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Old 05-02-2013, 01:58 PM   #1
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Where do I start? 1981 twin Lehman 2715s?

New boat for me. 1981 Formosa 42 "My Lady." She's in the yard about to get a new bottom job, no blisters! and a few other odds and ends. The engines ran well in the sea trial with no apparent issues but the PO only took it out 3 times in the last 5 years I think. 2750 hours on both.

I want to treat "My Lady" right so I'd like advice as to what I should do with the engines. I'm assuming I should change the oil and filters but I'm unfamiliar with the filter arrangement on these engines and I've never dealt with racors and know nothing about them yet. I've read here that it's a good idea to replace the pumps? and the heat exchangers? And probably the exhaust elbows too?

I've noticed that some have modified their filter setups for various reasons and I'd like to hear what and why's.. This boat has two 350 gallon tanks that were seriously hidden behind sound proofing and all we could see was a fairly good sized access port (?) on each of them but we didn't open them. There are no apparent fuel leaks anywhere and no smell of diesel either.

I'm 62 and as much as I'd like to just pay someone to get in there and do everything, I also want to know what everything is and where it is.

I'm hoping to leave as soon as possible from Punta Gorda, FL with my wife Victoria who started the very popular "For Women Only," post in the Welcome Mat forum a couple weeks ago. We hope to spend the year or more exploring the keys, bahamas, and ?

I've got a lot of time on the ocean in my small cuddy cabins over the years, and also returned from Cabo to LA on a friends 53' Alaskan woody 30 years ago. I also chartered a 39' mainship single screw for a week at Catalina Island and a 38' Bayliner in Puget sound for 10 days but that's all my experience in the last 10 years of being boatless.

Thanks for any and all your ideas and recommendations. like where to buy what parts at what prices.. etc..

Excited about our new adventure. Also any bottom paint recommendations before the yard starts it tomorrow? What should I expect that to cost??

Bob
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Old 05-02-2013, 02:12 PM   #2
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I would recommend you hire a competent mechanic experienced with 2715's the first time around. Take careful notes and watch closely as he changes oil and fuel filters, zincs, belts, hoses, and anything else that appears suspect. Have him install Racor 500 fuel filters for both engines upstream of the engine mounted filters...if you do not have these already. Have him show you exactly how to change those. When I first acquainted myself with the twin FL2715's on my boat, I had a very good, and knowledgable friend do the same with me looking over his shoulder. Once gained, knowledge of how to do it right the first time will save trouble and frustration for years to come. Secondly, I'd highly recommend you start a maintenance logbook for your engines (including generator if you have one). In it keep tabs on oil changes, fuel filter changes, repairs, etc. logging the engine hours at which each task was done. If the PO has done that, get hold of his log and cherish it for all its worth. It sounds as though he has not, so you're in the blind. You have little choice but to start fresh and change everything on those engines you can change. It may not be necessary, but you'll sleep better at night. And it's a cheap precaution to take in view of your cruising plans. Best of luck!
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Old 05-02-2013, 02:18 PM   #3
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Quote:
Originally Posted by Captain K View Post
I would recommend you hire a competent mechanic experienced with 2715's the first time around. Take careful notes and watch closely as he changes oil and fuel filters, zincs, belts, hoses, and anything else that appears suspect. Have him install Racor 500 fuel filters for both engines upstream of the engine mounted filters...if you do not have these already. Have him show you exactly how to change those. When I first acquainted myself with the twin FL2715's on my boat, I had a very good, and knowledgable friend do the same with me looking over his shoulder. Once gained, knowledge of how to do it right the first time will save trouble and frustration for years to come. Secondly, I'd highly recommend you start a maintenance logbook for your engines (including generator if you have one). In it keep tabs on oil changes, fuel filter changes, repairs, etc. logging the engine hours at which each task was done. If the PO has done that, get hold of his log and cherish it for all its worth. It sounds as though he has not, so you're in the blind. You have little choice but to start fresh and change everything on those engines you can change. It may not be necessary, but you'll sleep better at night. And it's a cheap precaution to take in view of your cruising plans. Best of luck!
Thanks Captain K. What should I expect to pay for a mechanic to do that? I also have a Westerbeke 7.5 kw that he should go over too.
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Old 05-02-2013, 02:41 PM   #4
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When you replace oil filters and fuel filters (if spin on type) mark engine hours and date on the outside of the filter, on the side you will see every time you cast your eyes in that direction. On the Racors, the clear bowl will tell you when things are getting dirty, or if there is any water (unless you are well off the beaten track, you won't see any water in the filter bowls). Keep a complete set of spare filters, using your spare and putting a new spare in stock whenever you do a change. Keep your spares in sealed plastic, maybe zip lock bags, so as to prevent contamination of the filters before you get to use them (don't ask).
Those hours are pretty light usage in 32 years (2750/32 = 85.9 per year) so without knowing the previous maintenance history you need to have a thorough going over by someone competent. You might want a proper "engine survey" complete with an oil analysis. You should do the oil analysis anyway. Then you have a starting point if you have any issues that cry out for serious engine work. You can get sterile sample bottles and directions at CAT, or any shop that does oil sampling. Some would argue that regular oil sampling will save you money and aggravation as time goes by, but jumping on that band wagon with 32 yr old engines might be a bit overkill.
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Old 05-02-2013, 04:03 PM   #5
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Not sure what mechanics charge in your area, but if you want to cut a deal, you might offer to pay a guy $$40-50/hour to look over your shoulder offering directions and suggestions while YOU do the actual work. That might save you a few bucks and improve the hands-on learning. The previous posters suggestions about marking the engine hours, and date on the filters when you change them is a great idea...BUT I would not let that substitute for a detailed engine log. Also, ditto on his recommendations regarding spares. One thing I would add to my previous suggestions is that you polish the fuel in your tanks. The term "polish" simply means you have an expert run your fuel through heavy duty filters until to clean it of contaminants. Basically, they'll run a tube down into your tanks to suck the fuel out, run it through a filtering system, then return it to the tanks. A boat that has run that little, and sat that long, will most likely have a great deal of crud in the fuel tanks. Cleaning them out will save you BIG headaches down the line. Your best sources in finding these services (mechanic and fuel polishing) will be your fellow boaters in the Punta Gorda area. Between there and Ft. Myers there should be a ton of them. Welcome to the asylum!
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Old 05-02-2013, 08:07 PM   #6
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By 2715 I assume you mean Ford Lehman 120. Maintaining these engines is a matter of following the service instructions in the operators manual.

* Oil change interval is 200 hours (we change every 100-150). Use the type and weight of oil specified in the manual.

* Change the oil filter at the same time as you change the lube oil. Use a good quality filter--- we use Baldwins. If your engines have the typical upside-down oil filter mount found on most FL120s there is an easy trick to avoid making an unholy mess when you remove the filter. Warm up the the engine until the filter is warm to hot to the touch. If you pull the oil out of the dipstick tube with a vane or suction pump this will make it flow easily. But before you start removing the oil from the sump, punch a few holes in the top (bottom) of the oil filter. This will break the suction or whatever in the filter and allow the oil in the filter to drain back into the sump. By the time you finish removing the sump oil the filter will have almost no oil left in it. Wrap a rag around the base (top) of the filter to absorb the little bit of oil still in it when you unscrew it and transfer it immedately to a garbage bag. No mess.

* Oil change interval for the jerk injection pump (CAV/Simms/Minemec) is 50 hours and should be adhered to religiously for reasons that take too long to explain here (again). You can find the topic covered in the archives, but the bottom line is just do it. NOTE-- Be very careful not to overtighten the drain plug in the bottom of the pump. The pump body is pretty soft metal and the threads can be stripped quite easily. You don't want it so loose the plug can vibrate out, but you don't want to apply too much torque or the threads can be stripped. And ALWAYS use a new compressible washer when you replace the drain plug. We use soft aluminum washers but soft copper washers work, too.

* If your engines have the original CAV cannister secondary filter setup on the rear of the engine, a very smart thing to do is ditch the cannister filter setup altogether and replace them with a pair of adapters that let you use spin-on filters in place of the pain-in-the-ass cannister filters. You'll need two adapters per engine. The stock filter holder itself with the fuel fittings and bleed screws is retained.

* Unless you know it's been recently changed, change the cooolant in the engines or have it tested to see if it's still okay. The instructions for changing the coolant are in the operators manual. Make sure you use a coolant formulated for marine diesels, not some kumbaya environmentally friendly crap like Sierra. Best bet in my and our diesel shop's view is to use Cat brand coolant. They don't make it but it's formulated to their specs for marine diesel coolant. There's stuff in it that's important for diesels to have that isn't in the environmentally friendly rubbish.

It is CRITICAL on the FL120 when you change coolant to properly bleed the air out of the exhaust manifold using the petcock at its front end. If you do not do this properly and air gets trapped in there the concentrated heat will eventually burn a hole in the manifold and these manifolds are no longer availble and haven't been for years. The only way to replace it is to scavange one off another FL120. We've made it a practice to remove the header tank cap and open that petcock until we get coolant out of it before every cold start to ensure there is no air trapped there. We remove the cap because if you don't the suction can prevent the coolant from coming up out of the petcock. (NEVER open the petcock while the engine is hot.)

* If you change the coolant take the opportunity to pre-thread one or two new drive belts onto the engine and wire-tie them to the lifting fixture on the front of the engine. The coolant hose to (or from) the header tanks passes through the belt (very bad design on Lehman's part) and so if you break a belt and don't have a replacement already pre-threaded around the coolant hose you have to remove the hose which means you dump a good portion of your coolant into the bilge. This in turn means you have to replace the coolant and bleed the system after you get the belt on and the hose threaded back through it.

* Check the zinc mounted in the main heat exchanger. This is the only zinc associated with the engine and depending on the bonding system and the current in it, it may need replaceing if you haven't done so already.

*According to people in the UK we know who know more about these engines than God, they are happiest being run in the rpm band of 1500 to 1800. Less than that and they run too cool, more than that and their longevity can be adversely affected.

* And never, ever, EVER let an FL120 overheat. Even for a minute. Nothing kills an FL120 faster than overheating. According to the people who know, the head gasket on an FL120 is relatively weak and the head is very susceptible to warping if it's overheated. So if you even suspect that an engine is staring to run hotter than normal, shut it down and finish the run on one and then get the problem checked out.

This has been stressed so much to us over the years by acquaintenances here and in the UK with a lot of experience with these engines that we have for years now used a little oven timer at the helm set to countdown five minutes and then beep at us. This is to remind us to check the engine gauges as it's very easy to get distracted. So we check the gauges, tap the button, and the timer counts down another five minutes. This has enabled us to notice the start of a temperature increase on one engine long before it became an issue. We shut it down, came home on the other one, and the problem turned out to be a partially blocked raw water throughull.

The FL120 is supposed to have oil pressure and overheat alarms on them. We don't trust them any farther than we can spit. We've found that the only dependable function of an engine alarm is to tell you that the component it is monitoring has just destroyed itself. Sort of like fuses. Electronics are designed to fail first to protect the fuses in the line, right?

There's a bunch of other stuff but those are the basics. In short, follow the service and maintenance instructions in the manual.
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Old 05-03-2013, 06:26 AM   #7
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After all the belts , hoses and mechanical work is done , the big hassle you might have is a filthy fuel tank.

Your heat exchangers should be rodded , cleaned out with a dowel and new end gaskets installed if they are of the round style .

IF "stuff" has grown on the tank walls of the tank the solutions are not easy.

Simplest is a set of Raycor 1000 or similar filters that can simply be switched as one plugs up the filter can be changed easily .This may require a quick shutdown and a small DC pump to fill the filter.

Best of course if gravity can do the trick.

A shake down where the boat is rolled and bounced for half day will be a great teacher and problem illuminiator.

Second choice is to fit a clean out in the tank, messy but really the only solution. Tank clean outs are OTS for instalation.

Having the fuel "polished" will clean the existing fuel, but the problem is the gunk on the tank walls ,so it is not a solution.


I would go with the filter bank, as it will save you loads of grief over the years , and see how long a case of replacement filters last.

You can always modify the tank if its required.

"ditch the cannister filter setup altogether and replace them with a pair of adapters that let you use spin-on filters in place of the pain-in-the-ass cannister filters. "

Great , but you will need a supply of diesel in a can to fill the canisters before you stick them up.

Many folks will use ATF as its cheap and in a quart container with a screw cap.

A ride outside in the Gulf ,when its blowing 25K to shake rattle and roll for a 1/2 day will help find problems while you are close to a solution source.
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Old 05-03-2013, 03:57 PM   #8
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If you don't have it already, you might call the Smiths at American Diesel, 804-435-3107 and ask for their "New Lehman Owner's Information" packet. They are very helpful and willing to discuss care and feeding of your engines, including maintenance schedules and spares lists, and how to check some areas like the exhaust elbow.
Additional items include torquing the head bolts, valve adjustment, motor mount replacement, shaft alignment, new oil and trans coolers, pressure-test the main heat exchangers, and replace the impellers.
Marin has posted on replacing the Jabsco pumps with Johnsons and can probably jump back in with that info, and a set of cooling hoses is always a comforting spare to carry if you don't replace them all.
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Old 05-03-2013, 04:14 PM   #9
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According to Bob Smith, who designed it when he worked at Lehman, the Lehman drive coupler that turns the Jabsco raw water pump has a finite life due to a fatal flow in the drive tang. It will eventually crack and then break. When it does the raw water pump stops right now and the engine will quickly overheat if it's not shut down immediately.

The Lehman drive coupler, Bob told me some years ago, was the only Lehman component in their marinization kit to have had a factory recall. This was for some other problem, but Bob used it to emphasize that, while everyone thought it was good design at the time, it's not. It also proved extremely difficult to manufacture, according to him, and this led to a number of problems early on.

Anyway, when the drive tang fails it cannot be repaired successfully. Bob said shops try to reweld the tang and this repair will last for awhile but not very long. The drive couplers have not been available for many years so it cannot be replaced or rebuilt unless one salvages another coupler from another FL120. And it will still have the "time bomb" in the form of the drive tang.

Fortunately the cure is very simple-- ditch the Lehman drive coupler and the Jabsco pump altogether and replace the whole deal with a new, direct-drive Johnson pump, which is what we did when it was discovered in the process of fixing something else that the drive tang on the coupler on our port engine was cracking.

Your diesel shop or American diesel will know which model Johnson pump to use.
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Old 05-03-2013, 05:03 PM   #10
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I would suggest getting hold of a copy of "Marine diesel engines" by Nigel Calder, it's available from Amazon, It really is a mine of useful information which explains how a diesel engine works from A to Z, maintenance, troubleshooting and repair.
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