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  1. #1
    Join Date
    Aug 2006
    seattle, wa, usa

    Default Gray Marine 6-71 serial number

    Doing searches here and internet in general, and in the service manual, I cannot make sense of this serial number. The boat is a 1964, and I believe this engine is original. Looking at the front starboard side of the engine, there is only one number stamped into it- not two (serial and model) as everyone including the service manual says there will be.

    It starts with a small five point star, and then reads : 671134057

    On the valve cover is a plate that just says ; Gray Marine Diesel.

    Any information on what year and model number this is are appreciated! (or ideas on how to find out)

    Thanks in advance.

  2. #2
    Join Date
    Nov 2009
    temecula, ca., usa

    Default Re: Gray Marine 6-71 serial number


    Well, I highly doubt that the 671 at the lead of that sequence is a numerical coincidence but I really don't know.

    The link below is from a Gray Marine dealer but I see no reference to anything that looks like a diesel engine. I offer it to you just "because".

    I read that Gray Marine was supposedly sold to CONTINENTAL ENGINES back in 1947 and they shut down the brand in the mid 60's. If that is true, it may be a lead for you to follow up with Continental.

    It's a daunting task to track down info on this stuff because of all the "swapping" that was done in the boat business. The engines are so robust, they would last for many years and, sometimes, would go from hull to hull to hull in boat "resurrection" projects. Even to the point of coming out of a used boat to power up a new model!

    If you really think that engine is original to THAT vessel, then I would be trying to find anyone left around that may have some knowledge of where the keel was laid and by whom. If you could find "those guys", they might be a treasure trove of knowledge.


    Good luck.

  3. #3

    Default Re: Gray Marine 6-71 serial number

    2 -1/2 months late and not sure if it helps but there is another 6-71 on the internet and they say serial number :671139206
    Model number : 671LA3?M

  4. #4
    Join Date
    May 2015

    Default Re: Gray Marine 6-71 serial number

    Gray Marine used 671 as at the start of the serial # until serial numbering system changed sometime in the mid to late 1960s. Then 6A was the 671 prefix. I've never seen a serial number list for older 671s, but have 2: 67124072 & 67174300 and was told they are 1947 & 1948. I would guess yours is about 1950. Most manuals from WWII to early 1960s should have good info. Find a parts book. Detroit Diesel can convert the numbers to current. I would love to have that cross reference.

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