Logo
Click for Volvo Penta parts and manuals!
Results 1 to 4 of 4
  1. #1

    Default 5.0 to 5.7 with RPM issues after change over

    I recently had my busted 5.0 block on my 1999 FourWinns 238 Vista switched to a new 5.7 replacement block. All other systems on the boat were kept from the original. ECM was sent off to be reflashed and now that the boat is back together I cannot get the boat to run past 2500 RPMs. Boat will run fine at 2400 and below but as soon as you go past 2500 the RPMs will bottom out and bounce back and forth between 2500 and below 1000. First was told that the timing was not set properly on new block so had a local marine tech come out, who used program on his PC to properly set timing. Just went down last night to test out after work was done about 10 days ago and had the same issue, other than now it bounces down so low it almost stalls out. I have seen post talking about blocked exhaust, fuel vapor lock, ECM locked in slow mode, fuel pressure, fuel water separator issues, fuel cooler (not sure I have one). I did not put new block in myself had friend of a friend do this and motor came from well-known boat motor replacement company. They are ones that suggested that timing was off and that is why it would not run. They were also the ones that sent my ECM off to be reflashed. I need help almost $5500 in the hole now without a running boat. Thanks in advance to help, Niner

  2. #2
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    9,191

    Default Re: 5.0 to 5.7 with RPM issues after change over

    You (or the mechanic) will do best if you used the tried and proven P of E! (Process of Elimination)
    Check/replace one item and one item ONLY at a time before moving to another suspect area!

    The P of E will not let you down when used systematically and methodically!
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

    Please... no PMs! Post your questions on the forum.

  3. #3
    Join Date
    Dec 2006
    Location
    Chaumont Bay, N.y., USA
    Posts
    5,218

    Default Re: 5.0 to 5.7 with RPM issues after change over

    I recently had my busted 5.0 block
    Ayuh,.... What killed the old motor,..??

    That in itself may be a clue to what's goin' on now,...
    Any Grease is Better,... Than No grease at All....

  4. #4
    Join Date
    Dec 2016
    Location
    Cave Creek, AZ
    Posts
    34

    Default Re: 5.0 to 5.7 with RPM issues after change over

    Having owned a 238 vista, I want to point out that your rpm issue sounds -exactly- like what mine did right before the fuel pump failed.

    mine was a 96, but the fuel pump did slowly fail. And when it did, the boat wouldn’t start. I replaced it (super easy) and never had the problem you described ever again.

    I know you are looking at apples and I just threw an orange. But check your fuel pressure before you start messing with anything else.

Similar Threads

  1. High Idle, Cannot retard /change timing to change RPM
    By Canufixit in forum Mercury Mariner Outboard Forum
    Replies: 1
    Last Post: 08-09-2017, 10:36 AM
  2. High Idle, Cannot retard /change timing to change RPM
    By Canufixit in forum Mercury Mariner Outboard Forum
    Replies: 1
    Last Post: 08-09-2017, 10:36 AM
  3. 1974 Mercury 1150 I6 Impellor Change, Stator Test, Spark Plug change
    By bassboy416 in forum Mercury Mariner Outboard Forum
    Replies: 0
    Last Post: 04-28-2014, 10:42 AM
  4. Replies: 5
    Last Post: 01-16-2011, 12:42 PM
  5. Change muffler on 471dd marine any issues
    By gerry_fowler in forum Detroit Diesel
    Replies: 6
    Last Post: 07-27-2008, 01:02 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •