Cummins Marine Diesel Repower Specialists Forums Cummins Marine Engines Port Engine trouble cold starting

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    Topic
  • #90691

    Seth Christman
    Participant
    Vessel Name: Layla Girl
    Engines: Twin 4BT 3.9L Cummins - 150HP
    Location: Virginia
    Country: USA

    I have a 1996 31′ Custom Carolina Express with twin Cummins 4BT 3.9 – 140 HP (both 1996 with 500 hours). I have had the boat a little under a year.

    A couple months ago, the port engine began having trouble cold starting (starboard engine starts on first turn of key). I would have to turn the key, 5-10 seconds each time, multiple times while having to rev the throttle to get her going, but it always starts (eventually) and once it is warmed up, it starts at first turn of the key. I do not believe the issue is a cold block (I live in Virginia and winter has been mild this year) because I was having the starting issue when the outside/water temps were above 70 F. I also have a bilge heater to keep the engine room above 40 F.

    I have changed air filter, and primary and secondary fuel filters. Oil filter is new and the appropriate amount of oil is in the engine. The battery voltage appears fine and the other engine will start right up. The port just cranks, like it is trying to start, but takes multiple attempts and i am afraid to burn up the starting solenoid.

    I am thinking maybe something to do with fuel supply or compression, but what are some other troubleshooting ideas that I can mess with to fix the cold starting issue?

    Thanks

Viewing 12 replies - 1 through 12 (of 12 total)
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  • #145290

    Mark Tripi
    Participant
    Vessel Name: Keeper
    Engines: Cummins 4BTA
    Location: Long Island NY
    Country: USA

    No, I measured voltage to the solenoid which it had, but none leaving to the heater. Bad solenoid.

    #144770

    whistlermark
    Participant

    PRE-HEATER

    Hi Mark

     

    we have 2x 250 hp BTA 3.9s 

    We have Port engine preheater does not work when cold, but when it has been run to temp the heater works just fine(flashes on for 5 seconds or so) . Was your s doing the same or was it not working at all?. We are trying to decide solenoids or the 3613547 sensor. I am leaning towards sensor and maybe when cold it is not low enough ohms to initialize the circuit/ ? Thank you 

    #93607

    Mark Tripi
    Participant
    Vessel Name: Keeper
    Engines: Cummins 4BTA
    Location: Long Island NY
    Country: USA

    Seth, I had a similar problem last season on my port 4BTA-250. This is a great place to get ideas of where to start. I ended up having compounded problems including one of the two air heater grids was not working. Not sure if you have these on your engine but mine has two solenoids that control them and one solenoid was bad. Fixed that and it was better but still not right. It felt like the engine lost it’s prime. Once it kicked off it would give a big puff of white smoke that smelled of unburned diesel. Earlier in the season I had noticed the slightest discoloring around injector 4. I pulled that injector (it was tough to get out) and it looked like something from the tar pits, never saw one like that before. I replaced that and it was way better.
    You need to check the simple stuff first, like do you have any air leaks in the system allowing it to lose prime. You have already changed fuel filters, and it was suggested to me that the lift pump could also be bad.
    Good luck, keep us posted.

    #93473

    Seth Christman
    Participant
    Vessel Name: Layla Girl
    Engines: Twin 4BT 3.9L Cummins - 150HP
    Location: Virginia
    Country: USA

    So it appears that the boat dealer was wrong about the Cummins being 170 HP as advertised, read the starboard engine plate and they are both 150HPs. Included some pictures below. Engine serial #44241811

    Exhaust system – raw water cooled with cast iron risers and flexible connection to four inch stainless steel pipes that exit through transom mounted fitting

    The black discharge looks to resemble burnt fuel/oil and only appears in port engine after cold start, not after warm start.

    Again, it only has trouble with the initial cold start, then fires right up each time after it gets going. I have heard of some old timers with their Chesapeake Bay Deadrises and old diesel engines spray WD-40 in the air intake to get a cold start going, but also heard this can be bad for the engine. Would you recommend this as a method to troubleshoot the problem (i.e., starts with WD-40, maybe its a fuel problem)?

    Anything else i can do to pinpoint the problem?

    Thanks

    #90784

    Tony Athens
    Moderator
    Vessel Name: Local Banks
    Engines: QSB 6.7 550 HP
    Location: Oxnard, CA
    Country: USA

    Some black “floating carbon” right at start up in pretty common some engines.. Seen it a lot ( if that is what he is referring to)………………………. It from the cold start (full rack) position of the injection pump during the start mode (like a choke) .. Are you sure your engines have never done that?

    My 1995 Dodge 12-Valve made a serious PUFF at start up, hot or cold….

    #90765

    Rob Schepis
    Forum Moderator
    Vessel Name: Tenacious
    Engines: 6BTA 5.9 330's - "Seaboard Style"
    Location: Long Island, NY
    Country: USA

    I should clarify that the black discharge is upon cold start only, not during running or idle, or even after warm start.

    A fuel sheen on the water surface upon cold start is not abnormal due to unburnt fuel from hard start and/or incomplete combustion. Can’t say I recall anyone refer to it as “black discharge” though. Does it look like a fuel sheen?

    #90749

    Tony Athens
    Moderator
    Vessel Name: Local Banks
    Engines: QSB 6.7 550 HP
    Location: Oxnard, CA
    Country: USA

    No 170HP either.. Post really good pics of the engines and a pic of the engine data tag ( or read the serial numbers)

    #90745

    Seth Christman
    Participant
    Vessel Name: Layla Girl
    Engines: Twin 4BT 3.9L Cummins - 150HP
    Location: Virginia
    Country: USA

    I should clarify that the black discharge is upon cold start only, not during running or idle, or even after warm start.

    #90744

    Seth Christman
    Participant
    Vessel Name: Layla Girl
    Engines: Twin 4BT 3.9L Cummins - 150HP
    Location: Virginia
    Country: USA

    Also, I notice black oil/burned fuel like discharge from port exhaust in the water every now and again. No smoke, just black discharge.

    #90743

    Seth Christman
    Participant
    Vessel Name: Layla Girl
    Engines: Twin 4BT 3.9L Cummins - 150HP
    Location: Virginia
    Country: USA

    Sorry, meant 170 HP each not 140.

    Will need to get pictures that show exhaust next time I am down at the boat.

    It will start up just fine after an hour or more cool down. The trouble occurs when I come back to the boat after it sits for a week or two.

    I can’t put an exact date on the cold start, probably around November time frame. Again, there have been some warmer days, 70F, where the issues have occurred.

    #90700

    Tony Athens
    Moderator
    Vessel Name: Local Banks
    Engines: QSB 6.7 550 HP
    Location: Oxnard, CA
    Country: USA

    Post some pics of your engines.. Let ID what you really have.. There never made a “140”.. Be sure I see the exhaust set-up on the slow to start engine.

    Once running and hot, if you shut down for and hour or so, how does it start then?

    When did this “not start easy thing” 1st show up?

    #90695

    John
    Participant
    Vessel Name: Puffin
    Engines: 270HP 6BTA
    Location: Watch Hill RI
    Country: USA

    Does you’re 4BT have a grid heater or glow plug (air pre-heater)? With a pre-heater shut down or not working, my 6BTA is difficult to start in cold weather (below 50 degrees).

Viewing 12 replies - 1 through 12 (of 12 total)

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