1995 5.7 Motor Siezed?

[MAW31]

1995 Maxum 2300 5.7 Mercruiser w/Alpha 1 outdrive. I've owned the boat for 8 weeks from private seller. Boat is super clean, seemed very well maintained, today I rechecked oil and it is full and no water. the gear oil is full too.

I simply do not know where to start to determine if my motor has siezed, or if the problem is something else.

Backstory: After a day on the water, we drove the boat back to our boat lift (florida). It's about a 30 minute plane, followed by 20 minutes of slow speed min wake to the lift. Motor ran and idled at cruise and slow speed just fine. While docking, I had no issues going forward/backward, in/out of gear. I docked with not a clue of any imminent problem.

Fast Forward 5 days later when attempting to start the motor, the starter CLUNKED HARD. It engaged hard but the motor never budged. I jumped to conclusions and thought the starter died. After installing a new starter, it did the same thing. It engages and clunks hard on the flywheel. Both batteries are brand new and fully charged with new cables.

It's not like I ran the motor hard and siezed it. It ran perfect save for a faint whining that I noticed but no one else seemed to hear. That was my only clue.

Where do i begin to look?
1) pull the spark plugs?
2) attempt to manually crank motor?
3) pull the outdrive off?

What is the smart order to go about testing, given what I'm observing? What might be the most likely cause.
thanks everyone.
I'm still getting my head around this all.

 

[Bondo]

Ayuh,.... My guess is failed exhaust manifolds/ risers,... Hydro-locked,...

Pull the spark plugs 'n spin the motor over on the starter,...
Yer in the brine,... Times a wastin',...

Ya gotta get it Runnin',...

 

[MAW31]

Well... you were absolutely correct Bondo. I pulled the plugs just in front of the sunset and water came flowing out. after all plugs were pulled, the motor cranked easily. It spit water everywhere. I"m in a conservation area and when dusk hits, the mosquitos will carry you away. so I covered boat to care for the issue at daybreak tomorrow.

Would you mind outlining what my steps are next? should i put oil in the cylinders first? I have a fresh water source for cooling at the dock and a place called Marine Surplus close by.

Woot! it ain't fixed yet, but at least I've a path outa this mess.

 

[Bt Doctur]

Remove the manifold drains , remove sparkplugs and clear the cylinders. Try to run the motor for 10- 15 seconds to dry the cylinders.
Remove the risers and inspect for the obvious hole. Test manifolds by removing the hose from the thermostat that goes to the bottom of the manifolds.
Place the hose at the same level as the manifold opening, slowly fill hose looking for water in the manifold, leaking will be evident.

 

[Scott Danforth]

get that motor running ASAMFP. your in brine. it has sat for 5 days with brine in the cylinders. every second that tics by is critical.

If your close to Marine surplus, your close to Sarasota. if you need a hand PM me. but pull plugs, fill cylinders with ATF.. spin a bit, put plugs back in and fire that thing up. you need to run the motor to save the motor. then throw your manifolds and risers away and buy new.

 

[MAW31]

Good news, the motor is saved! My problems at first were compounded by the fact that as I was attempting to crank the motor over while it was hydrolocked, I melted the Attwood A/B switch, so my helm went dead along with everything else. This caused me to head in the wrong direction and replace the starter.

Using a voltmeter I traced power to the AB switch and noticed the switch knob was at an angle. Further inspection showed the switch had melted.

Once I pulled the plugs and test cranked the motor, it finally cranked over. yay!

Drained the oil, changed plugs, new oil filter, and have since then taken the boat out twice.
I"m back on the water!

 

[Bondo]

I"m back on the water!

Ayuh,.... But have ya fixed the cause of the hydro-lock,..??..??

 

[MAW31]

No Title

The answer in short Bondo, is no. I had thought i dodged a bullet and the source of the water intrusion was a failed canopy cover that funnelled water directly on top of the motor. I haven't had the boat for that long and this was the first rain the boat had been since purchased. I thought that HAD to be the intrusion source and the likelyhood of failed exhaust manifolds and the rain was too coincidental.

I was wrong.

I am now in the middle of re-doing all I have done upon discovering yet another hydro-lock scenanio. and again, pulling the plugs, draining the oil, etc...

Lesson learned.

So now I tackle the exhaust manifolds that I ignored earlier. I took the manifolds, extensions, and elbow risers off the boat, but no real smoking gun evidence to tell me that in fact I had a leak there besides the evidence of water in the piston cylinder. I've never done this before so I could be missing evidence that is right in front of me.

I'm attaching photos of the manifolds, and elbows.

PS: one reason I wrote them off as good was that the seller had handed me a receipt from a dealer that he paid to maintenance the motor (pre-sale) and in that receipt the exhaust gaskets were replaced. and that was 1 year ago, so I thought no way.

I was wrong.

The elbows had a lot of rust at the bellows connection, and I had thought that in and of itself, that was not a smoking gun since at that point in the exhaust, the water is flowing down and out.

I found no holes and no hard evidence that gaskets had failed. then again, how else does water get into the motor... only 2 ways, carb, or exhaust.

So now its a question of what to replace. the elbows? that'd be great since its not the manifolds which are more expensive. If I have to, is a complete kit the way to go?

Thank You.

 

[Bt Doctur]

You need to remove the extention block to check the manifold surface but i see no wetness or rusing to indicate a manifold/riser failure.
If the engine block is still full you would see wetness in a exaust port if it was a head issue. so do a compression test with the manifolds off and report the results

 

[MAW31]

ok. I'll test compression tomorrow. The motor ran fine with no apparant loss of power or hard starting when last i turned it off.

Also, I think almost every piston cylinder had water in it that flowed out when spark plug was removed. both sides of the motor.
That was more than when first I discovered the hydro-lock.

 

[MAW31]

ok, so I replaced the elbows/risers with new ones and new gaskets. Guess what, motor still hydro locks. looks like i'm looking for new manifolds now.

Question: What are the maximum number of conditions where water intrusion can occur to cause hydro lock?
1. bad riser
2. bad manifold
3. bad gaskets

after that, anything?

I've replaced risers and gaskets, and honestly, was a little disgruntled that there was no 'smoking gun' in the inspection of the risers and manifolds that I had, but i replaced the risers anyway because there was a good bit of rust on the bellows exit manifold side. but no holes or evidence of one, like rust marks inside the exhaust area.

and I hate replacing things just for the sake of replacing because I cant think of anything else it could be.

please help me.

 

[Bondo]

Ayuh,.... Cracks in the heads, or intake manifold,....

Drain, 'n isolate the block, 'n pressure test with air,....

 

[Lou C]

Don't forget you can also get a hydrolock from a rotted out intake manifold. Drsin the block down and remove the thermo housing and look inside with a bright LED flashlight. See if you see any suspicious areas. I had water in a cyl(actually the front 2 on my 4.3) but not enough to hydrolock it. Turned out to be blown head gaskets on both sides from an overheat several years earlier. I was able to save it by drsining the block and fogging it, cranking it and then fogging it again. BTW I had near normal comp test results; the cause was found by modifying the cooling system to allow me to see if combustion gasses were getting into the cooling water and watching for bubbles after I shut it off. Sure enough that told the tale. Obvious when I took off the heads.

 

[Rick Stephens]

Also can be missing exhaust shutters. When you pull the boat out on the lift does the stern drop at first? Might it go low enough to flood the manifolds?

Another way to check the manifolds, cap off the water pipe inlet, set the manifold level and fill the water jacket with acetone through the outer passage at the top. It will leak right through any cracks.

 

[Lou C]

I could be wrong, but those manifolds do not look like they were the source said of the water. There are no rust trails inside the center exhaust gas passage of the manifold which is what you will have to look for if the riser/manifold joints leaked.
I would expect to see some rust in the exhaust ports of the manifolds due to the water in the cyls.

 

[Lou C]

You may be having a similar issue to what I had last summer:
​had a bad overheat in 2013. Checked engine over, surprisingly normal comp test readings, no water in oil, etc. Ran fine for '14 and '15 seasons. End of '16 would not start one day. Not hydro locked, just reluctant to start. Did not know it was water in cyls. Had boat on a salt water mooring, checked fuel, igniton, then removed plugs, saw the tell tale orange color in the center insulator. Cranked engine over and water shot out of #2, and #1 seemed a bit damp, but the engine spun easily. Once I knew what the deal was, I quickly fogged it, ran it and fogged it again, and then drained the block and manifolds not knowing what was causing the issue. Got it towed in. Ran it on the water hose after blowing out water, removed manifold on suspect side, replaced with known good one, but same issue. What would happen is I would not get water in the cyl right away. It would take a day or so to leak down, then there would be water. And again, not enough to hydro lock. Has water in the oil, changed several times. Did comp test, normal. Wondering about a cracked head, rotted out intake, etc. Then rigged up a way to see if hot combustion gases were getting in the coolant. What I did:
​got a spare thermos housing, removed thermostat. Then rigged up two hoses to the nipples that feed the exhaust manifolds. Taped them together with duct tape so they are pointing straight up. Installed on engine. Put funnels in each hose filled them with water so cooling sys is 100% full. Then ran engine just long enough (while monitoring exhaust mani temp to make sure they did not overheat) to heat up engine to about 175*. Shut off. After about 2-3 min, bubbles appeared in the water in the funnels. This meant to me that there most likely was either a crack in the cyl head, or a head gasket leaking in a way that did not show low compression test readings, but would let water seep back into a cyl after it cooled off. Still could have a bad intake too. Well tore it all down, intake fine (good, because good ones for pre-vortecs are hard to find), both head gaskets blown, in fwd cyls. Cyls in good shape no rust thanks to rapid fog n drain. Had heads checked at machine shop, no good. Cooling ports too eroded for new head gaskets to seal, and center cyls on both had cracks in the exhaust seat, but no water in those cyls (go figure!).

​so for your situation, the only 'easy' cause and solution will be a rotted out intake water passage, or a bad intake gaskets that allow raw water into the oil. That much water, it has to be a big leak. My HGs were clearly blown but it never hydrolocked and it took maybe a full day, day and a half for water to re-appear.

I'd do a comp test, and do the test I did, but I think you're going to have to take this one apart. Its a 1995 and if used in salt all that time, could need new heads and all new gaskets, or a new intake.....

​looked again at your pix of the risers and manifolds and blew them up on my comp vs yesterday using phone. Based on what I saw, I would have replaced the risers due to the pitting in the sealing surface, but the manifolds looked good, esp for salt water use. I did not see any rust trails or suspicious corrosion that you would expect with water leaking in.

 

[MAW31]

Well, I finally got to testing compression: All cylinders read 150-180 psi. I had thought for sure that would be the smoking gun to justify tearing down the motor and replace the head gaskets, but now i'm not so sure that the problem is the head gaskets. Unless you all tell me that it could very probably still be the problem because the variance is high.

I had taken off and inspected the manifolds but they showed no evidence that I could point to (although i did not do the acetone test) and I replaced the elbows with new ones and new gaskets around.

Still, i'm getting hydro-lock.

What now?
a. replace the manifolds?
b. replace head gaskets?
c. no clue

I will add for edification sake that after replacing the risers and gaskets, the motor ran... but during throttle-up, power would break-off and i'd plow instead of getting up on a plane.

What, given what we're observing might be the most probable source of the water intrusion? I've got the day and the boat is on the lift...

 

[Bondo]

Ayuh,.... A compression test won't show cracked heads if the cracks are behind closed valves,....

Either pressure test the drained coolin' system,....
Or,...
Pull the heads, 'n bring 'em to yer local Machine Shop,....

 

[MAW31]

After reading your always informative posts, I concluded that the most telling awareness was -- if the issue is exhaust manifold based, the water would not likely appear in volumes in the oil pan. well, when I finally discovered the problem, the oil was milky as hell, so I'm leaning toward a head or intake manifold gasket as a likely culprit.

So there I went down to the dock, removed the exhaust manifolds...and...just...couldn't...start...the...teardown... What if i'm missing something? think, think, think... I'm at the point of no return on the disassembly of the motor once I start.

I"ve done this before where I surge into a project only to realize in the end that a little more inspection might have saved me a large effort.

hehe. so hear i am. lol.

it ain't gonna fix itself...

 

[Bondo]

. I'm at the point of no return on the disassembly of the motor once I start.

Which is why I'm suggestin' ya do a drained coolin' system pressure test,....
It "Tests" the seal between the motor's Water system, 'n the motor's Oil system,....
Pop the intake, 'n heads, the test can't be done, easily,...