Water in Oil

Curtis Macdonald

Curtis Macdonald

New Member
May 24, 2018
25
Boat Info
1990 Sea Ray Sundancer 250DA
Engines
5.7 SE106 stern drive
Recently bought this 1990 250DA with the 5.7. The boat never has run right since I bought it. I changed the oil and serviced the lower unit when I first got it and have only run it about an hour.
Died on the lake, had to get towed in. Loaded it on my trailer and started taking a look at it in my shop Found about a gallon of water in the pan, so, looks like the motor is coming out.
Question, in order to pull the motor, do I need to drop the outdrive? How does the motor separate once the bell housing bolts are removed? Decent mechanic, but little Mercruiser experience.
I want to rebuild it so I know what I have moving forward.
Thanks for the info, in advance!
 
Drive has to come off since the drive shaft coming out of it is engaged into the coupler which is bolted to the flywheel.

There are two bolts in the back that attach the motor to the transom housing and two adjustable motor mounts in front that are on the stringers.

The front mounts control the engine’s positional relationship to the drive, so upon reinstallation you’ll want to use the proper alignment tool and have a helper.

There’s no shortage of info available on that procedure when you get there.

Good luck.
 
Soulshine said:
Drive has to come off since the drive shaft coming out of it is engaged into the coupler which is bolted to the flywheel.

There are two bolts in the back that attach the motor to the transom housing and two adjustable motor mounts in front that are on the stringers.

The front mounts control the engine’s positional relationship to the drive, so upon reinstallation you’ll want to use the proper alignment tool and have a helper.

There’s no shortage of info available on that procedure when you get there.

Good luck.
Click to expand...
Good info, just what I needed to know. I'll start digging into it within the next week or so. Good news is that I have it inside my shop and have an electric crane. This will make my life easier! I'm sure that proper alignment is crucial, so I will gather the info here as I go back together. This is a very nice boat and I need the peace of mind knowing what condition the motor is in. Thanks!
 
Get yourself the mercuiser manual for that engine and outdrive model. It will help you out.
 
Golfman25 said:
Get yourself the mercuiser manual for that engine and outdrive model. It will help you out.
Click to expand...
Any suggestion on where to purchase the exact manual I need? Several seem to be available from Clymer to Mercruiser but they just cover a specific range, like 84 - 92. I have a 1990 250DA which Sea Ray doesn't readily offer manuals for that model for some reason. A review on the Clymer book says that the manual only covers the motor. I will need specific information relating to removal and installation. Also including alignment procedures. Thanks!
 
You won't find anything specific to the boat because the engines where installed in many different models from many different manufacturers. You're looking for one that covers the year and model of your engine/outdrive combination. Like this:

https://www.amazon.com/Clymer-Mercr...1533218441&sr=8-3&keywords=mercruiser+manuals

It's been a while since I had an outdrive, but it should cover pretty much everything you need to know. Alignment is done with a special tool. I believe it will all be in the book.
 
Well, moving right along. Pulled the 5.7 yesterday, easy peasy. Pulled the exhaust and flywheel cover and found that the ring gear on the flywheel has some worn and flat spots, so this explains the starter issue.
Also removed the spark plugs and found water. Major water in the oil also. So apparently I have a blown head gasket or cracked head issue, thus water in the oil. Kinda like an adventure now. Today, I will pop the heads and see what is going on. Hopefully they didn't let the block freeze and fracture the valley around the lifters.
Planning to totally rebuild anyway, just hoping I have a good block. More to come.
 
How do I check? When I look into the risers, I see the rubber flappers still in place. How can I check the manifolds?
 
Curtis Macdonald said:
How do I check? When I look into the risers, I see the rubber flappers still in place. How can I check the manifolds?
Click to expand...

Manifolds are a maintenance item. Life span depends on if they are exposed to salt or fresh water. If you don't know how old they are it's probably worthwhile to replace.

In salt you get around 5 years in fresh I hear around 10 years. Unfortunately once the water jacket fails it just dump water into the exhaust.

-Kevin
 
Pulled her apart and inspected. Blown head gaskets, both sides. One side worse than the other. Found that this engine has been rebuilt with Enginetech rebuild kit. .060 pistons, so they have pushed the limit with the bore in my opinion. I have always had overheating issues with .060 bore small blocks on street applications. Also, due to the rust deposits from sitting a few weeks, I may be forced to get another block. I don't mind running a .020 or .030 bore, so I will see what I can find. Possibly a sleeve job back to stock, at least I will explore some options now. I still need to pull the crank and see what bearings the crank is running. I know for sure that I will buy new exhaust and risers now, small price to pay.
Any suggestions on the shutters? Material, best performers?
 
For the manifolds and risers: I only use OEM Mercruiser. Shop around online for them. You can usually find a kit for the small blocks that includes gaskets and bolts for around $600.
Are the old heads Vortec? If not, you may want to consider Vortec heads. They’re probably easier to come by these days. You would have to replace the intake manifold too, but if the motor is raw water cooled that is probably trashed anyway.
Unlike a motor that was in a car for 28 years, a punched out 60 over 28 year old raw water cooled motor with two blown head gaskets and a chewed up flywheel may not be worth trying to save.
Especially since small blocks are readily available for pretty good prices.
If the boat itself is really nice and you plan to keep it a few years it might really pay to get a new motor.
 
It's a vortec, with the one piece rear seal. I'm considering just "long blocking" the motor with my cam specs. I have a major local builder that will do it for $1200.....includes gasket set and oil pump. The intake manifold is in super condition.
 
you might want to consider 'stroking' the engine with a different crankshaft.....I have 6.2L (377 ci) stroked engines and really like them.....I think I would go with a 383 stroker engine in this case as long as you don't over power the outdrive.....

good luck and post pics....us 'gear heads' love to see this type work as it progresses.....

cliff
 
What a crying shame! LOL
This is obviously a rebuilt rotating assy that blew the head gaskets on each side between the center cylinders. I believe this is the result of a stuck thermostat, but not certain. I'm not taking a chance on the exhaust or risers either. Buying new OEM Mercruiser exhaust kit. The only question I have, what is the best shutters to purchase? OEM rubber, stainless or what?
This block has been bore to .060, so now it's toast. Bought a .030 prepped block to replace it. Don't want to rework this block and sleeve.
 
Last edited:
Curtis Macdonald said:
What a crying shame! LOL
This is obviously a rebuilt rotating assy that blew the head gaskets on each side between the center cylinders. I believe this is the result of a stuck thermostat, but not certain. I'm not taking a chance on the exhaust or risers either. Buying new OEM Mercruiser exhaust kit. The only question I have, what is the best shutters to purchase? OEM rubber, stainless or what?
This block has been bore to .060, so now it's toast. Bought a .030 prepped block to replace it. Don't want to rework this block and sleeve.
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Click to expand...


sounds like you made the right decision....

unfortunately I cannot see the images.....

cliff
 
Curtis Macdonald said:
It's a vortec, with the one piece rear seal. I'm considering just "long blocking" the motor with my cam specs. I have a major local builder that will do it for $1200.....includes gasket set and oil pump. The intake manifold is in super condition.
Click to expand...

Can’t see the images either.
That long block sounds like a good way to go. Stroker is tempting too. Just keep in mind that the Alpha drives are supposed to only be good up to 300 HP.
 
If the outdrive is a Bravo1 or better I would definitely go with a stroker 383. The 25ft boat could use the extra punch.
 
This is just like a puzzle! I think the pieces are coming together slowly.

So, I bought this boat and have now discovered that the engine has been replaced. It is a rebuilt 5.7 with a .060 bore. It also has Barr exhaust and risers......not OEM Mercruiser.

So, it ingested water, filled the oil pan with muck and started "oil canning" when try to start. That's how I noticed the problem. PLUS, the starter was not engaging correctly.

Pulled the motor and found flat spots on the flywheel ring gear........that problem resolved.

Now, pulled the engine apart and found that the head gaskets were blown on both sides, however, there is no evidence of overheating. Even the thermal button placed in the freeze plug from the rebuild was still in place.

After receiving my Mercruiser book, I read where the riser needs to be at least 13" above the water line. The best I can tell, mine is about 7 - 8" above the water line. I'm figuring that when someone built the motor and replaced the OEM exhaust with the Barr Marine exhaust, they didn't install the correct riser height? There is room, but it's just not high enough to keep the water out. I can see a water line in the riser where water has been sitting.

This boat was stored on a lift when I bought it, but I keep it in the water (fresh). I believe that by keeping the boat in the water, I have exposed the incorrect exhaust issue? When I attempted to start the boat with water in the cylinders, apparently that's when the head gaskets fatigued?

Anyway, new stroker going in, picking it up today. Once I have the engine in the boat, I will do some accurate measuring to determine the correct exhaust height, then buy the correct OEM risers or spacers to raise above the 13" mark!

This has been an adventure! Thanks for all the input guys!!
 
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