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How Many Engine Hours Are Too Many?

fleming yacht sealogs

What to look for when buying a new boat

You've been saving every spare dollar and you're on the hunt for a new boat. You’ve already spent hours scrolling through online feeds: Facebook, Trademe Boats, and other Marine based sites, and you have narrowed down your search list to a defined ‘type’ of vessel. This 'type' of vessel quickly goes out the window though when you come across your dream boat... a 42ft, 2011 Fleming 78. A twin-screw boat with each engine having just over 4000 hours. The alternator and injectors were last serviced 2 years ago... or so you're told! 

Other than checking for the obvious things like leaks, it is difficult to ascertain how well this boat was 'looked after' or what the engine hours were if a rebuild did take place. Deciding if this is a good buy or not requires some thorough thinking and further investigation.


Here are a few tips to help you in your decision-making:


Cold Start the Engines

First, start engines individually and when they are cold. The engines should start within a couple of revolutions. If it takes more than 3seconds of cranking, there may be a compression issue - If the cylinders are not holding compression, the pressure is getting past the rings or the valves which then pressurises the crankcase.


Complete a thorough Visual Check

Next, do a visual check when you’re well secured alongside the wharf. In Neutral, bring up the RPMs to 1000 approx and remove the oil fill cap on top of the valve cover. If there is a lot of air escaping (enough to float a tissue or paper towel - especially if it's laced with oil) indicates there may be a compression issue.
So what to do, *seek expert advice* unless you're a keen learner or have the relevant experience in which case you could conduct a compression check yourself which is a good indicator of the wear of piston rings and/or valves. Wear accelerates when there isn't enough oil or the valves are allowed to get out of adjustment. Unfortunately, checking compression on a diesel engine is much more difficult than a petrol engine because you have to remove each individual injector, which is likely to require adapter tools, and these vary by injector - so make sure you check these adapters fit first.


Check the vessels Exhaust

Next check the exhaust. There may be some oil in the exhaust with a minor slick. A small amount of blue/grey smoke is not uncommon but should disappear within a few minutes. Once warmed up, the engine should idle smoothly without 'loping' (RPMs varying up/down). Sustained or excessive smoking, oil slick or uneven running may be a sign of worn injectors or injector pump. Steam is normal depending on the ambient air temperature.


Have Some Fun - Go for a Blast!

Make sure you take the boat out for a sea trial. The engines should be capable of running with a wide-open throttle for 10-mins without blowing too much black smoke or overheating. It's important to monitor the gauges during this time especially the oil pressure and water temperatures. Our advice would be to let the owner drive, just in case it overheats.


Send away an Oil sample for a detailed analysis

Another option is to take an oil sample and send it away for analysis. This may seem over the top, but it will generate a report on the internal state of the engines and at a bare minimum, the results will tell you if there is sodium (salt water) in the engine. You never know if an owner has recently changed the oil and completed a service to hide a known defect, so it’s good to pay attention. Likewise, check for a date written on the oil filter as this is common practice.


Look down!

Finally check the bilge. This should be dry. If there is a leak or a weep, this should be fixed as soon as possible as there is no such thing on a boat as an acceptable leak... unless it’s being cooked for lunch!


Engines and mechanical parts do have a recommended ‘design life’ and often the 5,000-8,000hr figure is used. I’ve heard of fishing vessels that have main and auxiliary engines exceeding 20,000 hours without major maintenance issues. I have also heard of a John Deere engine that was regularly serviced that had over 30,000 hrs on the clock and I’m certain there will be more examples of engines lasting longer.


Overloading or having poor maintenance practises will radically reduce an engine's service life, and as you can see, there is no simple rule when buying a boat. You need to carefully consider all the aspects mentioned in this article, trust your gut feeling about the owner's honesty, and look after your engines - they, in turn, will look after you.


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Create a detailed maintenance trial and stay on top of your Engine and parts servicing with SeaLogs.
SeaLogs provides a simple to use Inventory and Tasks add-on. Record Inventory items, Tasks and more all from leveraging the foundation of your logbook! 
For more information sail to SeaLogs - we'll sea you there! 




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