Hydrolocked? Yanmar 4JH2-TE

[a64pilot]

Assuming it’s not an overhead cam engine, you don’t have to worry about timing at all.
Actually pulling a head on a cam in block motor is as easy as changing a tire. More steps, but not complex.
I wouldn’t even pull the manifolds unless you had to to access a bolt, I doubt you do but can’t know.

I’d let her soak a while first, then maybe after two days pull the head, but pulling the head most likely is just going to make the engine smaller and lighter to pull, cause if its seized, you can’t do much to unseize it by pulling the head, do not be tempted to put a 2x4 in there and wack away at the pistons, I’ve seen a few get busted that way, they are just cast aluminum.

[Cheechako]

Good point Geoff on if there may still be water in there.
If you remove the head and it wont turn, take a 2 x 2 wood and rap on the top of each piston using a hammer with the wood on the piston top. A little "shock" may be needed. If it hasn't been that long that should work to break the rings free from the cylinder walls.
Once free you can rotate the engine and clean up the cylinder walls with scotchbrite and oil so they dont pit.

[IsaakOker]

Originally Posted by a64pilot

Assuming it’s not an overhead cam engine, you don’t have to worry about timing at all.
Actually pulling a head on a cam in block motor is as easy as changing a tire. More steps, but not complex.
I wouldn’t even pull the manifolds unless you had to to access a bolt, I doubt you do but can’t know.

I’d let her soak a while first, then maybe after two days pull the head, but pulling the head most likely is just going to make the engine smaller and lighter to pull, cause if its seized, you can’t do much to unseize it by pulling the head, do not be tempted to put a 2x4 in there and wack away at the pistons, I’ve seen a few get busted that way, they are just cast aluminum.

OK, I'll sure wait a bit that the oil penetrates but as geoff mentioned that if there is still water sitting on the pistons I have to get rid of it first, I'm looking for a way to do that although I don't see any "bolt" or plug that seems to be a drain.

As for the OHC, I don't think it is... But I'm not 100% sure now that you mentioned it... I thought it's a single camshaft in line with the crankshaft and flywheel..

[IsaakOker]

Originally Posted by Cheechako

Good point Geoff on if there may still be water in there.
If you remove the head and it wont turn, take a 2 x 2 wood and rap on the top of each piston using a hammer with the wood on the piston top. A little "shock" may be needed. If it hasn't been that long that should work to break the rings free from the cylinder walls.
Once free you can rotate the engine and clean up the cylinder walls with scotchbrite and oil so they dont pit.

Why should it move if I take the head off? I supposed that having the head on is the same as off.. Basically unless I let oil penetrate to release the rings, they won't break free & I'm not completely convinced about banging them out.. Hahaha
I've seen mixed opinions on applying force to the pistons themselves..

But I will most likely have to take it apart in the coming days anyways..

[roverhi]

Freshwater rusting the rings to the cylinder bore in that short period of time is not common but possible in an engine that has sat for a long time and oil has drained/evaporated off the cylinder walls and rings. Rapping on the pistons will hopefully shock the rings free from the cylinder walls. You don't wail on the pistons but a few solid raps with a hefty hammer on wood should do the trick to unstick the rings.

WD40 could be the better choice to use in the cylinders if water is still their. WD stands for water displacing so might be a better choice in this case. It's a pretty crappy penetrating oil, however. Auto Transmission fluid mixed half and half with Acetone has been tested as the best penetrating lubricant.

[IsaakOker]

Originally Posted by roverhi

Freshwater rusting the rings to the cylinder bore in that short period of time is not common but possible in an engine that has sat for a long time and oil has drained/evaporated off the cylinder walls and rings. Rapping on the pistons will hopefully shock the rings free from the cylinder walls. You don't wail on the pistons but a few solid raps with a hefty hammer on wood should do the trick to unstick the rings.

WD40 could be the better choice to use in the cylinders if water is still their. WD stands for water displacing so might be a better choice in this case. It's a pretty crappy penetrating oil, however. Auto Transmission fluid mixed half and half with Acetone has been tested as the best penetrating lubricant.

That's what I would have though but yes, the engine has been sitting for ages so I suppose it was dry as I only checked the oil from the dipstick before cranking it.

Only issue is that I don't know if water is sitting on the pistons as I've filled them up with the penetrating oil..

Is there a way to drain that oil and possibly water without taking the head off?

That's the reason I asked initially about WD40 as it being water displacing I didn't think it would be all so healthy to put it in there with the pistons. But we'll, unless I can drain the Marvel oil & water I suppose there is no point to try to get anything else in there..

[IsaakOker]

I just came to the thought which I don't know if it's ridiculous but could it be that the gearbox is stuck & thereby keeping the engine from turning?

[jimbunyard]

I've read all your posts and most of the responses, but I'm still unclear about certain things.

Has the engine started, or have you just 'turned it over' with the starter, or has the crankshaft not been rotated in the 5 years that the engine has been unused?

The engine is an Overhead Valve Engine (OHV), not an overhead cam engine.

If the engine rotated 10 days ago, and is now 'locked up', something isn't kosher. The engine can't be 'hydrolocked' if you have the injectors out (unless you broke a rod or dropped a valve in the process of hydrolocking it); I can imagine no instances in which enough corrosion could form in 10 days to lock an engine. Perhaps 'lock' it enough so the starter might not turn it (though that'd be a stretch too), but not enough so that it couldn't be turned with a breaker bar.

It is extremely unlikely that anything could go wrong with the gear to lock the engine up.

Without further information, I'd go with the penetrating oil and time, and get a 2-3 foot breaker bar to put on the crank nut...

Here's a service manual

http://www.endeavourowners.com/dscsn...e%20Manual.pdf

[Geoff54]

Sorry for the confusion. The water lift muffler won't drain the cylinder but if it fills up with water, the water will back up into the exhaust system and from there into the cylinders. The exhaust from the engine goes through the mixing elbow, where it is mixed with water from the heat exchanger and then into the water lift muffler. It usually look like a round tub just behind the engine with two hoses going into the top - one inlet hose from the mixing elbow and one outlet hose which is the exhaust to the outside of the boat. There will be a drain bolt near the bottom. This will drain the muffler and the exhaust system and prevent any more water making it's way into the engine.

If you have added oil to the cylinders and there is still water present, it won't do very much. You can wait and see, in which case any corrosion will be continuing, or you can suck it all out and start again. A piece of hose down the injector hole connected to a wet-vac, mighty-vac, or almost any suction pump should do it.

Removing the cylinder head is relatively easy on this engine but if the pistons need to come out, the rod caps must be undone from the bottom. and there is never enough room under the engine - I had to pull my engine into the main cabin. Looks like you have a link to the service manual. I can also email a copy of the parts manual if you can't find it online but I won't be home for a couple of weeks.

Good luck.

[IsaakOker]

Originally Posted by jimbunyard

I've read all your posts and most of the responses, but I'm still unclear about certain things.

Has the engine started, or have you just 'turned it over' with the starter, or has the crankshaft not been rotated in the 5 years that the engine has been unused?

The engine is an Overhead Valve Engine (OHV), not an overhead cam engine.

If the engine rotated 10 days ago, and is now 'locked up', something isn't kosher. The engine can't be 'hydrolocked' if you have the injectors out (unless you broke a rod or dropped a valve in the process of hydrolocking it); I can imagine no instances in which enough corrosion could form in 10 days to lock an engine. Perhaps 'lock' it enough so the starter might not turn it (though that'd be a stretch too), but not enough so that it couldn't be turned with a breaker bar.

It is extremely unlikely that anything could go wrong with the gear to lock the engine up.

I'd go with the penetrating oil and time, and get a 2-3 foot breaker bar to put on the crank nut...

Here's a service manual

http://www.endeavourowners.com/dscsn...e%20Manual.pdf

Hii Jimbunyard!

First of all thanks for giving me your thoughts on this as I'm as confused as you are or probably even more..

Also, thanks for clarifying that is an OHV but I still thought that taking apart this engine will require quite some knowledge to get timing right when putting all back together.

So to the questions.
The boat was sitting still for 4-6yrs so I'm quite certain nobody even tried starting the engine in that time.
I came along and 2 weeks ago I got a mechanic that sadly wasn't marine (so we didn't close the thru hull) to look at the engine before I bought the boat because I had engine replacement issues on my last sailboat.
He managed to get the engine to turn over and try to start but we never got it running.

Now, I've been doing other repairs on the boat these 10-14days and wanted to take on the engine 2 days ago when I hooked up a battery to the starter and noticed the solenoid started smoking and cables getting very hot after the starter would do a "clunk" noise but nothing else.

2- then I went ahead and took the starter off the engine to test if it would engage and spin freely as I initially I thought that the battery was to weak but it didn't drop below 9.7v when trying to start the engine so I guessed that the starter was shorting out or something.
While testing the starter, it nearly melted the battery poles in those 3-5 seconds so something is wrong with it.

3-I was going to purchase a new starter and hook it up to the engine but when I started investigating I thought that maybe the starter is broken but that the engine might also have an issue and I didn't want to try to crank it any more as I was afraid to break anything.

4-I took the 4 injectors out in the hope that I could turn it over by hand before buying the new starter and having peace of mind that it won't break anything by trying to start it.

5-Here is where I'm at. An engine that didn't run in the last 5 yrs but 10 days ago did "turn over " multiple times although didn't get to run and both me and the mechanic couldn't here any harsh or suspicious noises.
The reason why we didn't try starting it any further was because the return pipe of injector 2 was corroded a bit and was leaking fuel.

I'm also very surprised that they're stuck but I'm somewhat afraid at trying to turn the crankshaft by the bolt..
I've put a 1/2" socket wrench on there and jumped on it many times but it just gets tighter without moving the crankshaft a slight bit.

[IsaakOker]

Originally Posted by Geoff54

Sorry for the confusion. The water lift muffler won't drain the cylinder but if it fills up with water, the water will back up into the exhaust system and from there into the cylinders. The exhaust from the engine goes through the mixing elbow, where it is mixed with water from the heat exchanger and then into the water lift muffler. It usually look like a round tub just behind the engine with two hoses going into the top - one inlet hose from the mixing elbow and one outlet hose which is the exhaust to the outside of the boat. There will be a drain bolt near the bottom. This will drain the muffler and the exhaust system and prevent any more water making it's way into the engine.

If you have added oil to the cylinders and there is still water present, it won't do very much. You can wait and see, in which case any corrosion will be continuing, or you can suck it all out and start again. A piece of hose down the injector hole connected to a wet-vac, mighty-vac, or almost any suction pump should do it.

Removing the cylinder head is relatively easy on this engine but if the pistons need to come out, the rod caps must be undone from the bottom. and there is never enough room under the engine - I had to pull my engine into the main cabin. Looks like you have a link to the service manual. I can also email a copy of the parts manual if you can't find it online but I won't be home for a couple of weeks.

Good luck.

OK! I guessed it was that. I actually already took of the mixing elbow yesterday as I was planning on pulling the engine out anyway to change all pipes and gaskets & inspect the elbow.
When taking it out maybe half a quart of coolant (which must have been in there these last years) came out of the heat exchanger.

I've been reading the service manual as I have it here on the table and taking of the head does indeed seem quite easy but I thought that it was hard to put back together.. Because I suppose that the rocker-arm, etc have to be timed.

I'll look for the parts manual online as I have found the cooling system parts manual pages online before.
Thank you anyways!

[Wotname]

Jimbunyard raises some good questions and as far as I can tell, the hydrolock is still only a supposition as this stage.

Another possibility is the sea water pump is "locked" and as it mechanically gear driven on the 4JH2, this would prevent the engine rotating.

Easy to check, remove it and see if the engine is now free to rotate.

I have had this problem on a Buhk. Engine sat unused for a few months and then would not rotate. The sea water had been leaking and had rusted the shaft to the bearing.

[IsaakOker]

Originally Posted by Wotname

Jimbunyard raises some good questions and as far as I can tell, the hydrolock is still only a supposition as this stage.

Another possibility is the sea water pump is "locked" and as it mechanically gear driven on the 4JH2, this would prevent the engine rotating.

Easy to check, remove it and see if the engine is now free to rotate.

I have had this problem on a Buhk. Engine sat unused for a few months and then would not rotate. The sea water had been leaking and had rusted the shaft to the bearing.

Thanks for joining too, I can't believe how many replies..

Yes, it's a supposition.
I can't move it at all, Starter motor seems to be shorting in one way or another because its a 1.4kw but can weld with the battery terminals...

So that's why I though it might have to do with the gear box blocking it.. But I'll check the pump in 1-2hours as that might be a point..
The fresh water pump spins freely now that the belt is off but I haven't chdcked the sea water one yet.

It's a supposition but we did try to start the engine 10 days back & we probably made it turn 25-50 turns without getting it started so it might well be hydrolocked.

[Wotname]

Originally Posted by IsaakOker

........
2- then I went ahead and took the starter off the engine to test if it would engage and spin freely as I initially I thought that the battery was to weak but it didn't drop below 9.7v when trying to start the engine so I guessed that the starter was shorting out or something.
While testing the starter, it nearly melted the battery poles in those 3-5 seconds so something is wrong with it.

...............

As an aside, did the starter motor actually spin when you tried testing off the engine?

I realise this is not you priority right now!

[Geoff54]

Originally Posted by IsaakOker

OK!
When taking it out maybe half a quart of coolant (which must have been in there these last years) came out of the heat exchanger.

Are you sure it was coolant or was it raw water. If it was coolant there is a problem with heat exchanger. Raw water and coolant should never meet.

Originally Posted by IsaakOker

OK!
Because I suppose that the rocker-arm, etc have to be timed.

No. When assembling, just slacken off the tappet adjusters and make sure the rocker arms ends are correctly engaged with the push rods. Then reset the clearances once you have torqued the head.