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How to pre-check an engine for delivery or purchase DIY

Discussion in 'Engines' started by yachtwork, Jan 1, 2010.

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  1. yachtwork

    yachtwork New Member

    Joined:
    Jun 25, 2007
    Messages:
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    Location:
    New Zealand
    Here is an article that shows a system we use when picking up a boat for delivery or when considering purchase. It's non invasive and can be completed by most DIY techs.

    Technician Engine Analysis Checklist

    By: Scott Fratcher - Marine Engineer/Captain

    An engine analysis is an advanced system of inspecting our boats drive train. We perform these tests to help catch pending mechanical issues before we leave the dock. An analysis is much more comprehensive than a typical “pre-departure peak” at the engine. We are going to not only visually inspect our engine, but also take a series of measurements that become our baseline for future tests. Our goal is use this engine analysis as a system to help make easy informed decisions about our boats drive system.

    To begin you should have on-hand as much of the following as possible:

    * · Camera
    * · Notepad
    * · Your collection of electrical meters
    * · A 0-3 bar pressure gauge (if your engine has a turbo)
    * · An infer red temperature gauge
    * · Any other special tools you might have
    * · A few rags, and spray cleaner


    The steps to performing an engine analysis:

    1. Visual inspection

    2. Pre inspection

    3. Bollard pull

    4. Analyzing the numbers


    Visual inspection

    This is a general once over of the engine looking for blatant flaws.

    Open the engine room door, look, feel and smell

    Look for oil drips or other fluid under the engine. Inspect for obvious cracked hoses. Give a gentle bend where a hose attaches to the engine and look for cracks in the rubber cover. Check the fan belts for cracks and loose hose clamps. Grab the alternator pulley and see if it will spin free on the belt. If it does then the belt is worn or loose.

    Feel the inside of the engine room for oil film. Touch the areas of the engine you can’t see feeling for rust or salt trails.

    Smell for any burned chemical type odor. Smells can be difficult to locate, but in general any burnt, oily, or diesel smells should be searched out. A good nose can tell the difference between a hot belt and a hot wire.

    Look over the complete engine for oil leaks. Pay particular attention to the front seal, and the area between the gearbox and engine. Leaks in the front or rear seal can mean a coming engine rebuild. Inspect the head to block connection looking for oil or water trails.

    Take photos from all angles as a base line for later use.

    This is the point where many an engine inspection ends, but in an analysis we want better scrutiny to help build confidence in our propulsion system.

    Our next series of checks focus on fluid inspections


    Oil

    Oil is the lifeblood of our engine. It lubricants, cools and quiets our engine. But how do we know if the oil is doing its job?

    Begin by pulling the dipstick. Smell for signs of diesel odor. Pinch a small dab of oil between your index finger and thumb and expand slowly to see how far you can spread the oil before the gap opens. Compare this gap to new oil and take down the difference for your notes. This is a crude method of checking viscosity and diesel intrusion.

    Open the oil fill and look inside the cap for water droplets, condensation or worse, a gray gooey substance indicating water penetr ...

    Scott
  2. dennismc

    dennismc Senior Member

    Joined:
    Jan 29, 2009
    Messages:
    1,175
    Location:
    Vancouver BC
    Anyone who really carries out the "bollard" strain test as noted here should be fired, imagine, 2000 HP at full rpm with the boat at anchor in reverse, or even tied to the dock....
  3. yachtwork

    yachtwork New Member

    Joined:
    Jun 25, 2007
    Messages:
    4
    Location:
    New Zealand
    Bollard pull test

    Dennis- Thank you for your thoughts. I have this in the article-

    ... or higher horsepower yacht consider getting underway for this test ...

    Your not the first to mention this so I think I should make it more clear. Thanks for pointing it out.

    Scott
  4. Bamboo

    Bamboo Senior Member

    Joined:
    Dec 19, 2008
    Messages:
    934
    Location:
    Palm Beach, FL
    Look for oil drips under the engine? Feel the engine room for oil film? You obviously have never had a DD 53/71 or 92 series. If it does not leak then it has no oil, and if it has oil and you don't see the leak then the last guy cleaned it and he is hiding something.
  5. Henning

    Henning Senior Member

    Joined:
    Sep 22, 2009
    Messages:
    940
    Location:
    Ft Lauderdale FL
    If you put a good air/oil separator into the breather line, you should be able to keep even the old Jimmies clean and dry, and just because someone wipes up after an engine doesn't mean he's hiding anything, just controlling a mess.
  6. K1W1

    K1W1 Senior Member

    Joined:
    Sep 30, 2005
    Messages:
    7,388
    Location:
    My Office
    Hi,

    Did I mis something here?

    I don't see anything in the first post past giving the Lube Oil the finger.
  7. geriksen

    geriksen Senior Member

    Joined:
    Jul 24, 2007
    Messages:
    175
    Location:
    San Juan Puerto Rico
    I keep hearing how Detroits spew oil everywhere. That has not been my experience. I have owned three boats with Detroits, J+T 671's, 6V92 DDEC's and 8V92's. All have stayed super clean with no leaks or "oil fogging" in the bilge. And two of them did not even have Airseps...
    But, I also take care of them and don't run the crap out of them all the time.
    Personally, I love the 2-cycle Detroits.