Inspecting/reviving 2-year dormant lehman 120 (locked up?)

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Veteran Member
Aug 7, 2023
Going to look at a trawler this morning at 9:00. Owner paid boat mechanic to look at the engines yesterday it appears that the engines would not crank over with the starter and they were unable to turn the engine over with a "pipe on a crescent wrench" engines have been sitting approximately 2 years. I suspect Pistons are stuck in the bore due to condensation causing a little bit of rust where the rings touch the bore. I'm going to pick up a borescope and pull a couple of injectors and look inside. After confirming that engines are indeed locked up.

any thoughts/suggestions on what else might cause a dormant Lehman 120 to lock up? Mechanic States the oil looks good coolant looks good belts hoses everything like that looks like this was a running engine. Mechanic also expected the engines to just start with simple procedures and was surprised when it didn't.

any other thoughts that might be the cause?

suggestions for any tests that I could do short of pulling the damn head off that I could just do in a couple hours with the basic hand tools.?

any thoughts/suggestions and or judgments of my sanity, reasonableness of buying these engines and with the hope to get them back in service by just sending some oil and solvent down the cylinders and trying to loosen up the engines.

I am a reasonably competent mechanic. If I had more time I would totally be tearing into these engines considerably further before making a decision but I've only got a few hours today before I make the 8-hour drive back home after looking at these engines so any insight is greatly appreciated

I know over the years I personally have heard many stories in person and certainly read many stories online in similar forms of similar things happening to diesel engines and a little bit of diligence in lubricating and forced to free them up I've heard many success stories of getting engines back in service and running a long time without even having to pull the head off.

Anybody wager a guess as to the percentage chance of success? is this a 10% chance of success or is this a 90% chance of success?

The boat is and has been located in the Pacific Northwest greater Puget sound area on the water so definitely high humidity and cooler temps which leads me to the possibility of internal resting of the cylinders
I don't understand why you would want to work for free on someone else's boat when the best possible outcome would be for you to pay more for the boat.

He already paid a mechanic to determine that the motors are locked. Accept that fact and if you like the rest of the boat make an offer based on both motors needing to be rebuilt. If you get lucky once you've bought the boat, count your blessings and be happy.
Do not worry about the F.L. being stuck, not a big deal. No permanent damage done unless you try to force it with a huge breaker bar.

Remove the injectors and flood every cylinder with a 50/50 mixture of J,B, Blaster and automatic transmission fluid. let it sit for a couple days and then use a modest breaker bar on the front of the engine. If you don't get good results, top off each cylinder with more 50/50 mix and give it a couple more days. When it finally moves, put a rag over each cylinder and rotate until it moves fairly easily.

Then change the oil and replace the injectors and fire it up.

Tell the seller a new engine will cost in the neighborhood of $20,000 and get a solid discount on the selling price

Good Luck, it WILL work.

The question of "why" I might do this is not why I came here seeking input.

I'm curious as to others experiences whether it be word of mouth or personal experience on getting a lightly locked up engine back into service I've heard tons of second hand and third hand stories of this being done successfully never personally done it myself so I'm curious if somebody has some reasonable input on the question at hand maybe I'm getting paid to inspect the boat maybe I'm getting paid to take the boat away and I'm just looking at the physical possibility of getting these engines back into service I'm already fully prepared to tear the whole things down in the boat and rebuild them so if anybody has actual knowledge or reasonable second-hand knowledge of the likelihood of these engines just being lightly locked up due to some rust and being able to free them up and get them going I'd really appreciate to hear it.

And if I do take on this project I will go ahead and document it so that in the future other people that come across the same issue that I have just come across will have documentation to go back and see what it turned out to be
Thank you Pete I've heard many stories like that and that's the general direction that I was planning to go if I don't find anything else drastically wrong with the engines or drastically wrong with the boat when I actually lay eyes on it

Just out of curiosity have you personally had this happen with you on an engine that you've laid hands on or just heard from a friend

And yes there is already a lot of steep discounts involved in this engine boat combination

Thank you
I delivered my previous boat to the lift for the boat yard to do some work. When they launched I got the call that one of two engines was seized.
Long story short, I did not believe the engine was the problem, pulled the tranny and replaced the damper. The springs had fallen apart and once the engine was shut down wedge between block and damper and froze the engine unknown until my diagnosis.
I think being unable to move both engines using a pipe on a crescent wrench does not sound “lightly” locked up to me. If indeed the bores are rusted due to sitting it’s all a matter of degree. How rusted? Looking into the bores will certainly give a much better perspective of what’s going on. If indeed the bores are rusted, even rather lightly, I would argue that even getting them free they will never be in “good” shape. Consider that some of the pistons will be far down in the bores, then that entire bore could be rusty. On the other hand, it may just be one or 2 bores that happened to have a valve open that have the rust and the others could be completely fine.

Yes not sure I said that but this is a twin engine

Also I would agree that a pipe on a crescent wrench might indicate an engine more than likely locked up but I question the competence of a "professional boat mechanic" that's charging $120 an hour that didn't bring the right tools and has to resort to a crescent wrench and a scavenged piece of pipe?

It does seem suspicious that both engines appear to have locked up but for all I know both transmissions could be in gear the current owner is not a boat person bought it strictly for a living board and the person before him was a liveaboard only so it's a couple owners back before this trawler was used as a boat.
Almost all or even all transmissions connected to Lehman’s are hydraulically actuated. So no engine running, no in gear and even if mechanical and in gear engine should should be able to be turned with a bar.

If the last couple of owners were liveaboard only, perhaps it’s been longer than 2 years that the engines were used….

If both engines are locked then my previous post may not apply, as what are the odds bothe lock up from shrapnel. Now I have to wonder if the both engines were overheated and then shut down.
This is a common problem when seawater ingested, for whatever causes. For the OP, do you have honest history on the vessel?
Seems to me that it's pointless to speculate until you've seen the inside of the cylinders. If it were me, I wouldn't be trying to bar it over before examining the cylinders. Don't want to get between an owner and a broken engine. As already mentioned, soaking the cylinders of a stuck engine with your lubricant of choice generally can't hurt and may be the difference between breaking it free versus breaking it.

Any ring to cylinder lock causes some damage. After freeing, the engine may run ok, but will have a shorter life. It may smoke, burn oil, and leave a sheen. It may not.
SW Oregon on the coast is damp. It could be just one cylinder in each engine left open to the elements.

But as long as the price reflects the need for an rebuild sooner rather than later and you're ok with the effort, then it may be an ok boat.
My experience is that people that buy boats with a bad engine, spend more than just buying a boat that runs.
The engines shouldn't lock in 2 years. That part of the story smells. I've started many diesels that sat for as long as 20 years (in mothballed ships) without locking.

My current boat sat for 6 years when I bought it. 2 mains, 2 generators, none locked. Even the fuel burned.
If you are looking for a bargain, you might have one in front of you. Buy the boat based on engines that need to be replace, i.e. a deep discount. The gamble is that you will be able to get the engines going again with minimal cost. But it's definitely a gamble.

The one thing I WOULD check is the exhaust to see if there are signs of salt water intrusion. If there is, then I think it likely has two crap engines and unlikely to be bargain at any price. If the exhaust looks dry, then a reasonable chance the engines are just lightly stuck and revivable.

This reminds me of a car I bought it college with little to no money in my pocket. It was dead in the parking lot and had been loosely diagnosed as needing a head job. I checked it out, and although it wouldn't start, mechanically the engine seemed fine. So I bought it where it stood for about 1/4 it's value. I came back later that day with 4 spark plugs, and 15 minutes later drove it away and subsequently put almost 200,000 miles on it.
First thing I'd do is pull the injectors and then try to bar it over. Did they try to turn it both ways?May be a simple hydraulic bind from a leaking injector & It will turn the other way, relieve it
Good luck, my 135 in Phelps Sat for *10* yrs with water 1,/2 way up & started
First thing I'd do is pull the injectors and then try to bar it over. Did they try to turn it both ways?May be a simple hydraulic bind from a leaking injector & It will turn the other way, relieve it
Good luck, my 135 in Phelps Sat for *10* yrs with water 1,/2 way up & started
However, being that it is the same for both engines, they likely won't both have
a leaking injector causing it...
To answer your question.. YES, I have used the 50/50 mixture I suggested on a "stuck" engine. It happened to be a gasser (Small block chev 350). Thats why I know it will work. Thats how I learned to cover the injector (spark plug) holes. As the engine gets looser it will spit the 50/50 mix all over everything, very messy.

FYI. The engine will smoke like a banshee for a while until the rings re seat and all the 50/50 you put in there burns off. It may take as long as a couple hours of run time to have the smoking stop. Get it up to temp and just run it. A load is good. Vary the engine speed occasionally, from a high idle to nearly W.O.T.

Personally, I think a stuck gas engine will be stuck tighter than a diesel. They tend to run hotter, generally gassers will run a bit cleaner.

Having two stuck engines is very unusual. Can the seller provide any history on the engines?

Go for it and let us know how it works out.

I'd pull the starter and disconnect the transmission and maybe even the dampener before I decided the problem is in the cylinders. Pull the alternator while at it.

If the gear or starter is locked up, nothing will turn.

Also, pull the injectors. Are they rusty?

If a "mechanic" decided the problem is I'm the cylinders and the starter, transmission, injectors, and exhaust (and head) are still in place, the mechanic must be a magician.

There may be more to the story...but this isn't a diagnosis that is made purely based upon "can't turn over". There are just too many reasons for that.

I'm always too much of an optimist, but if both are locked I'd be more inclined to think environment in the engine room and rusty starters. But, don't trust me on those odds....w.r.t. the crystal ball department, my track record is mixed
Since you don't own the boat, I agree with earlier advice about not helping fix the seller's boat so he can sell it for more $$.

You are looking at a boat that doesn't run with potentially severe engine damage to both engines. As such it's price should be very deeply discounted. I think the question is whether you want to take advantage of that situation, including taking the risk that the engines are indeed badly damage, not just stuck in a recoverable way.

Otherwise the seller needs to figure out and fix the boat. I would not dig into someone else's boat - remember, if you break it, it's yours to then fix.

You have gotten a bunch of good advice for how to proceed AFTER you buy the boat, if you choose to go down that path. But there is no way I'd help fix the boat in it's current state to help the seller get full price for it.

If you aren't up for the risk and the project, move on to other boats.
Speaking of moving on, the red hulled DeFever 41 for sale on an active TF thread is a good example of vessels that deserve a first look, beyond internet shopping.
OP asked what were the odds of him being able to unlock the engines. Unfortunately, it’s an impossible question to answer. Right off, several very smart TF’s suspect there is more to the story and have genuine fear that there is a major issue at play. It’s just odd that both engines are locked after two years.

If just one engine was stuck I would give you a 90% chance of success by either breaking loose surface rust or finding fluid in a cylinder.

With both engines stuck I give you a 90% chance that you have been lied to and these engines are in serious trouble.

OP, go in with your eyes wide open.

In my experience boats that are used only as cheap housing were already in trouble and that is how they became cheap housing.
Well it's officially my headache now...

Started removing injectors so that I could spray them up with lube and do that whole game was very pleased when I removed the valve cover the casting was very clean no Gunk no sludge or anything like that all the injectors came out nothing scary yet

but on the port engine it's another story

Upon removal of the valve cover I could see rust residue where water had pooled. But only where you could see there had been a small puddle most everything else rocker arms pushrods all that sort of stuff didn't have any rust on it


Everything went okay pulling the injectors until I pulled the last injector from the number six cylinder and got a geyser of water for a couple of seconds cylinders completely full of water no indication of rust on the injector tip the water is clear and it was hard to get a sample of water that didn't have oil floating on it but it I suspect it's salty the engine coolant is green in color and this is definitely water in the cylinder

I'm curious as to where the water may have come from especially since it's probably been in there or at least the claim that it has been sitting for years I would have thought the water would have been Rusty and murky and nasty but it's not what could the source of the water be a rusted out exhaust manifold raw water rusted through or something like that I'm tracking down something now to be able to get all the water out of the cylinder and get lubricant down in there looking forward to any of y'all's thoughts or suggestions
Well...if it isn't coolant the likely sources are the exhaust or the oil cooler.

It could be from a leak or from someone, perhaps somewhat recently, turning it over without it starting and getting it flooded with salt water that way.

I'd get a sample and check it with a refractometer to see if it is salty. It could also be that someone was working on the water-in-oil problem and was running with water while debugging the leak and then topped it with fresh coolant, perhaps recently, to sell. You can save some water now and order the refractometer from Amazon and test it when it shows up -- takes just a drop or few. I'm not saying I suspect this, just that I'd want to test because, in the unlikely case it is freshwater, that'd save a lot of time down the wrong trail.
Not sure I understand how a failed oil cooler could fill a cylinder with water? Am I missing something?

I would think that could get water into the oil or oil into the water but how would it get into the cylinder?

Oil on the dipstick looks reasonably clean and appropriately full. I have not drained the oil yet. so I don't know if there's any water settled to the bottom.

Headed back to the boat shortly see if I can figure out if it's fresh water or saltwater pretty certain it's got to be salt water

Well the history of the boat is vague and some may consider sketchy the owner the legal owner that I just bought it from was the marina they had taken it in lieu of delinquent slip fees about two and a half years ago they then sold it to somebody on terms who kept it for a year and a half and then backed out they took the boat the marina took the boat back another person bought it 6 months ago again on terms from the marina with the intent to fix it up just as a liver board he bailed out and it was for sale the most recent I guess I'll call him a tenant I was able to speak with he claimed he had never tried to start the engines and right before I came up to view it he paid the mechanic to come out and look at it and try and get it started so I don't think he had done it previously and he certainly wasn't expecting it to be locked up cuz my bringing the mechanic out and finding out that it was locked up that just made it easier for me to negotiate down but it is definitely not the best conditions to buy a boat but I was happy with the price even if I have to rebuild the engines I'll be satisfied my main goal now is to get the water out of the cylinder and make sure that it doesn't deteriorate any further before I depart for a couple of weeks before I can come back and take the next step
Yeah I'm pretty happy with the deal of course I'd be a lot happier if I can get these engines running without having to rebuild them completely right away...

Heading back with the borescope rental right now hope it fits through the injector hole might have some more news about at least 11 cylinders the one that's full of water I still haven't figured out what I'm going to do with...
Do the engines have water lift mufflers?

Maybe post a few pictures of the exhaust system on each engine?
Yes, pretty sure they are water lift muffs. Tried to post pix previously but was unable.
Not sure I understand how a failed oil cooler could fill a cylinder with water? Am I missing something?

The only way that would have happened is if the water entered via oil cooler, foamed or became emulsified, and then demulsified or separated later on, settling to the bottom of the pan and the bottom of the cylinder. It is /very/ hard for me to imagine such a thing at anywhere near the scale you describe.

But, if it isn't coming via the exhaust (either via a leak, or by being turned over and thereby being pumped in, or by being pushed in by wave/water action and then pumped in by turning over), and it truly isn't coolant or freshwater from the closed cooling loop (which is why I suggested definitive testing), it has to be something...and that was the only other thing I could come up with at that moment.

I've now thought up with one other possibility...water coming in the air intake via some type of flooding.

Also, now that you mention not finding any via the dipstick, if you are right that there isn't much in the pan (just, perhaps, a little at the very bottom), that does point pretty clearly toward it coming in via the exhaust oen way or another.

Happy hunting!
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