• If this is your first visit to the iboats.com Boating Forums, be sure to check out the FAQ. To post a question or comment, begin by signing up. To start viewing messages, select the forum that you want to visit from the selection below.

Announcement

Collapse

Help Tip: If you have a question that has not been answered to your satisfaction in the archives, it is always best to start a new thread of your own. By starting your own thread, you will receive the maximum number of views by forum members.

Below are some additional forum policies in hopes of all iboats members will follow, Thank you.

1. Please do not reply to old topics or hijack existing topics. Old topics of a technical nature are like a library book, Please do not write in them.

2. Old topics should be considered archives and used for reference only. Please do not reply to them.

3. Do not take over someone elseís topic (aka hijack) with your own question, even if it is similar. If you have a question that has not been covered to your satisfaction in the archives, it is always best to start a new topic of your own.

4. If you have a question for the original poster (OP) and the topic is over 30 days old, send the OP a PM, he may not even visit the forums any longer, or may not notice your question in the old topic.

5. By starting your own topic, you will receive the maximum number of views by forum helpers that may not even notice your question when itís posted at the end of someone elseís topic. And those answers will be specific to your particular issue.

6. Please do not post to topics that have been inactive for more than 3 months unless you are the original poster. We have very active forums and any topic that remains inactive for that long should be considered "dead". It is especially confusing when there is an entirely new question posted to an old topic.

7. Posting at the end of any topic is considered to be hijacking the original posters topic which in turn subjects the topic to be closed if it continues to happen thus not making it fair to the original poster in the future had for some reason he/she needed to return for additional information or provide an update of the problem solved which is always welcomed within a reasonable amount of time frame.

8. Please note that you should see a red banner pop up near the bottom of each inactive topic asking you not to reply to old topics. The Red banner will read: Please note this topic has been inactive for 90 days. For the best results, please start a new topic.

Thank you all in advance for doing your part in helping iboats run a smooth ship.

Additional forum rules linked below.
http://forums.iboats.com/forum-rules-guidelines-405/
See more
See less

Repower - 357 Mercruiser 4V OR 350 MAG MPI

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts


  • Repower - 357 Mercruiser 4V OR 350 MAG MPI

    Boat is a Sea Ray Sundancer 240 and my old 5.0 EFI (Throttle Body Inj) is shot. Looking to repower with a complete engine package from Mercury. Down to two options:

    1. Reman 357 Bravo 4V carbed, 325 HP (at crank) and 3 year warranty from Mercury

    2. CPO 350 MAG MPI, 300 HP (at prop) - same warranty as above I think.

    I am concerned about the added fuel consumption of the carb motor. I had TBI on my old motor and it still sucked gas. Maybe a tired motor on a heavy boat? Will the carb motor really drink much more gas vs the MPI?? Also, will the driveability / startups be that much better with the MPI?? I have never had carb before on a boat. I only use my boat for about 50 hours a year....Cost difference between the two motors is apprx $1600. Any thoughts appreciated.

    Ed
    "Fender Bender"
    2002 Sea Ray Sundancer 240
    357 MAG 4V 325HP, Bravo III


  • #2
    Re: Repower - 357 Mercruiser 4V OR 350 MAG MPI

    Well, the starting will likely be much quicker with an MPI over the carb, but you won't notice much of a difference other than that. They both have similar HP and fuel efficiency on a properly tuned carb, is similar to that of fuel injection, they just go about it different ways. You'd have to install a high pressure fuel pump with the MPI versus the mechanical version used on the carbs. It's really just a matter of whether the extra $1,600 is worth it for better cold starts (hot starts on both are the same).
    1976 Mark Twain 200VBR w/Mercruiser 233 (Ford 351w) "Heart & Soul"

    Comment



    • #3
      Re: Repower - 357 Mercruiser 4V OR 350 MAG MPI

      Originally posted by haulnazz15 View Post
      Well, the starting will likely be much quicker with an MPI over the carb, but you won't notice much of a difference other than that. They both have similar HP and fuel efficiency on a properly tuned carb, is similar to that of fuel injection, they just go about it different ways. You'd have to install a high pressure fuel pump with the MPI versus the mechanical version used on the carbs. It's really just a matter of whether the extra $1,600 is worth it for better cold starts (hot starts on both are the same).
      Thanks - another consideration I had was the cost of potential future repairs on the MPI engine (fuel pumps, ECU, sensors, etc).
      "Fender Bender"
      2002 Sea Ray Sundancer 240
      357 MAG 4V 325HP, Bravo III

      Comment



      • #4
        Re: Repower - 357 Mercruiser 4V OR 350 MAG MPI

        Originally posted by edsmax View Post
        Thanks - another consideration I had was the cost of potential future repairs on the MPI engine (fuel pumps, ECU, sensors, etc).
        The sensors don't fail often enough to worry about that cost. For the same amount in sensor/pump repairs, you would have to assume the same with mechanical fuel pump and carb rebuild/maintenance. 6 of one/half dozen of another.
        1976 Mark Twain 200VBR w/Mercruiser 233 (Ford 351w) "Heart & Soul"

        Comment



        • #5
          Sign up today
          Re: Repower - 357 Mercruiser 4V OR 350 MAG MPI

          Conversion is done - went with the 357 MAG 4V. So far very happy and a clean install. Totally different boat with this engine vs the old 5.0.
          "Fender Bender"
          2002 Sea Ray Sundancer 240
          357 MAG 4V 325HP, Bravo III

          Comment


          Working...
          X