There are some intermittent phone outages occurring in our area so if you need to contact us, please send an email, facebook messenger, or leave a message and we will contact you as soon as we can. Thank you!

It’s official, the busy season is here!

Our priorities during the busy season are malfunctions and already scheduled work sorted by priority!  If you need service, please select the “Contact Us” section of this website to fill out  a service form. We typically work 2-3 weeks out during the busy time but it is best to get your work order on the books.   As usual, you can call to schedule if you prefer phone contact! Please leave a voice mail if you do not reach us directly. We will return your call just as soon as we can, in the order it was received.

Have a safe boating summer!

We have moved to 905 N. 23rd Street!


905 North 23rd St – Unit B

Next to R.A. Jeffreys Beer Distributor. Come through the gate!

Our new facility offers more room for shop space, office space, and inventory storage, in order to accommodate more of our customer’s needs &requirements.

We look forward to seeing you soon!



History of Specialized Mechanical

Specialized Mechanical Services, Inc. was started in June of 2002.  Josh Roberts, who had been the Service Manager and Mechanic Foreman for Bennett Brothers Yachts, decided he needed a change.  At that time, Jim Corse, of Corse Marine Services, was looking to retire from his business and move back to Scotland.  Jim’s  Corse Marine Services serviced sail and power boats around the Wrightsville area and were dealers for Yanmar and Westerbeke.  After a number of beers at a backyard cookout, Jim was able to talk Josh into buying his company and leaving Bennett Brothers.  Josh has never looked back.

Jim Corse gave Josh a head start by introducing Josh to his customers by way of a letter.  This allowed him to “hit the ground runnin’”.    In the early years, Josh took on all kinds of work, not just the yacht service, but other things as well.  He took care of the Cape Fear Trolley’s for a number of years, before he got too busy with yacht work.  A number of high rise fire pumps came his way along with the servicing of generators for Cinema Catering out near the MGM studio.  Now, yacht work is almost exclusively what we do at SMS.  He also worked for Custom Steel Boats in Merritt, NC on a Cape Horn 83’ exploration trawler.

One of the things that sets SMS apart from many other service companies is our customer service etiquette.   We believe that honesty IS the best policy along with integrity, doing the right thing when nobody’s looking.   We also strive to be technologically advanced, making training an important part of operation.  Our technicians annually attend seminars at Yanmar, Volvo Penta and Westerbeke facilities.

Having the knowledge and the proper tools allows our technicians to properly diagnose problems in your vessel in less time and with more accuracy.

Our customers don’t have bottomless bank accounts so we try to be as efficient as possible in performing the work.  We like to think that we spend your money as if it were “our own”.

Customers need to be kept up to date with what is going on with the repairs to their vessel and we strive to do that.  Communication is not always perfect, but we make an effort every day to make it as close as possible.

Diesel Fuel Additives

Today’s diesel fuels are not what they seem. On the one hand, the new ultra low sulfur diesel would seem to burn more completely and with less emissions that the older diesel fuel. That may be true under some conditions, but more often it actually doesn’t burn as well. Old fuel is presenting more problems than ever before. I believe that the newer fuels have a much shorter “shelf life” than older fuels, not that it was that much better before.

We are seeing more blueish smoke on start up from all brands and types of diesels. Particularly, on higher performance engines (turbocharged/intercooled) the smoke is prevalent not only at start up, but at light loads even after the engine has warmed up. What is causing the smoke is a lack of cetane. The cetane rating of a fuel is somewhat like octane is to gasoline, but inversely. In gasoline, the higher the octane, the more difficult it is to make the fuel spontaneously explode due to heat. The higher the cetane rating of diesel fuel, the easier it is for the fuel to be ignited by heat.

What this means to the engine is not so easily explained. Here goes nothing. When the piston of a diesel engine rises toward the cylinder head on it’s compression stroke, the fuel is injected slightly before it reaches the top. The fuel ideally should start to burn immediately after it is injected into the hot compressed air. If it doesn’t, two things happen. First, the fuel starts to collect in the combustion chamber until the temperature reaches it’s ignition point. When that happens, all the fuel burns at once, making a “bang” in the cylinder. This makes the engine very noisy. Second, as the fuel isn’t burning, it may come in contact with the sides of the combustion chamber. The fuel that touches the metal is “quenched” and doesn’t burn with the main charge. When the exhaust valve opens and the cylinder pressure drops, this fuel evaporates, making the blue smoke that you see in the exhaust.

By adding a cetane improver, you make the fuel ignite at the proper time and all types of emissions are reduced. You engine will have more power, be more efficient, and have fewer operational problems.

Fuel Filters

Here are some examples of fuel filter elements in different stages of life. We recommend that fuel filters be changed at least every year or 100hrs. If the filter, when you remove it, looks anything like the two lower photos, you should reduce the time between filter changes.

The elements below are just one type of fuel filter element, your vessel’s primary filter may look different, but it will perform the same functionRacorNew

Here is a fresh, new filter element for a popular primary fuel filter. It has nice, clean pleats on the filter paper. It only has to be immersed in fuel for a short time for it to discolor, but that doesn’t mean it’s in need of replacement.

Here’s a beauty! You can not make out the pleats for all the slime on it. Looking at this filter, we would recommend changing this filter a little more often.RacorClogged

Although this filter doesn’t have the external mess like the one above, it is waisted in the middle. This is caused by the vacuum generated by the lift pump on the engine. This filter clogged and the vacuum was generated as the fuel pump tried to suck fuel through it.RacorClogged2.

Heat Exchangers

Heat exchangers are the equivelant of the radiator in your car. The difference is the radiator transfers heat to the air and a heat exchanger transfers heat to sea water. Most heat exchangers are made of tube bundles where the sea water travels through the tubes and the engine coolant travels around the tubes. Exchangers can suffer all the problems that your car’s radiator does, plus some additional ones. The two most important items in the periodic maintenance list for heat exchangers is to keep the sacrificial zinc in good shape and to change the engine’s coolant regularly.

The zinc is provided to reduce corrosion in the heat exchanger. It functions by corroding away, “sacrificing” itself for the good of the copper in the exchanger. The zincs may need replacing every year or as often as every two months, depending on the environment and how the boat is used. It is better to replace the zinc before it needs it, rather on letting it dissolve away all together. If the zinc dissolves too far, you will not be able to remove the zinc portion from the threaded pipe plug. This isn’t a big deal, but it just adds a little cost. Also, if the zinc wears away unevenly, it can corrode at the base, letting the rest of the zinc fall into the heat exchanger. Not all exchangers have a sacrificial zinc as they are made of cupranickel alloy and don’t require the protection.

The coolant in your engine has a designed life expectancy. For “standard” ethylene glycol, it is two years and for “long life” propylene glycol antifreeze it’s five years. These are “projected” lifetimes and depending on the engine/service may too long between replacement. We use the term coolant because “antifreeze” is much more than it’s name. It has components that stop corrosion, lubricate pumps, and increase the boiling point of the coolant. Once the corrosion inhibitors get tired, then the coolant will begin to corrode parts of the cooling system, starting with the least noble metals, like aluminum. The seal in the water pump can fail if not lubricated properly. Coolant often contains “silicates” that can collect in the heat exchanger as it gets older, clogging it.

One of the most common problems is clogging of the sea water side of the exchanger due to foreign debris. The type of debris can vary from seaweed, to sand, to zebra mussels. Almost all heat exchangers have access plates that can be removed to clean out the debris. There are also calcium deposits that over time can block off the tubes or coat the tubes reducing the heat transfer. Acids can be used to remove the deposits, but it can eat through the tubes as well. Be sure to pressure test the exchanger after cleaning with acid. If you have replaced the sea water pump impeller and it had lost some of it’s blades, then most likely they have traveled through the hose to the heat exchanger. The pieces can lodge against the tubes and reduce the water flow.

Propellers versus Engines

When it comes to propellers there is quite a bit of mystery regarding which propeller is best for a particular engine and vessel. Although there are no sure fire answers, there are some guidelines. The proper propeller is instrumental in getting the maximum performance from your engine, regardless whether yours is gas or diesel, sail or power.

Each engine has a specific rpm where its maximum power is developed. The amount of power developed is a combination of rpm and torque. The faster the engine spins, the more power pulses are made and the more fuel is burned. Hence, the faster the engine turns the more power is developed. If the engine turns faster than it’s governor set for, then the governor will reduce the amount of fuel delivered and reduce the torque, reducing the fuel being burned . Inversely, if the propeller keeps the rpms below rated rpm, the lower rpm reduces the amount of fuel burned and therefore horsepower. A propeller that causes the engine to turn too fast or too slow will reduce the available power.

To determine what the proper rpm is for you particular engine, you need to consult your operator’s manual and look for it’s maximum rated power rpm. This is the rpm your engine should develop when underway in calm water. Some specifications provide “intermittent” power and “continuous” power. The intermittent rpm is the maximum power and is what the propeller should be sized for. Continuous power is the rating that you can cruise the engine at all day long. Take your boat out and get the engine warmed up. Open the throttle slowly until wide open throttle is achieved. With the boat operating at maximum speed, what is your maximum rpm? Is it less, or more, than the “intermittent” rpm in the manual?

Now comes the fun part. What to do with your prop? We’ll give you the simplified version by saying: Rpms are low, reduce pitch: Rpms are high, increase pitch. This is a huge simplification, but that is the basic idea. Most sail boats with a 2:1 transmission will respond by a change of approx. 300rpm for each inch of pitch change on the prop. Power boats can change more or less depending on type of boat, propeller, and gear.

Many owners are apprehensive about running their engines at wide open throttle as they don’t want to damage their engines. Running at rated rpm and throttle should be part of your diesel ( or gas) engines operating procedure. Not for extended periods of time, but just enough to make sure that your engine can still maintain full rpm. Conditions change, fuel load, people and gear load, fouling on the bottom and propellers, all contribute to slowing the boat (and engine) down. If your engine can only achieve 200 rpms less than it used to, then you need to reduce your cruising rpm as well. Otherwise, you will be operating the engine at a higher percentage output than you think.

So you have a new engine?

CONGRATULATIONS!! You have a brand new engine and it purrrrs like a kitten and it’s all shiny and bright. Here are a few pointers that come from frequently asked questions by new engine owners after we install it.

1. What is the break-in period and how do I run the engine? We normally consider 50 hrs. to be the “break-in period” on most engines. The engine really continues to “wear in” long after that, but as far as the owner/operator is concerned, 50 hrs. is it. During this time, we recommend that you avoid running the engine at high outputs for extended periods of time. If you want to give the engine a brief WOT (wide open throttle) for less than a minute, fine. It’s actually recommended to do that at least once each time the boat is used. This way you can make sure the engine will develop full speed and you can determine if anything has changed since the last time you used it. We like to have our customers “mix up” the rpms during the break-in period. This means don’t run the engine at one speed for the whole day. Every hour or so, change the engine speed, as much as practical. This changes the load on the engine and allows more complete break-in.

The first engine service, usually at 50hrs or so, is probably the most important service that your engine will have. This is where the oil and filters is changed which gets rid of all the particles of metal from the engine “wearing in”. In addition, you get remove any dirt or contaminants that might have been in the engine from the factory. Just like people under going an operation, engines get contaminated the worst from being taken apart and/or being put together.

At this point we also want to set the valve lash. Since the pushrods, rocker arms, and valves have all gotten to know each other better, they are not usually at the same setting as when they left the factory. Once we set the valves at 50 hrs., you can usually go for a couple of hundred hrs. before doing it again, but that will vary with each engine. If your 50 hr. check calls for re-torqueing the cylinder head bolts, then a valve adjustment is mandatory.

Engine alignment should also be checked at this point. The internal engine parts are not the only things that have gotten to know their neighbors better. The engine and the boat itself have figured out where they are going to be and that may not be the best thing for the propeller shaft. Engine mounts will tend to “settle” with vibration and pressure, finding where they want to be. They may allow the engine to fall lower in the boat, bringing the prop shaft out of alignment. As with the valve adjustment, once you align the engine now, you will not have to do it for several hundred hours.

Have you hugged your engine mounts today?

Most engine mounts are taken for granted and as long as the engine doesn’t fall off the beds, most people think everything is fine. Mounts and their systems are as important as anything else in the drive system. These devices have to hold the engine secure while isolating vibration from the boat. They have to allow the engine some amount of movement but still maintain the alignment to the prop shaft. Most mount systems have some type of “cushion” system, usually employing either rubber or springs of some kind. Springs can “work harden” over time and break, while the rubber (or “elastomer” can deteriorate through oxidation or chemical degradation. Fuel or lube oil leaking onto an engine mount will swell and soften the cushion material causing it to fail. The pictures below show just that type of failure. If the rubber looks “swollen”, it may have been exposed to petroleum products. Compare the mounts with each other. It is unlikely that all the mounts would have been contaminated equally. Be sure to find the cause of the contamination before you install new mounts.

Over time, the threads and nuts on an adjustable engine mount can corrode and become inoperative when it comes to adjusting the alignment. Most alignments don’t take that long, between 1-2 hours. If the engine is out of alignment, beyond what the mounts can compensate for, it may take much more time to get the alignment right as we may have to move the engine around quite a bit. Corroded adjustment nuts are the most likely cause of excessive alignment times, so every so often, apply some type of corrosion inhibitor to the nuts and threads of the mount. It will save you money in the long run.