gasgets and seals, maybe bearings.
I did find a Parts engine on Craigs list, it is missing a piston, is their a comon place to check for cracks in the Block? should I even think about a Non running parts engine or used block. I see on Ebay many of them have cracked cyl walls which is easy to spot!

 

[danond]

Re: 89 Wellcraft Mercruiser 3.0 Water in oil?

...and next time, buy a boat with a working engine! Water in the oil is about as expensive as it gets.

 

[johnnyd]

Re: 89 Wellcraft Mercruiser 3.0 Water in oil?

It sounds like the exhaust manifold. Water cascades over the exhaust to cool it down, if it didn't it would be too hot to pass through your bellows. I had the same problem. The exhaust manifold is probably cracked above the engine exhaust port and is going directly in to a cylinder. When you get the boat take out the spark plugs and see if you have water in a cylinder, or see if a spark plug is wet. If you do, replace the manifold.

 

[jschick]

Re: 89 Wellcraft Mercruiser 3.0 Water in oil?

I have found 2 local running 140 engines for sale but one is a 71 and one is a 74. i don't want to go this old but will these engines drop right in? will any 3.0 140 hp drop right in from 1970 and up.
I will be picking up the boat from storage at the Marina who has serviced this boat, so my assumption is the block is cracked as they say it is. but I will pull the manifold prior to pulling the whole engine just to make sure. but now I have a few more questions regarding the 3.0 140 engines, are they ALL interchangeable?
if I do buy one of these local engines, are the manifolds and other parts interchangeable?
would It be best to swap out any parts from the 89 original engine to the replacement older engine? I assume keep the newer carb? possibly distributer??

sorry for the list of questions but I know how used parts come and go this time of year and I may just buy one of the engines to have just in case! the Guy only wants $175 for 71 and it runs. and the other 74 is $300 .

so any info I can get on the engines would be great!!

 

[johnnyd]

Re: 89 Wellcraft Mercruiser 3.0 Water in oil?

I don't know about the 140 hp. I do know the 170 & 190 hp are the same the only difference is the intake manifold on the 190 takes a four barrel carb.

 

[Maclin]

Re: 89 Wellcraft Mercruiser 3.0 Water in oil?

Exhaust manifold or risers or gasketing will not put water into the oil. Water from exhaust can only get into the top of the cylinder, and usually only after shutdown. If severe enough it will cause hydrolock the next time it tries to turnover. Water can leak past the rings and into the crankcase but only after a very long time and only if the cylinders and rings are in really bad shape.

Water in the oil is almost always from cracks in the internal coolant water passages of the engine block and almost always from improper winterization.

As far as testing for the condition, what did the oil on the dipstick look like? Did the guy use the boat and just change oil all the time or what?

Running on muffs may not let it get hot enough to leak into the oil much so if the oil was just changed it may not show up, but out on the water the engine block will be stressed and leak coolant water into the oil.

 

[Maclin]

Re: 89 Wellcraft Mercruiser 3.0 Water in oil?

Regarding 170hp and 190hp 4 cylinder Merc engines, those are the famously infamous 3.7 and are not a drop in replacement for a 3.0.

 

[jschick]

Re: 89 Wellcraft Mercruiser 3.0 Water in oil?

thanks,
now the oil is clean and it runs, all I have is what he told me, which is their was water in the oil and he was told the block is cracked? so I guess I am stuck either just running on muffs or taking it to the lake?

any info regarding the older 3.0 engines? are all 140 engines interchangable, any problems putting a running 140 from the 70's in the 89?
so far I have found 4 local engines, one is supposidly a good short block.
3 are running engines a 71 for $150 a 74 for 250 and another year unknown but he thinks early 80's,looks like a newer engine for $375?

 

[Fossilized]

Re: 89 Wellcraft Mercruiser 3.0 Water in oil?

To add to an old thread - I just found the source of water in the oil of my 350.

It is a salt water veteran. A hole has been created on the bottom of the intake manifold under the thermostat. There is a little pile of corrosion on the lifter valley where water has been leaking for some time.

 

[intrepidvoyager]

Re: 89 Wellcraft Mercruiser 3.0 Water in oil?

Check the riser ......just did a friends 3.0 with water in oil issue ....... riser leak on engine side of hump right above manifold exhaust ..... VP engine with combi manifold