oil in bilge #2

sti1471

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oil in bilge

I took the boat out this morning for another test / tune run. The boat ran very well except for one issue that I noticed. I have a mud colored oil in my bilge bay. I can see where it slowly dripping out of. It is dripping out of the starboard side of the flywheel plate (circled in red in photo). There does not appear to be much water if any with it, as it is thick oil that was VERY hard to get off my hands when washing them in the restroom.

I checked my engine oil and there is no water in the oil and it is normal oil color on the dipstick, and the oil level is not low. I drained my outdrive oil and it came out green and had no water or shavings with it.

Any ideas as to where this might be coming from?
 

sti1471

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This is my 2nd post on this. for some reason the other post will not let me edit it or add photos so I think it got corrupted.

I took the boat out this morning for another test / tune run. The boat ran very well except for one issue that I noticed. I have a mud colored oil in my bilge bay. I can see where it slowly dripping out of. It is dripping out of the starboard side of the flywheel plate (circled in red in photo). There does not appear to be much water if any with it, as it is thick oil that was VERY hard to get off my hands when washing them in the restroom.

I checked my engine oil and there is no water in the oil and it is normal oil color on the dipstick, and the oil level is not low. I drained my outdrive oil and it came out green and had no water or shavings with it.

Any ideas as to where this might be coming from?

 
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sti1471

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No ideas where this water is coming from? I know it could be the rear main seal, but I am confused as to where the "coffee" color is coming from. This would indicate that the oil has water in it. The drip is slow and it is not like a water drip, it is more of a slow goopy thick drip, so I assume the leak is not a big one, but I just can't understand where the water getting mixed in.

After posting the original post, I went out and drained all the outdrive oil and it was full and water free, so it is not coming from the outdrive. I then leveled the boat and checked the engine oil. It looks like the engine oil is about 1/2-3/4 QT low. However the color of the oil on the dipstick is good, there is no indication of water in the engine so I am assuming the engine block is not cracked. so it appears that the oil is mixing with the water after it leaks out of the engine.

It is possible that it is the trim hydraulic fluid and not engine oil and if it could be, why would it be dripping from the flywheel cover?

Any ideas?
 

sti1471

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OK so I removed the dust cover from the flywheel cover. This is what was on the other side. Looking at the start height and pattern I am hoping someone might know what might be leaking.
 

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s.hadley81

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It sounds to me your yoke seal in the upper on the drive is leaking (pushing oil out of the drive through the gimbal) Pull your drive and pressure test it I would say your gonna find that seal is blown at least check your drive oil if it's low it in your bilges and if you keep running it your gonna find out the hard way (blown outdrive do to lack of oil
 

sti1471

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If the yoke seal was broken, wouldn't there be water in the outdrive oil? I drained the outdrive and it did not appear to be low and there was not 1 drop a discoloration in the oil that came from the outdrive, it looked clean as a whistle.
 

sti1471

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The above picture is a picture I happened to get with my camera sticking it back in the flywheel area. It looks like a crack in the flywheel. would this cause an oil leak, or is this not related but another issue I found by accident?
 

GA_Boater

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I think the cracked flywheel is causing an imbalance at the end of the crank and the rear main seal is leaking. The color of the oil on the plate and in the bilge may be an oil/powdered metal mix. Does it feel gritty? If it was water, it would gradually separate from the oil. Apply some heat to the back side of the plate, water will boil off. Protect yourself from splatter.
 

81 Checkmate

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I think GA Boater is right...dont like the looks of that last pic. Flywheel out of balance and it wasted your crank seal...... If it were me id pull the motor now and have a look. You keep running it...well..things mighta start flying...
 

sti1471

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thank for the feedback guys. You are correct, I am going to take the boat over to my buddies house where he has an engine hoist. Going to pull the engine and take a look at what is going on back there.

I now have 2 more questions.

Can the flywheel be tig welded and repaired if done by a welding shop or should I start looking on ebay for another flywheel?

When you say that there might be metal shavings, what would the metal shavings have came off of? would the shavings be from the oil seal or from the crankshaft itself?


While I have the engine pulled I will also replace the oil pan gasket and some other things. If there is anything that is wise to look for and replace while it is pulled, please let me know as I don't want to have to pull it again anytime soon.

Hopefully I can have it back together before the water level is too low to launch it again :(
 

GA_Boater

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Get another flywheel. Welding could knock the balance off even more and the heat could weaken it as well. As far as where the metal is coming from, the tear down should expose that. It could be from the seal, the flywheel and possibly the coupler. Look when the motor is pulled.
 

sti1471

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Is there a specific flywheel I need to install on this. are all 3.0L flywheels the same or is there a difference in tooth count, bolt pattern? From what I can see is that it is a 14" GM small block flywheel but that is all I can find online. Is there some GM vehicles I can pull this off of in a junk yard?
 

Bondo

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Is there a specific flywheel I need to install on this. are all 3.0L flywheels the same or is there a difference in tooth count, bolt pattern? From what I can see is that it is a 14" GM small block flywheel but that is all I can find online. Is there some GM vehicles I can pull this off of in a junk yard?

Ayuh,.... I believe the change was 1990,.... That motor went from 2 pc. seal, to the 1 pc. seal,....
I don't see the year mentioned, so,....

Ya either need a 14" flywheel, for a Pre-'90 3.0l GM motor,....
Or, a 14" flywheel for a '90 to present 3.0l GM motor,......
I believe the bolt pattern is 3, 1/2" pre-'90, 'n 3" post-'90,....

Btw,.... as noted, weldin' cast iron, ain't gonna happen on a flywheel,.....
You could buy 2 New 1s, for the cost of "Tryin'" to fix that 1,....
 

sti1471

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There is a guy here local that is parting out his 1977 Mercruiser 165. Would his flywheel and or 2 piece seal collar fit my 1984 Mercruiser 140?
 

81 Checkmate

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Just me but.....Id pull the motor...see whats wrong and go from there.......I woudn't go buying parts untill i knew what was wrong first....
 

GA_Boater

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Just me but.....Id pull the motor...see whats wrong and go from there.......I woudn't go buying parts untill i knew what was wrong first....

+1 on this. The motor has to come out to do any work anyway. Pull the motor, a least slide it forward if you have the room, and access the damage. And post your serial number so the proper parts can be ID'ed.
 

Bondo

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There is a guy here local that is parting out his 1977 Mercruiser 165. Would his flywheel and or 2 piece seal collar fit my 1984 Mercruiser 140?

Nope, that 165, Ain't a 3.0l,....
 

sti1471

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I removed all the connections to the motor last night and I will be pulling the motor on Thursday afternoon so I will pull the motor and then order parts.
the serial number to the engine (located on the red tag on the valve cover) is 6703940
 
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