Help with 5.0 efi

Discussion in 'Gas Engines/Drives/Transmissions/Props' started by Jeff Delbuono, Jun 13, 2018.

  1. Jeff Delbuono

    Jeff Delbuono Member

    101
    Jun 11, 2018
    Edison new jersey
    1998 sea ray 290 sundancer
    5.0 efi
    I just got a 1998 sea ray 290 sundancer with twin 5.0 efi on alpha 1 gen 2 drives. Sat for 7 years on blocks. Both motors run awesome at idle but a little rich. When i take it out on water WOT neither will go past 3200 rpm( right 3200 rpm , left 2800 rpm) already changed fuel injectors, cap rotor, plugs fuel filters, knock sensors, coils, ignition moduels, fuel pumps, pick ups, vent lines. Ran on seperate fuel tank and same to both. Any clue where to go next. Driving me crazy
     
  2. CliffA

    CliffA Well-Known Member GOLD Sponsor

    Dec 29, 2009
    Lake Norman, NC
    2001 Sea Ray 340DA
    Name: 'Happy Place'
    4.5kW West. Generator
    Purchased Nov. 2014
    Fresh Water Use
    Twin Merc. 6.2L (MPI)
    Raw Water Cooled
    V-Drive Transmissions
    might be a prop pitch problem....someone may have put on a couple props with too high pitch to try and get a little more top speed.....but that can result in 'lugging' the engines and not allowing them to reach the WOT rpm range.....a dirty hull bottom can also significantly produce drag on the boat which will cause the engine rpm's to not reach the WOT range....if water was allowed to sit at a high level in the engine room while it was not active all those years it could be the stringers and maybe transom are full of water causing a lot of extra weight and drag.....

    good luck....
    cliff
     
  3. Little Ducky

    Little Ducky Well-Known Member

    Jun 5, 2017
    Chattanooga TN/Dickson TN
    1998 SeaRay 290 Sundancer
    Twin EFI 5.0L w/Alpha 1 drives
    Sounds like a great boat. ;)
     
  4. Strecker25

    Strecker25 Well-Known Member

    Nov 20, 2014
    Rochester, NY
    1998 290 Sundancer
    Twin 5.7EFI/Alphas, Kohler 4kw
    You’ve changed a lot already so it might be something abstract. Did you pull the drives? Since it say so long maybe the rubber exhaust flappers dried out and flew down the Y pipe. They get stuck at the transom and add a bunch of back pressure reducing RPm and power.

    What temps do the motors run at, and what speed are you doing when you’re at that 2800/3200?
     
  5. Jeff Delbuono

    Jeff Delbuono Member

    101
    Jun 11, 2018
    Edison new jersey
    1998 sea ray 290 sundancer
    5.0 efi
    Drives were taken off and sent out for service. New water pumps and impellas and presure tested. Put back on with props that came with it and owner said he never had a problem with them befors. Engine room is dry and solid. Spend 7 weeks cleaning it and has new bottom paint so no drag. Temps on both are 170
     
  6. CliffA

    CliffA Well-Known Member GOLD Sponsor

    Dec 29, 2009
    Lake Norman, NC
    2001 Sea Ray 340DA
    Name: 'Happy Place'
    4.5kW West. Generator
    Purchased Nov. 2014
    Fresh Water Use
    Twin Merc. 6.2L (MPI)
    Raw Water Cooled
    V-Drive Transmissions
    it sounds like you are doing the right things and have a good knowledge of what you are doing and why....I have heard of someone accidentally installing a 6 cylinder rotor button in the distributor of an 8 cylinder engine and having all kinds of issues....I believe the rotors for both the 6 cylinder and 8 cylinder engines look identical....the only difference being the number of teeth of the rotor to produce the correct 'hall effect' through the ignition sensors inside the distributor cap.....when you said you changed the 'ignition sensors' are these the ones inside the distributor cap?.....

    have you checked the ignition timing?....

    are both starting batteries in good condition?.....EFI engines like to have a strong and consistent voltage in the ignition system.....

    cliff
     
    Last edited: Jun 13, 2018
  7. JimG

    JimG Well-Known Member SILVER Sponsor

    Nov 4, 2008
    Southern WV
    2007 310 DA
    Kohler 5ECD
    Twin 350 Mags
    Raw Water Cooled
    V-Drives
    As Ryan asked, how fast are you going at 3200 RPM? Maybe a tach problem?
     
  8. Jeff Delbuono

    Jeff Delbuono Member

    101
    Jun 11, 2018
    Edison new jersey
    1998 sea ray 290 sundancer
    5.0 efi
    The one that attatches to dist. At 3200 im doing approx 12-15 mph. Boat just stands up. Bow will not drop
     
  9. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    Original engines could be tired after 20 years. Engines don't like to sit for 7 years either.
    Compression test might not be a bad idea.
     
  10. CliffA

    CliffA Well-Known Member GOLD Sponsor

    Dec 29, 2009
    Lake Norman, NC
    2001 Sea Ray 340DA
    Name: 'Happy Place'
    4.5kW West. Generator
    Purchased Nov. 2014
    Fresh Water Use
    Twin Merc. 6.2L (MPI)
    Raw Water Cooled
    V-Drive Transmissions
    just for 'peace of mind' I would verify the size and pitch of the props are correct for that boat and drive system....just because the owner said he 'never had any problems' doesn't mean maybe a previous owner before him had changed the props.....the size and pitch of the props should be engraved on the props....

    it sounds like you did not have a survey done or this performance issue would have been discovered prior to purchase....

    cliff
     
  11. Jeff Delbuono

    Jeff Delbuono Member

    101
    Jun 11, 2018
    Edison new jersey
    1998 sea ray 290 sundancer
    5.0 efi
    No survey. Will def check on prop size and pitch. Motors have under 400 hours on both. Compression test was done and is fine. Gonna try the timing. Thinking one motor lagging ot out of timing and dragging other down
     
  12. CliffA

    CliffA Well-Known Member GOLD Sponsor

    Dec 29, 2009
    Lake Norman, NC
    2001 Sea Ray 340DA
    Name: 'Happy Place'
    4.5kW West. Generator
    Purchased Nov. 2014
    Fresh Water Use
    Twin Merc. 6.2L (MPI)
    Raw Water Cooled
    V-Drive Transmissions
    those engines probably have the Mercruiser 'Thunderbolt V' ignition system...you may already know this but you have to put the system into 'base timing mode' before you check the timing....

    I had a lot of problems in a previous boat with the TBV ignition system...I eventually just replaced the whole system with a Delco marine ignition system that worked perfectly....

    cliff
     
  13. Jeff Delbuono

    Jeff Delbuono Member

    101
    Jun 11, 2018
    Edison new jersey
    1998 sea ray 290 sundancer
    5.0 efi
    They do not have the thunderbolt. Gonna see tonight with timming.
     
  14. CliffA

    CliffA Well-Known Member GOLD Sponsor

    Dec 29, 2009
    Lake Norman, NC
    2001 Sea Ray 340DA
    Name: 'Happy Place'
    4.5kW West. Generator
    Purchased Nov. 2014
    Fresh Water Use
    Twin Merc. 6.2L (MPI)
    Raw Water Cooled
    V-Drive Transmissions
    good luck....keep us informed on your progress....there is a vast amount of knowledge on this forum...I'm sure eventually we collectively can figure out what is going on.....

    how old are the starting batteries?...

    cliff
     
  15. GoFastr

    GoFastr Cool Runnings GOLD Sponsor

    148
    Jan 20, 2016
    Cayman Islands
    2003 Sea Ray 270 SunDeck MX 6.2L MPI w/Bravo III
    Tow: 2012 Ford F150 Raptor SVT
    Mercruiser MX 6.2L MPI w/Bravo III
    I had a very similar problem with my 210 SD with a single 5.0L EFI. I changed all the same things you did and it would rev out to 4500 rpm on muffs but couldn't get up on plane in the water. I finally took it in to a marina to have them look over it and they called me in the afternoon and said come and get it. I thought maybe they did something with the timing not advancing and asked what all they did to it, but he just smiled and said that was their secret but it is fixed now. All they would tell me was that they put a new Turning Point prop and hub on it and it runs fine now. The OEM prop was a 14x19 and the TP prop is a 14.25x17.
     
  16. Jeff Delbuono

    Jeff Delbuono Member

    101
    Jun 11, 2018
    Edison new jersey
    1998 sea ray 290 sundancer
    5.0 efi
    Thanks. Props are fine and in good shape. Gona put a fuel pressure guage and vacume guage on it under a load and see. Then Gonna put a timming light on it and see if it is the timing not advancing. Boat is new to me so when i got it anything that was old was tossed and new was installed. Batteries are about 3 weeks old
     
  17. KevinC

    KevinC Well-Known Member

    Feb 25, 2011
    Long Island, NY
    2004 340 Sundancer
    1988 Proline Center Console - 90hp Mariner/Mercury
    1969 Boston Whaler
    Twin 8.1 V-drives
    Jeff, do not discount the props. Even perfect props that are the wrong size, pitch or cup could be part of the problem.

    You also mentioned doing cap and plugs etc. Go back to some basics and also verify the wires are running from the distributor to the proper plugs - Its a simple check and can cause similar problems too.

    -Kevin
     
    GoFastr likes this.
  18. Jeff Delbuono

    Jeff Delbuono Member

    101
    Jun 11, 2018
    Edison new jersey
    1998 sea ray 290 sundancer
    5.0 efi
    Kevin. Thanks. That is def on the list tomorrow to check. This site is very good with kmowing their stuff. Everything discussed is a possible gremlin
     
  19. CliffA

    CliffA Well-Known Member GOLD Sponsor

    Dec 29, 2009
    Lake Norman, NC
    2001 Sea Ray 340DA
    Name: 'Happy Place'
    4.5kW West. Generator
    Purchased Nov. 2014
    Fresh Water Use
    Twin Merc. 6.2L (MPI)
    Raw Water Cooled
    V-Drive Transmissions
    I would also verify that when the #1 piston is at TDC the rotor button is pointing to the #1 spark plug position on the distributor cap.....

    and agree with Kevin to double check you have not accidentally mis-routed the plug wires.....

    cliff
     
  20. cfd95

    cfd95 Member

    288
    Nov 5, 2013
    Northport Long Island
    2002 310 Sundancer
    350 Horizons
    V Drives
    You said the motors are running rich at an idle.
    Something is telling the ECM to richen the fuel mixture IE-Map Sensor/Engine coolant sensor/dead cylinder causing low vacum or a vacuum leak.
    Have you checked the fuel pressure throughout the RPM range when under load .
    Did you replace the fuel pressure regulators and fuel coolers when you did the fuel pumps.
    I would get a scan tool on the engines and read the parameters of the sensors. And check for codes.
    Google the repair manual theres plenty of sites that have them in PDF for free.
    The specs for the sensors and fuel pressure are in the manual as well as trouble shooting trees.
     

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