7.4L just purchased boat , water in oil. How to identify issue ?

[jeffc]

New to the forum and like to say hello to all. I just recently purchased a 1999 Sea Ray 260 SD. It is powered by a 7.4l Merc,with only 150hrs. Fresh water boat with open cooling. Oil was crystal clear and new looking when I bought boat 2 weeks ago. Had a retired boat mechanic come inspect the boat... he was impressed with its excellent condition. We started motor in driveway and no water was coming out of drive. He stated that the sea water pump was most likely shot. I purchased a repair kit and installed it all good water is pumping. Ran motor for about 5-10 min and checked dip stick. Milky color to it and removed oil filter and very milky. I am pretty sure I got screwed and the fresh oil was to hide a previous issue. Where do I start to eliminate the issues. Mechanic suggested to start with oil cooler. Thx in advance for your input

 

[rondds]

Pull the plugs and see if there's any moisture on/in there. Pull the oil cooler and bring it to a radiator shop that also does marine ( alot of them do). Pull the exhaust elbows and see if there's water in the exhaust gas passages of the manifolds - the gasket btwn the elbows and the manifolds are notorious for failing. Could be a head gasket or a cracked cylinder head, or cracked block. Start with the easy stuff first. If water showed up that quickly it was most likely that a recent oil change was done to cover up the problem.

When you have the plugs out do a compression test as well. Problems are most often in cylinders 5 and 6 (beneath the exhaust elbows).

 

[RollerCoastr]

Vancouver BC or WA? Canada seems to have stronger consumer protection laws than the states. I know that you don't want to sell a home in Quebec that has latent defects... Do you have any recourse against the seller?

 

[Searaybio270]

+1 on what Rondds wrote. I am going through the same thing and my mechanic is doing a lot of that. Mine did remove the exhaust manifolds and risers to check them and then cleaned them up. Replaced the oil as mine had water in it. New spark plugs. Just heard late yesterday after getting it all back together I still have the same issues. He is thinking of replacing the exhaust manifolds and risers. I also think he did a leakdown test.
Hope these helps a little.
Joe

 

[Air O'Nautical]

Hold on....
"no water out of the drive"
Then, where's the water coming out from ?

If you have a garden hose on the drive and force too much water into the system...you WILL back up into the exhaust. You should not use full city water pressure because, it's too much for the system to swallow at idle or low RPM.

So far sounds like you caused the problem. Save the motor by pulling all plugs ASAP and spinn the starter to expell water out. Spray oil, WD40, marvel mystery or something to expell the water. Then, change the oil and filter.

Let's start there.

 

[skolbe]

I have a friend that bought a boat much like you did and did the same thing. I wouldn't assume that the seller hid something at this point.

 

[rcknecht]

+1 on what Rondds wrote. I am going through the same thing and my mechanic is doing a lot of that. Mine did remove the exhaust manifolds and risers to check them and then cleaned them up. Replaced the oil as mine had water in it. New spark plugs. Just heard late yesterday after getting it all back together I still have the same issues. He is thinking of replacing the exhaust manifolds and risers. I also think he did a leakdown test.
Hope these helps a little.
Joe

Joe, Sorry to hear you are have poblems... I thought you had replaced you manifolds and risers...

 

[almostenuff]

Joe, this sounds very similar to a situation I had several years ago with a non-SeaRay. The pump was bad, so when the seller "pumped" antifreeze into the engine, it didn't really make it into the engine. Then he put new oil in it and sold it to me. Only cost me $2000 MORE to get a different engine and sell it...

 

[Ten Years Gone]

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[sdleo26]

Hold on....
"no water out of the drive"
Then, where's the water coming out from ?

If you have a garden hose on the drive and force too much water into the system...you WILL back up into the exhaust. You should not use full city water pressure because, it's too much for the system to swallow at idle or low RPM.

So far sounds like you caused the problem. Save the motor by pulling all plugs ASAP and spinn the starter to expell water out. Spray oil, WD40, marvel mystery or something to expell the water. Then, change the oil and filter.

Let's start there.

Can't argue with that logic....

 

[Bt Doctur]

No body should ever purchase a boat with out a on-water test for at least a 1/2 hour of running time.

 

[Air O'Nautical]

Hold on....
"no water out of the drive"
Then, where's the water coming out from ?

If you have a garden hose on the drive and force too much water into the system...you WILL back up into the exhaust. You should not use full city water pressure because, it's too much for the system to swallow at idle or low RPM.

So far sounds like you caused the problem. Save the motor by pulling all plugs ASAP and spinn the starter to expell water out. Spray oil, WD40, marvel mystery or something to expell the water. Then, change the oil and filter.

Let's start there.

More, now may as well check the compression while all the plugs are out.
We really need to get the motor running and up to temp to evaporate the rest of the moisture out of the system and change the oil again....

 

[jeffc]

I am going to pull plugs tonight and see if I can get oil cooler off as well. It was mentioned to look at elbows for water ..how would that water get into the crankcase ?

 

[jeffc]

More, now may as well check the compression while all the plugs are out.
We really need to get the motor running and up to temp to evaporate the rest of the moisture out of the system and change the oil again....

Mark thx for he suggestion but my mechanic ( he is older and retired) said that the chances of water coming into the from the garden hose(muffs) is very unlikely

 

[jeffc]

Having had to replace the sea water pump with all the blades gone on the old one..... I can only suspect this was the root cause of what I am currently dealing with water in the crank.
Is there a over-heat cut off breaker on these motors to protect melt down ?

 

[Air O'Nautical]

I am going to pull plugs tonight and see if I can get oil cooler off as well. It was mentioned to look at elbows for water ..how would that water get into the


The sooner the better.
The impeller damaged didn't have anything to do with getting water in the engine..
Deal with the impeller after clearing the motor of as much water as possible.
Were trying to prevent rust!

 

[Air O'Nautical]

Having had to replace the sea water pump with all the blades gone on the old one..... I can only suspect this was the root cause of what I am currently dealing with water in the crank.
Is there a over-heat cut off breaker on these motors to protect melt down ?

Over heat cut-off....Nope. The temp gauge and usually a horn are the norm, tho neither will auto shut down the engine.

 

[Air O'Nautical]

Thinking this through,

What ever it is...pull the plugs, spin it, oil it, spin it again, compression test it.

Worry about oil cooler and impeller next..

Report back..

 

[jeffc]

In talking with my son who has stripped and rebuilt a ton of motors ....his comment is if there is water in the top of cylinder the motor would run like crap and white smoke would be exiting exhaust. I was able to pull oil cooler and did a little compression test under water to see if bubbles were existing but all looked good. Got 2 spark plugs pulled from one each side and plugs look okay. So its looking like had gasket or cracked block... if anyone has other suggestions please let me know.

 

[Ten Years Gone]

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