Water in Oil?-Now What?

[UNSUREBOATGUY]

Hello,

I just bought a 1987 four winns 160 freedom with 3.0 Mercruiser yesterday. I'm pretty sure there is water in the oil. Is there an easy way to be sure? I changed the oil to try to find out-it came out thin (granted, it was warm, but I think thinner than it should be), and more drained out than there should have been in the engine.

Also, assuming there is water in the oil, is there an easy way to tell what the cause might be (gaskets vs. crack.) We took the boat out for the first time today, it seemed to run pretty well for the most part. The temp was good, it got up to speed fine, but the oil pressure gauge seemed to read a bit low, but as I do not know the boat-not real sure on this one. It was a little hard to restart on the water, but not too bad at first. Then as we were going, it started to run poorly and lurch a bit until it sputtered out. It was then difficult to restart. Once I did get it restarted, it seemed to run fine long enough to get us back to the dock.

I'm pretty sure I was bamboozled-I was told the boat had no problems. Our little family went out on a limb for what seemed to be a really good deal. It recently had a new alternator installed, plugs and points. The seller suggested I replace the plug wires and cap/rotor when I get a chance. I just want to know if I can just replace a gasket or two, or if this is a lost cause. Please help with the water in the oil troubleshooting if you can. Thank you very much.

 

[jtybt]

Re: Water in Oil?-Now What?

If the engine has been run at all, the oil will be milky if there's water in it.

Gas leaking into the intake will eventually get into the oil and thin it down.

Put some on a stick and smell it gas and try to light it.

 

[UNSUREBOATGUY]

Re: Water in Oil?-Now What?

Oh, and on closer inspection, it looks like there is rust around where the spark plugs thread in.

 

[UNSUREBOATGUY]

Re: Water in Oil?-Now What?

The oil was not milky, really-looked more like really dirty water. I did smell it not really a strong odor of gas. I drained it all out of the motor-I suppose I could put a little on a piece of metal and try to light it. Is it possible that a quart or two of gas could have leaked into the oil? Thanks.

 

[Maclin]

Re: Water in Oil?-Now What?

The gasoline smell would be very evident if it is enough to thin the oil.

After it has been running take the flame arrestor off and look down the carb throat to look and listen for fuel draining into the intake manifold. Also, the spark plugs will tell a good story too if it has been running rich due to too much fuel in the intake.

If you do suspect fuel contamination to any degree you should change the opil and filter again and determine the cause before running it very much.

You should do a compression test to see what the general health of the engine is even though your sypmtoms do not indicate a real proble there. But then you know if the engine needs attention now or is good to go for a few seasons.

 

[Apollo75]

Re: Water in Oil?-Now What?

It could be many things.

I would change the fuel filter ---- get a quart mason jar or equivalent and dump the contents of the filter in it --- see what you have after a couple hours of sitting.

Then if there is water and crud in there ---- put some good fuel system cleaner --- and some sta-bil and maybe a couple ounces of marvel mystery oil with some good premium gas and run it around the lake close to the docks --- don't try a trip to Hawaii --- should be fine.

My old boat skipped a few beats the other day --- fuel filter was full of crud and water --- my fault -- should change if more often :redface:

Good Luck

OFM

 

[BAproject]

Re: Water in Oil?-Now What?

You would definitely know if there was water in the oil!

You can easily pull the dipstick and see if there are little coagulated white globs on the stick.

If you see them then I would start with a compression test and see if the head gasket or head is cracked.

You said the boat was running fine, so this may not be the case but it's a pretty easy diagnosis and will give you piece of mind. I think

-BAproject

 

[UNSUREBOATGUY]

Re: Water in Oil?-Now What?

Little update-I drained most of the oil from the motor into a milk jug yesterday afternoon. This morning I took a look at the jug. I was thinking that after this amount of time, if there was oil in the water, it would have separated by now. Is this the case? There is no evidence of separation. I took the cap off and smelled it-there may be a smell of gas-not super strong, but it defininatly doesn't just smell like oil. My wife said it smelled like a Sharpie marker.

When we first went out on the lake yesterday, the boat was idling a little rough, more like it needed a tune up than like there was a major problem. It seemed to run fine-got it up to around 33 knots. Again, this is the first time we have run the boat, but that seems pretty good for a 16' boat with the 3.0 mercruiser. Then we started having the problems as I have noted.

Any more thoughts? Thank you very much!

 

[UNSUREBOATGUY]

Re: Water in Oil?-Now What?

What would be the affect on how the boat runs if fuel is leaking into the intake manifold?

 

[Apollo75]

Re: Water in Oil?-Now What?

The oil would look like a milkshake with water in it --- if there was a lot of fuel in it that milk jug would have melted and emptied the oil all over the floor by now.

Small things first --- check the ignition circuit, points, plugs, cap, rotor --- change the fuel filter


Good Luck

OFM

 

[BAproject]

Re: Water in Oil?-Now What?

Hard to tell what the affect would be. You should pull one of the spark plugs and take a look. There are archived forums that will tell you what the color of the plug indicates, rich/lean, etc.....
I would pull the intake manifold off and replace the gaskets! Not hard to do at all. If the gaskets are hosed then your going to be leaking gas into your oil. Don't know the effect but it's going to thin out your oil, hence breaking down lubrication properties.

While you have the intake off, pop the carb and inspect/clean it out. There's probably junk in the float chamber.

Is this a salt or fresh water boat? Salt water sitting inside the cooling passages in the heads can destroy a gasket, hence gas dripping directly into the engine.

-BAproject

 

[UNSUREBOATGUY]

Re: Water in Oil?-Now What?

it is a fresh water boat. I never thought there was a possibility that gas could find its way into the oil, especially a fairly large amount.

 

[Bondo]

Re: Water in Oil?-Now What?

I drained most of the oil from the motor into a milk jug yesterday afternoon.

Ayuh,... If you drained the oil,+ it fit into a gallon milk jug,...
I figure the only problem you have is You....

Finish changing the oil,+ Go Boating...

 

[UNSUREBOATGUY]

Re: Water in Oil?-Now What?

Ha, Ha, the rest of the oil I drained into a 5 quart empty oil bottle along with a little oily water from the bilge (oil that I spilled). It was definitly more than 4 quarts in the engine-probably more like 5 to 6.

 

[UNSUREBOATGUY]

Re: Water in Oil?-Now What?

Is it possible that fuel might get into the engine through a fuel pump with a ruptured diaphragm? I was looking at the owners manual (kind of amazing that I got it with the boat) and read about a "fuel pump sight tube." Apparently, if there is fuel in the tube, I am supposed to "have your authorized Mercruiser dealer replace the fuel pump immediately." It's a little hard to tell what is in the sight tube (it's really more of a yellowed clear hose that runs from the top of the fuel pump to the carb), but it looks like there might be some fuel in it. I didn't notice if there was fuel running through it when the motor was running-didn't know to look at the time. I am trying to avoid running the motor until I replace some parts that might be causing the oil contamination-trying to avoid having to change the oil again so soon. Maybe it is unavoidable. The fuel pump is a mechanical pump, with a gasket, bolted to the block right next to the oil filter. I would think that if the diaphragm was ruptured, the pump would pump gas into the block as well as up to the carb. Does this make sense to anyone?

 

[bruceb58]

Re: Water in Oil?-Now What?

If you have fuel in that tube, your diapragm is ruptured and sending the extra fuel into your carb. You should replace the fuel pump. Make sure you replace with a marine fuel pump.

 

[Maclin]

Re: Water in Oil?-Now What?

Look at the spark plugs. They will tell you if the carb is leaking too much fuel into the intake. If the plugs look normal then the carb is probably not the culprit.

Fuel is thin and can get past the rings easily, so if a carb leaks bad enough to drain itself then fuel can get into the crankcase in fairly large amounts over time.

No more think, time to do.

 

[UNSUREBOATGUY]

Re: Water in Oil?-Now What?

The plugs looked ok, but the guy who sold me the boat, told me he replaced the plugs. How fast do they get covered in soot?

I ordered a new fuel pump along with cap/rotor, plug wires-I'll take a good look at the carb as well. We'll see what happens. Thank you for the input.

 

[Maclin]

Re: Water in Oil?-Now What?

If the carb is leaking then they will be wet and black. Your description of how the engine runs seems to lean away from the carb, but at higher rpm's the too-rich condition can clear up. But idling is almost impossible if the carb is leaking, you have to keep the throttle open to clear the flooding, that kind of thing.

Report back findings like that, keeps us all on the right track.

 

[UNSUREBOATGUY]

Re: Water in Oil?-Now What?

Hey, Good News!

I replaced the fuel pump, and plug wires and cleaned the carb. No more fuel in the oil! (I took a good look at the old fuel pump-the diaphragm was cracked in a few places-I'm sure it was pumping fuel into the crankcase.) It runs much better too (surprise, surprise.) I changed the oil and filter twice to get rid of the contaminated oil and took the boat out on Sat. Still could idle a little better, but probably nothing a tune up (cap, rotor, adjust points and timing) shouldn't fix. Thank you all for the help leading me in the right direction. I know much more now about sterndrive boats than I did before-just with I learned all this before rushing into the purchase. Lesson learned-it seems like it turned out OK after all though.

By the way, the tach seems to be malfunctioning. It seems to read about 1000 rpm slow at speed and gets stuck at 1000 rpm when I stop the motor. I was going to clean the contacts to see if that might be the problem. Any other suggestions? I was running the boat at what the tach told me was 4500 rpm, but the throttle was at about 2/3 and the motor sounded like it was cruising comfortably-not at WOT. The speed was around 20 with 3 adults and two kids. I gently increased the throttle to WOT and got the boat up to around 30. The engine never sounded like it was over revving. Anyone have a good idea what speed I should expect for this boat? 1987 Four Winns 160 Freedom with 130hp 3.0 mercruiser with 14 x 19 prop. Also, where should I look for a reasonably priced test tach? Or should I just purchase a new one for the boat-assuming the contact cleaning doesn't do the trick?

Thanks again and God bless.