Poor engine performance when cold

Discussion in 'Gas Engines/Drives/Transmissions/Props' started by bigriver 74, Jun 25, 2018.

  1. bigriver 74

    bigriver 74 New Member

    5
    Jul 10, 2015
    NW Wisconsin
    1998 Sea Ray 190 with 5.0 L engine that was replaced 2009 with rebuilt engine
    5.0 L Mercruiser Alpha 1 engine
    I have a 1998 sea ray 190 bowrlder with a 5.0L mercrusier engine rebuilt in 2009. Pulled it out of winter storage and launched it. New gas in tank and new water separator filter installed. Started right up. All pressures good. Reved the engine out of gear, ran well. Placed in gear and gave it full throttle. Could not get above 2500 rpm and engine sounded like it was not getting any fuel. Backed off on throttle and idled for about 10 minutes. Engine temp came up to 170. Gave it full throttle. Higher rpms this time, then some surging and finally reached higher rpm to place boat on plane. Ran boat for about 60 minutes...never missed a beat. WOT was 4200 rpm and 46 MPH. Slowed down to idle speed and gave it the gas. Came right up on plane and ran well.
    The following day went through the same routine and had same results, no rpm or output until reaching 170 temp. Then a surging and then good performance. Question: what is going on. This has not been a problem until this year. Originally thought of water in gas that is why I changed the water separator filter. Any insight anyone can provide would be great.
    Thanks,
     
  2. Strecker25

    Strecker25 Well-Known Member SILVER Sponsor

    Nov 20, 2014
    Rochester, NY
    1998 290 Sundancer
    Twin 5.7EFI/Alphas, Kohler 4kw
    Carb or fuel injected? Could be a sticky choke if it’s carbed, that eventually pops once it gets hot enough.
     
  3. Stee6043

    Stee6043 Well-Known Member

    Jun 1, 2015
    West Michigan
    1997 Sundancer 400
    Past:
    1999 Sundancer 340
    7.4L Gassers
    I'd suggest it's normal for a motor to be sluggish if you don't give it time to get up to operating temp??? Perhaps that's a silly suggestion. But I don't know many folks that would willingly rip WOT on a cold motor....
     
  4. Espos4

    Espos4 Active Member

    379
    Jan 1, 2017
    Long Island NY
    2007 240 Sundeck
    350 MAG Bravo 3 W/DTS
    Carbureted motor......choke may need adjustment

    Fuel injected motor......check the coolant temperature sensor values.
     
  5. bigriver 74

    bigriver 74 New Member

    5
    Jul 10, 2015
    NW Wisconsin
    1998 Sea Ray 190 with 5.0 L engine that was replaced 2009 with rebuilt engine
    5.0 L Mercruiser Alpha 1 engine
    Fuel injected
     
  6. bigriver 74

    bigriver 74 New Member

    5
    Jul 10, 2015
    NW Wisconsin
    1998 Sea Ray 190 with 5.0 L engine that was replaced 2009 with rebuilt engine
    5.0 L Mercruiser Alpha 1 engine
    Always let motor idle for at least 5 min so not really cold so not ripping the throttle as you assume. Thanks I think...
     
  7. Stee6043

    Stee6043 Well-Known Member

    Jun 1, 2015
    West Michigan
    1997 Sundancer 400
    Past:
    1999 Sundancer 340
    7.4L Gassers
    5 minutes isn't enough to achieve operating temp in most boats I've been around. You also stated you had to troll for 10 minutes to get it up to temp...."cold" and "operating temp" are worlds apart I think?

    I'm not a mechanic. That's why I use words like "suggest" and "perhaps". Your mileage may vary. Best of luck.
     
  8. scoflaw

    scoflaw Well-Known Member SILVER Sponsor

    Aug 10, 2011
    cape cod mass
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    Could be loose or dirty wire connection. EFI engines are sensitive to a steady supply of correct voltage and the ground path is equally important as well. Check your alternator output and load test the battery.

    As mentioned check what your CTS is doing. This problem has nothing to do with the warm up time. The ECM is made to compensate fuel and timing for a cold and hot engine.
     
  9. bigriver 74

    bigriver 74 New Member

    5
    Jul 10, 2015
    NW Wisconsin
    1998 Sea Ray 190 with 5.0 L engine that was replaced 2009 with rebuilt engine
    5.0 L Mercruiser Alpha 1 engine
    Ok help me out here...what is CTS and ECM? Have an idea but if you could define for me that would be wonderful.
     
  10. Espos4

    Espos4 Active Member

    379
    Jan 1, 2017
    Long Island NY
    2007 240 Sundeck
    350 MAG Bravo 3 W/DTS
    CTS = coolant temperature sensor. A 2 wire sensor on the thermostat housing.

    ECM = engine (or electronic) control module. The metal thing bolted to the inboard side of the port exhaust riser with several wire harness connectors attached to it.
     

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