Power loss under load

Discussion in 'Gas Engines/Drives/Transmissions/Props' started by Zim, Aug 13, 2019.

  1. Zim

    Zim Active Member

    162
    Jan 16, 2018
    2012 Sea ray sundancer 310
    Twin merc
    Hi all,
    Wondering if anyone can provide some direction.
    2012 searay with 5.0 bravo 3s. Engine id 1A653471. Port engine won't rev past 2k rpm under load. Starts fine, idles fine, all is well, but under load, max rpm is 2k and alarm sounds, stating power loss. Once i shift into neutral alarm goes away with no codes. Doesn't stall or back fire. No ticking or knocking, oil is clean, engine temp is normal as well as oil pressure. In neutral, throttle only, no issues in hitting rev limiter. I checked the obvious, fuel pressure, approx 38-39 psi, filter is clean, no contamination to include the mesh filter on bottom of filter housing...cool fuel module was recently replaced. I don't believe it's a fuel issue, maybe a sensor, injectors? Thought not positive on fuel issue...maybe blocked line? I keep second guessing myself. Problem just started after replacing the cool fuel module, ran fine for a long cruise approx 2 hrs at wot and boom, no power. Oh, also cleaned spark arrestor, looked dirty and can’t remember last time it was cleaned.
    Ordered the scan tool to help possibly pin point as i don't get any codes or beeps.
    Thoughts?
     
  2. techmitch

    techmitch Well-Known Member SILVER Sponsor

    May 1, 2008
    Chesapeake Bay, Middle River/Frog Mortar Creek MD.
    1999 270 DA
    Twin 4.3s W/Alpa I Gen II's

    2hours at wot?
     
    sbw1 likes this.
  3. Zim

    Zim Active Member

    162
    Jan 16, 2018
    2012 Sea ray sundancer 310
    Twin merc
    Yes, around 4k rpm. Did a 250 mile trip last yeary, 2 days, she ran all day both days at 3k-3.5K rpms, rough seas no issues. She doesn't get on plane till around 3.5k Book says 4.5-5k is max. Rev limiter controller.
     
    Last edited: Aug 13, 2019
  4. Espos4

    Espos4 Well-Known Member

    Jan 1, 2017
    Long Island NY
    2007 240 Sundeck
    350 MAG Bravo 3 W/DTS
    If you are only getting 4K rpm at WOT, there is something going on.

    Historically, With no codes stored you are looking at a fuel issue.

    Your pressure seems good. Did you have the injectors cleaned or replaced as part of the CF3 replacement?

    Insufficient flow from clogged injectors may not be evident from a fuel pressure test.

    Also, was the 38-39 psi fuel pressure measured at idle, or was that measured while operating at your current 2,000 rpm max engine speed?
     
  5. Espos4

    Espos4 Well-Known Member

    Jan 1, 2017
    Long Island NY
    2007 240 Sundeck
    350 MAG Bravo 3 W/DTS
    You now have 2 threads with the same info posted.

    I suggest that you close the other thread. Much easier to follow with all the info in one place.
     
  6. Zim

    Zim Active Member

    162
    Jan 16, 2018
    2012 Sea ray sundancer 310
    Twin merc
    My WOT is 4.5 -5k i believe, no issues in getting her there, i just happen to be cruising at 4k.

    Injectors were not cleaned. Orginal problem was no start, diagnosis was bad high pressure pump. Didn't feel like rebuilding, or replacing the pump so i opted to replace the module, and rebuild old one for spare. She started and ran fine After replacent and 2 hrs into trip that's when the loss of power happened. Crawled home with both engine at 2k, cruised around 8 mph.... long way home.

    Fuel pressure was taken at slip, docked and in neutral.
     
  7. Zim

    Zim Active Member

    162
    Jan 16, 2018
    2012 Sea ray sundancer 310
    Twin merc
    I can rebuild a carburetor, but i don't know how to close the other post. Thanks
     
  8. Zim

    Zim Active Member

    162
    Jan 16, 2018
    2012 Sea ray sundancer 310
    Twin merc
    Any last minute ideas before i start testing and swapping parts
     
  9. Spark600

    Spark600 Member

    60
    Dec 28, 2013
    Long Island NY
    2008 Sundancer with 496 SeaCore Bravo 3
    Kohler Generator
    Mercury dinghy
    496 SeaCore Bravo 3
    I had the same problem when I replaced my fuel module, The new fuel module had dirt in it from the factory that I did not no and when I started up the motor the dirt went into the fuel injectors.
    Had all fuel injectors test first before they cleaned them, They showed two were 80 % clogged and the other six were 20 % clogged
    Fixed my problem.
     
  10. Espos4

    Espos4 Well-Known Member

    Jan 1, 2017
    Long Island NY
    2007 240 Sundeck
    350 MAG Bravo 3 W/DTS
    Check the props and running gear, make sure you didn’t snag a line or some other debris.
     
  11. Zim

    Zim Active Member

    162
    Jan 16, 2018
    2012 Sea ray sundancer 310
    Twin merc
    So update for today; used pro tech scan tool, did a balance test and it showed several cylinders misfiring. 3 cylinders ( didn’t write them down though I know I should have) had over 200 misfires and the remaining showed about 30 or so. Pulled plugs, they looked ok, nothing out of the usual, maybe a few were little dark, but nothing that would make it obvious that it was the problem. Noticed one spark wire showed signs of rubbing. Pulled cap and rotor, looked ok, no signs of corrosion or moisture.

    Cheap insurance, I’ll order new cap, rotors and wires. Wondering if I should just as well replace the hall effect switch as well while I’m in there. Coil too, looks a little rough.

    I’ll let you all know how it goes.

    Oh, forgot, fuel pressure checked out ok. I guess my buddies fuel gauge tester was off a bit.
     
  12. Zim

    Zim Active Member

    162
    Jan 16, 2018
    2012 Sea ray sundancer 310
    Twin merc
    Thank you, that's the first thing i did
     
  13. techmitch

    techmitch Well-Known Member SILVER Sponsor

    May 1, 2008
    Chesapeake Bay, Middle River/Frog Mortar Creek MD.
    1999 270 DA
    Twin 4.3s W/Alpa I Gen II's

    Keep throwing parts at it, you'll get it sooner or later. $$$!
     
  14. Espos4

    Espos4 Well-Known Member

    Jan 1, 2017
    Long Island NY
    2007 240 Sundeck
    350 MAG Bravo 3 W/DTS
    You still need to check fuel pressure at your 2,000 rpm WOT.

    Also, some have experienced clogged injectors when installing the new fuel pump module. You could have paint chips from the original or debris in the new one that clogs the injectors.
     
  15. Zim

    Zim Active Member

    162
    Jan 16, 2018
    2012 Sea ray sundancer 310
    Twin merc
    Tracking, thank you. The original cool fuel module was the non painted (version 3?) And there were/ was no paint chips, also the filter looked good. Hasn't been changed in a few years so i feel confident that injectors are ok, as there was no contamination..... just a bad pump, but will check once i do the tune up.
     
  16. Zim

    Zim Active Member

    162
    Jan 16, 2018
    2012 Sea ray sundancer 310
    Twin merc
    Ah geez, your right, what was i thinking. I'll replace the 3 bad plugs and 3 sparkplug wires. Close call, spend a penny to save a dollar..... thank you!!
     
  17. Zim

    Zim Active Member

    162
    Jan 16, 2018
    2012 Sea ray sundancer 310
    Twin merc
    Update #2, pulled all the spark wires and 4 showed signs of rubbing with possibly arking. Didn't do the ohm test as it was obvious, so i ordered the basic items, wires, cap and rotor. ( for now). So, a story to tell here. Ordered the wire set from local marine parts store, (you think they would have the basic items in stock, but that's another story,) and would you know it, the coil wire is separate. Really? The 8 wires are 80 bucks and 1 coil wire half the size of the shortest sparkplug wire is another 38 bucks. What a racketeer thing. I want in!
    Would like to post pics of sparkplugs but for some reason it won't allow. Lettme try again.
    Side note, parts will be in tomorrow, hoping all goes well, was planning a cruise to the C&D canal from philly on Saturday..... wife is making a backup plan but i think i got this.....
     
  18. Zim

    Zim Active Member

    162
    Jan 16, 2018
    2012 Sea ray sundancer 310
    Twin merc
    This was #3 plug 9C5AF276-7F9E-4F79-9F74-662611EAC6ED.jpeg
     

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