2010 MoM rebuilt engine suddenly won't turn over

[denesszabo]

Dear A4ers,

I am new to the forum, this is my first post. I am on a cruise from Florida to Maine and back (we are in Gloucester,MA at the moment) with my family and our (so far) trusty A4 suddenly stopped working.
We own a custom built 1975 IOR 3/4 Ton sailboat. She has an Atomic 4 with a V-drive. The A4 is a relatively recent (installed either in 2009 or 2010) rebuilt engine from Moyer Marine with all the possible options (fwc, electric fuel pump, etc.) The engine has always started right up and ran like a clockwork until 1 month ago. One morning in Tenants Harbour, ME the engine refused to start. When I turned the ignition I heard the loud click from the starter, but then nothing happened. A closer inspection showed that the propeller was not fouled (turned freely in neutral), there was sufficient power (also tried a second fully charged battery) to the starter and it engaged, but the flywheel did not turn at all. Since that day I did all the possible tests I could think of (removing the spark plugs to check for water in the cylinders, removing the starter to have access to the flywheel and tried to turn it with a big screwdriver, etc). It seems that the engine is stuck, and it will not turn over. The flywheel does not move AT ALL. When the started engages it is like hitting a wall. I discussed the issue with two mechanics, and both suggested independently that there is some internal failure in the engine and it must come out of the boat (access is VERY limited) and disassembled. So before I make a major decision to remove and fix/replace the engine here are my questions to the experts:

- Are there any other tests that I could carry out to locate the possible cause why the engine does not turn over?

- What is the most probable cause? One mechanic suggested a broken crakshaft...

- What is the best place to get the engine fixed along the East coast South of Boston?

- Should I undertake the disassembly of the engine myself, or pay a mechanic, or get a rebuilt engine from MoM? When I inquired about the price of removing the engine, disassembling it, getting the parts etc. in a boatyard, they said I might be better off by getting a rebuilt engine from MoM and simply swap the two. I am wondering how difficult it would be to do the work myself. I am certainly not a mechanic, but I undertook some engine work before (mostly on my cars and diesel engines in my sailboats). Usually tasks with medium difficulty like rebuilding a water pump, overhauling the hydraulic system of an old Citroen, etc. I never removed the head of an engine before. On the other hand I don't have much to loose. If I mess it up, I can still get a rebuilt MoM engine. I have the MoM overhaul manual and it seems pretty detailed.

Sorry for the long post and as usual I appreciate your input.

Have a good day ,
Denes

[Dave Neptune]

First welcome to the MMI Forum. Those mechanics are full of green cheese.
Did you do a lot of cranking at any time prior with the water valve left open? If so did the engine run the last time before it would not start(?) correct? Were there any signs of moisture on the plugs?

I think your rings are just stuck, not to uncommon. Toss some spray oil in the cylinders and let it sit for a bit. If you have access to the flywheel teeth you can use a big screwdriver or a small crowbar and work the rings free. If you do not have access up front just pull the starter and that hole works very well. Just pry back and for the gently at first and steadily increase the pressure working in BOTH directions. Once you have any movement your home free.

Any broken internals that would cause an engine to seize would have to of been a catastrophic "blow up" at high RPM's~I think you would of noticed that.

Also a breech of the intake manifold can allow water to get into the cylinders and cause the rings to stick as well.

First get it freed up or at least soaking a bit. We can diagnose the problem later.

A broken crank would wiggle at both ends just not both at the same time, That is how I have tested for broken cranks in the field~usually a "hot boat".

Dave Neptune

[Mo]

Good post Dave. I agree that water somehow may have gotten into the top end and sat there for while. I'd too would spray some penetrating oil in the spark plug holes and spray around the valves as well as they probably could use a shot as well. I'd leave the plugs out while trying to pry the teeth of the flywheel...less compression and should make it easier.

How long since the engine last turned over?

[denesszabo]

Dear Dave,

Thanks for your quick reply. I have been reading the forum before to learn as much as possible about the A4. When you are out cruising you can be sure that the time comes when something goes wrong with your engine. So better be prepared...
To answer your questions: No, I did not cranck the engine before the seizure. It always just started immediately up, never needed cranking. It ran perfectly well before the seizure including the last time. I just ran it for maybe 30 minutes to enter Rockland Harbour then shut her down as usual. I did not notice anything out of the ordinary, no rev-up, nothing.
When I removed the plugs there was absolutely no sign of moisture on them. I peered into the cylinders with a mirror (not much space above the engine) and could not see any water in them.

I already added some Marvel mystery oil to the cylinders and let it sit for a day, but there was no result. I have no access to the flywheel (I cannot remove the cover because the fresh water pump is in the way), but I already did what you suggested: I removed the starter and used the hole to put a big screwdriver between the teeth and tried to move the flywheel by prying with my full strength, but no go. It did not move. Although I only tried to move it in the normal (counterclockwise) direction. Maybe I should try to move it in the opposite direction too.

The mechanic who suggested the broken crankshaft said something that when the crankshaft breaks the uneven failure surface will result in one half of the shaft pushed forward and the other half pushed backward when the shaft starts to rotate, so it gets completely stuck. He also said thet this should only happen if I accidentally rev the engine up. But this did not happen, rev on this engine has never been above 2000 rpm.

Thank you for your input and I am looking forward to your further ideas how to free the rings if it is indeed the rings that are stucked. I read in another post in the forum that the flywheel should still wiggle a little bit back and for when the rings are stuck. Isn't this correct? My flywheel does not move at all.

Best regards,
Denes

[denesszabo]

Dear Mo,

Thank you for your reply.
When I tried to pry the flywheel I left the plugs out to have less compression. What works best as a penetrating oil in the cylinders?
The engine sit 3 days between the last time it ran and the time when it did not start.

Thanks,
Denes

[joe_db]

50/50 mix of ATF fluid and acetone might work.
Also Marvel Mystery Oil.

[Dave Neptune]

Go both ways, not just one!!!!! BACK AND FORTH AND BACK AND FORTH. In fact a light strike on the pry bar when loaded up in each direction may help, just not to hard at first and GO BACK AND FORTH to create a gap!!!

You should see some movement of the flywheel teeth when going back and forth just from the clearance in the bearings!

Did the oil level go up or is it milky looking?

Dave Neptune

[denesszabo]

Dear Dave and others who took the time and helped me with your advice.
I do not know how to express my gratitude. The engine is up and running again!
It took only 1 hour. I poured mystery oil into the cylinders last evening and let it sit overnight. In the morning I tried to pry the flywheel, this time to the opposite (clockwise) direction. After 5 minutes I could move it a couple of inches, and after 15 minutes I could turn the flywheel around with hand... I then reinstalled the plugs and the starter and voila. It started right up. I kept it running for 20 minutes, everything seemed normal.
I am still not sure how the rings got stucked. There was absolutely no moisture on the plugs, the oil is clear. I wonder what should I do to prevent this to happen in the future. Any ideas?
The oil pressure is around 20, and I think it should be a bit higher, but 20 should still give plenty of lubrication to the rings, is that true?

Thank you very very much again for your help. Next time I have an issue I will first browse the forum (I found that Dave gave this same advice a countless times on the forum before; he might be quite tired of repeating it to dumb people like me...), then ask my question from the forum, then go to a mechanic.

Have a good day,
Denes

[Marian Claire]

When is the oil pressure 20? Cold/totally warm, idle or cruise RPM.
Do you use any MMO in your gas?
Dan S/V Marian Claire

[Dave Neptune]

Denes, the oil pressure has nothing to do with oiling the rings as they mostly "splash oil".
About the only thing to stick the rings is water from somewhere. The culprits are as follows and not in any order of likelihood:

Stuck ant-syphon valve~allows water to be sucked into the exhaust and then into an open exhaust valve to the rings.

Manifold breech~a hole in the cooling jacket of the intake/exhaust manifold can get water into the cylinders and to the rings.

Excessive cranking with the water valve open~allows water to build up in the exhaust and run into the manifold and to the cylinders and rings.

A breech in the head gasket.

A breech in the bottom of a cylinder due to rusting through.

Any of the above can get water into the cylinders and it does not take much at all!!!!
Keep a close check on your oil for milkyness or an increase in oil level. Also you can check under the oil fill cap for moisture collecting there, this will let you know that water or moisture is encroaching.

Dave Neptune

[denesszabo]

Hi everyone,

I thought I would give an update on the status of my engine which got stuck (seized) in the middle of a cruise in Maine. The engine and the boat are now winterized and hauled for the winter.
With the help of Dave and others from the forum I managed to free the engine by turning it in the opposite to the normal direction. Since then, we ran the engine approximately 30 hours with (almost) no problem. We crossed the Cape Cod canal and the East river under power.
Dave suggested that water in the cylinder is the most probable cause of the seizure. I changed the oil twice and removed the spark plugs at least a dozen times, but I was unable to find any trace of water. What I noticed, however, is that since the seizure there is a metallic ticking sound coming from the motor block, and one spark plug (2nd from the flywheel) is always covered with a thick layer of black dry soot. The ticking is not always there, sometimes hardly audible, sometimes very loud. It always becomes louder with higher rpm.
After reading posts of the forum I think there is probably a broken valve spring. Do you guys agree? I will have to check this in the spring.
I was also wondering whether the seizure could be caused by the broken spring, which might got stuck somehow somewhere preventing the engine from turning over. It would also explain why it was relatively easy to free the engine by simply turning it in the opposite direction which probably freed the broken spring from the stuck position.

Best,
Den

[Dave Neptune]

Den, the valve spring would not cause the seizure.

RE the sooty plug, do check to be sure the choke is opening, The #2 could well be the culprit that got stuck so it could well be that the ring(s) could also be stuck in the piston now~~again no biggie yet. I do not no if you use any fuel additives~~do you? If you do use MMO in the fuel do you know how much you added to give a ratio?

Do a compression check on #2 first dry and then wet by adding or preferably spraying some oil into the cylinder and get back if you can.

I would recommend that you get to a marine store and buy a small bottle of synthetic 2 stroke oil or the best they have like OMC, Mercury, Yamaha etc. Then calculate via how much fuel you have in the tank and bring the total (including the MMO already possibly there) ratio to approximately 100:1 or even a bit richer. Also open the gap on the fouling plug to about .045 and/or rotate in a new hotter plug in that cylinder and set the gap to .045 on the plug(s) your rotate in. Run her for a while a few times checking THAT plug for color and cleaning it before reinstalling or just rotate another in and go. Watch for a changing of "color" to dark gray or lighter and that means the ring is coming loose and reseating~a good thing.

The missing of #2 could well be your noise as the slight miss can cause a shutter or shake in the engine.

Dave Neptune

[denesszabo]

Dave,
Thanks for your reply.
To answer your questions:
I did not particularly looked if the choke opens (It worked fine when I removed, cleaned and reinstalled the carburator in 2014), but at least it operates as it should. The engine only starts when I use the choke in cold. It was really cold this October and November, so I had a lot of chance to start the engine with the choke open. So I think the choke works.
I don't use MMO in the fuel, only in the oil. I always add Sta-Bil marine fuel stabilizer to the gas because we hardly use a full tank of gas during one season. Can I safely mix MMO and Sta-Bil?
What is the most common reason for a sooty spark plug? I think first I should check the valve clearances, especially on #2. Could the ticking noise come from a valve that has too small gap?
Unfortunately I did not make a video of the engine noise, but it doesn't sound like a shaking or shuttering engine. It is a very prominent and sometimes loud metallic knocking sound (metal hitting metal). Sometimes it's not audible at all.
I also did not notice a loss of power. We usually cruise at 1500 rpm which corresponds to 4 knots, and that's what we also had after the seizure.
Unfortunately I am an ocean away from the boat, so I will not be able to test or do anything until the spring, but it would be nice to have a course of action prepared for the spring. So far this is what I would do:
1. Make a compression test, dry and wet. (By the way, how to extract the oil from the cylinder after I spray it in?)
2. Adjust valve clearances.
3. LAUNCH BOAT.
3. Add oil to fuel to 100:1 ratio and replace #2 plug with hotter plug with 0.045 gap. Should I replace all the plugs, or it is OK to have one different plug?
4. Use engine as usual and check plugs frequently.
5. hope for the best...

Best, Den

[sastanley]

Originally Posted by denesszabo

Dave,

I don't use MMO in the fuel, only in the oil. I always add Sta-Bil marine fuel stabilizer to the gas because we hardly use a full tank of gas during one season. Can I safely mix MMO and Sta-Bil?


Best, Den

Hi Den, In my opinion, yes. A little MMO in the gas is kinda like 2 cycle oil to lube the valves. I have run mine with some MMO on occasion. I think Dave Neptune does too..but I'll let him confirm his ratio.

The seizing engine/valve spring is still an unknown. We can guess over the winter.

Making sure the valves and springs are all correct/within clearance is a good thing.

The P.O. of my boat seized the motor more than once with rust in the #4 cylinder by flooding it during extended no-start cranking events.

You can certainly run one plug different. I did that, but did not have appreciable success..I am currently running standard Moyer recommended RJ8C's with good results. Your Mileage My Vary (YMMV)