Replacement engine for 2001 Captiva 272 with 454 Mercury engine

madst3215madst3215 Member Posts: 9
My engine lost pressure in one of the cylinders so I have a decision to make, repair this OEM engine or replace it.  What is the largest HP engine that can fit inside the engine compartment or the best economic one that is lighter but around 300_350 HP?  I don't know how to size one or where to begin looking for an engine replacement. Any advice?

Best Answers


  • WillhoundWillhound Lake Simcoe, Ontario, CanadaMember Posts: 3,345 ✭✭✭✭✭
    edited February 2019
    A suggestion on repair or replace is tough without knowing other details like total hours, any other issues, have you been satisfied with the performance of the original block? Any other work that needs to be done?
    Edit: Oh, and welcome to the forum, just noticed it was your first post!
    "Knot Quite Shore" - 2000 FV270
  • reneechris14reneechris14 Pawcatuck river CTMember Posts: 2,975 ✭✭✭✭
    Welcome to the RBOC forum I think a rebuild would be your best option. A 454 block is usually a strong platform. 
    2005 Rinker FV342  Pawcatuck river,Ct
  • madst3215madst3215 Member Posts: 9
    Thanks for the inputs.  Some more info: it has about 300 hours and I have been very happy with motor but I didn't winterize it while I was out of town and the freeze plugs popped a couple times in the last few years.  We were starting initial assessment when the bolt were so rusted we couldn't remove them without several hours of work. Now i are quoted at a couple grand to just get the engine open to determine the problem.  So I have been wondering if the initial few grand would be better spent on a new engine or suck it up and pull the original and take a chance.
  • skennellyskennelly ChicagoMember Posts: 1,708 ✭✭✭✭
    Not winterized?  Maybe the block is cracked
    2002 - 270FV Mag 350 B3
  • randy56randy56 Newburgh INMember Posts: 3,148 ✭✭✭✭✭
    Click here for more information about ATK Marine Engine DM25 - ATK Marine Rebuilt Long Block Engines
    This about $3050, without shipping. if you can pull the other one out and bolt on your parts, then reinstall. If you have the ability or tools to do it your self. 

    Crate Engine, Marine, Long Block, Assembled, External Balance, Cast Iron Heads, Chevy, 454, Each


    Part Number: HME-DM25 More Detail...

    Boat Name : 

  • AlswaggAlswagg Member Posts: 2,821 ✭✭✭✭✭
    If you do replace, make sure you buy the correct version.  Mark VI    If you want to upgrade, now is the time.  496  base is  direct swap.  Must buy complete Mercruiser package.  
  • madst3215madst3215 Member Posts: 9
    Thank you for your advice.  I don't believe the block is cracked but there is a slim chance.  I had it winterize this last year when I used it so I think the low pressure in the cylinder is the problem.  I will look into the two engines mentioned.  Those are much cheaper than the new ones I have seen online or my mechanic quoted me.  They are says 12k plus labor. They would give me $600 for the old engine but that seems low too. How do I determine what engine can fit in the current space?  ALSWAGG you said ensure its a Mark VI, where do I go to look at engines that fit and determine what is the max HP I can install? Do I call rinker or do crate engine companies have dealers that can quote me the information?
  • AlswaggAlswagg Member Posts: 2,821 ✭✭✭✭✭
    Call Eagle engines.  Or Michigan Motorz.  Both are quality suppliers.   You currently have a 454 Vortec Mark VI    A mark Iv will not work in your application. A Mark V will.  These are GM designations.   
  • madst3215madst3215 Member Posts: 9
    Thanks for the comments. I will look to rebuild this engine and get more time out of it. This is a great forum to get knowledgeable about my boat. Thanks everyone. If anyone has more advice please let me know.
  • pistolepistole Member Posts: 158 ✭✭
    Al is always helpful
  • Dream_InnDream_Inn Annapolis, MDMember, Moderator Posts: 6,254 mod
    @madst3215 Please keep us updated on what you do and post some pictures.  You can definitely learn a lot from the people here, but we can learn from you.  Pictures from your rebuild, or whatever you decide, can help the next person making the same decision.  Good luck!

    Dream 'Inn III -- 2008 400 Express

  • AlswaggAlswagg Member Posts: 2,821 ✭✭✭✭✭
    I suspect you have a bad valve.  
  • JoeStangJoeStang Metro DetroitMember Posts: 1,064 ✭✭✭✭
    300 hours is very low hours for a big block, unless it wasnt maintained properly. I'd get a second quote on diagnosing the problem first, before pulling it out.
    2013 276 Cuddy ~ 350 MAG / B3
  • madst3215madst3215 Member Posts: 9
    I haven't made a decision yet. The last boat repair shop couldn't get the engine open due to rusted bolts. Now I have to find someone who can torch off the broken bolts to see what is wrong inside. More money it seems to me.  I am looking at a rebuild due to costs. 
  • madst3215madst3215 Member Posts: 9
    Thanks for your input.  I have been talking to other boat shops and some won't touch in season due to age. Others will do a rebuild but they say due to age and running in salt water for over 15 years they say total rebuild may be right move. I flushed and sprayed it religiously but know it's old and I want piece of mind. One marina quoted $11,700 383 for mag bravo and $2500 in labor. This is new engine with all new parts attached. Is that a good deal? Sounds high to me and past performance has been mediocre.
  • madst3215madst3215 Member Posts: 9
    The manifold bolts are rusted with a couple broken off. That stopped the last marina from making a full diagnosis.
  • madst3215madst3215 Member Posts: 9
    Update. I have some money coming in and am looking at getting a new engine. More I read about a 19 year old engine run in salt water the more they say replace the whole thing. I have a local boat mechanic looking for a good replacement for my 454 Mercury and am trying to find the best complete engine for the most horse power around 12-14k. Looking for advice or recommendations for pricing and getting most power from it.
  • madst3215madst3215 Member Posts: 9
    Update: I finally have scrapped money and time together and will get the boat fixed. I have decided to get a rebuilt engine to give me piece of mind. I am looking at a 454 mpi replacemnt with 325-350hp for $6500 and a 8.1 425hp rebuild waiting on pricing. Anyone have an opinion on power versus torque to be worth the extra money? I am going to make this boat as new as possible. Change all fluids, new gauges full detailing with new stickers and carpeting. I will get some before and after pics soon. I am getting a quote on each engine and will post that for advice. I want to put a new refrigerator in but not many comments on the value of doing it. Is it a DIY or just let mechanic do it? Thanks.
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