Cummins Marine Diesel Repower Specialists Forums Cummins Marine Engines 6bta 5.9 CPL 970 won't exceed 1800 rpm

  • Creator
    Topic
  • #75903

    Dave Weber
    Participant
    Vessel Name: Blue Diamond
    Engines: 6bta 5.9 m2
    Location: Cincinnati Ohio
    Country: USA

    Hi Guys,

    New to forum and need some help.

    I’m hoping you can help me out with a problem I am experiencing with my boat engine, Cummins 6BTA 12 valve 5.9 M2 EP-9 injection pump. The problem I’m having is with the port engine which fires up without hesitation and runs great up to about 1800 rpm at this point I can continue advancing the throttle but there is zero response, this all happens under load. In the neutral position the engine functions normally and will rev up to 3000 rpm. The starboard engine performs normally and both are 1992 vintage with approximately 1250 hours on each. Has proper after coolers.

    I acquired this boat in August of 2018 and the engine problem was present at that time so I am unable to give you any operational history. Here is the details of the engine:

    ESN: 44724555

    MARKETING MODEL NAME: B5.9M (300)

    BUILD DATE: 02 MAR 1992

    FUEL PUMP PART# 3919762

    MARKETING ENGINE CONFIG. :D403017MM12

    TECHNICAL ENGINE CONFIG. :D403017MX02

    CPL# 970

    300 HP @ 2800 RPM

    The following has been done in troubleshooting this problem:

    Primary fuel filter cleaned and element replaced

    Engine fuel filter replaced

    Pressure check of port lift pump taken after filter and before PE-9, 15 psi idle to 20 psi @ 2400

    Pressure check of starboard engine produced identical results and it runs great.

    1000 rpm under load at dock 15 psi both engines individually tested.

    Over flow/return valve removed and cleaned, ball and spring seemed ok. Air bled from pump

    Throttle linkage and function checked along with throttle stops, both stations normal (boat equipped with ZF Micro-Commander controls with synchronization)

    12 volt trombetta shutoff valve removed and serviced per sbmarine how-to.

    Shutoff arm checked and springs to run position when solenoid is retracted

    Aneroid tube to intake manifold removed and checked

    I was able to read the governor number on the starboard engine which showed Nippon Denso 190300-2950, I was not able to read the port do to position of the plate. (I am able to get it but will require substantial effort and it’s the same governor).

    Engine is one of two in a 1993 Bluewater Costal Cruiser 5400 (BTTL54237J293) Trans TRM25A #225-625L Prop Federal EQVI Quad 24 dia. 26 pitch Heavy Cupped 1.5 bore.

    Thanks in advance for your help. (I would bring the boat to sbmarine but a long trip from Ohio River mile 498!)

    Dave

Viewing 10 replies - 21 through 30 (of 30 total)
  • Author
    Replies
  • #76108

    Dave Weber
    Participant
    Vessel Name: Blue Diamond
    Engines: 6bta 5.9 m2
    Location: Cincinnati Ohio
    Country: USA

    Hi Bill,

    If the aftercooler is plugged I think that would result in the engine sucking hot air and reducing HP but would that cause it to be ok up to 1800 RPM and no more? There are plenty of engines around that run without aftercoolers at lower HP.

    I’ll test the intake temperature on both engines with my IR tester and see if there is a big difference. Anyone know what optimal temperature reading would be?

    Thanks

    #76097

    Bill Stenger
    Participant
    Engines: 250 Hp 6bt M1
    Country: United States

    My guess is that Tony is questioning whether there is a clogged after cooler on the misbehaving engine.

    #76004

    Dave Weber
    Participant
    Vessel Name: Blue Diamond
    Engines: 6bta 5.9 m2
    Location: Cincinnati Ohio
    Country: USA

    Tony,

    Will do, obviously this will take some time and a big project for me (I’m 72). What’s your thought process on the problem and what are we trying to resolve with the aftercoolers other than good maintenance? I already checked the boost line between the aneroid and the intake manifold and it was clear.

    No black smoke present.

    Thanks again for your help.

    #75993

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

    #1—————Both aftercoolers on the bench.. Take completely apart and service per my protocol

    #2—————-While you are doing that, remove the small boost line from the suspect engine and be sure that on both ends nothing is clogged–Especially on the engine connection side.. This line sends boost to the aneroid on top of your ND pumps———————- NO BOOST = NO FUEL= NO POWER– You said no black / dark smoke, correct?

    #3—When the aftercoolers is on the bench and apart–Take GOOD PICS, as in the pics that I have posted about them on this web site.. I want to see all..

    Report back..

    Tony..

    #75986

    Dave Weber
    Participant
    Vessel Name: Blue Diamond
    Engines: 6bta 5.9 m2
    Location: Cincinnati Ohio
    Country: USA

    Test of starboard return hose

    The starboard test was a little easier initially, it’s a shorter hose than the port, about the same resistance after the initial blow. gurgling noise present at both tests. No fuel or drips present for both when hose was disconnected.

    #75954

    Dave Weber
    Participant
    Vessel Name: Blue Diamond
    Engines: 6bta 5.9 m2
    Location: Cincinnati Ohio
    Country: USA

    Photos and results of return line test

    Hey Tony,

    I blew thru the port (problem) engine fuel return hose and it was real hard at first like it was restricted but may have just been overcoming resistance to fuel in the line. Once that was cleared still not real easy to blow thru and made gurgling sounds as I blew. I did not do the starboard engine yet for comparison but will try and get it today.

    Here are some photos of the starboard engine pump and after cooler and one of the port engine from above.

    No maintenance history on the after coolers only that they have spent their life in fresh water. Looked clean when I drained them last fall to winterize.

    #75939

    Dave Weber
    Participant
    Vessel Name: Blue Diamond
    Engines: 6bta 5.9 m2
    Location: Cincinnati Ohio
    Country: USA

    Thanks for your input, running gear is fine and works perfect up to 1800 RPM. No vibration or problems associated with shaft, seals and props.

    #75938

    Dave Weber
    Participant
    Vessel Name: Blue Diamond
    Engines: 6bta 5.9 m2
    Location: Cincinnati Ohio
    Country: USA

    Tony,

    The parts manual for the engines shows the following:

    Base fuel pump option fp97220

    Part # 3919762

    Remarks

    Nippondenso “EP9” type (non certified) boost control fuel pump for 300 BHP turbocharged seawater aftercooled b Series engine at 2800 RPM high output rating for 6BTA5.9 M2 engine. Has manual actuate to run fuel solenoid and 2.0mm tubing. Reference: CPL #0970 with FR9647.

    I will try and get some photos although very confined area so I’ll have to break in sections. I have seen identical engines for sale on line. As far as boost goes, I have not checked. I’ll have do some reading on “how to”.

    I will check the fuel return line to make sure it is clear. Aftercoolers are the same as the last one pictured on your aftercooler types tip. I will get details on it and reply. It’s the one with the rounded front made in Great Britain.

    Engine info says series 403 if that’s of use.

    Thanks for your help!

    #75927

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

    Dave,

    You have done a lot at this point and eliminated most all the common things, but let’s now do more—

    Can you remove the return fuel line on that engine and blow thru it all the way to the tank? Compare to the other side. Let make sure it is 100% open to the tank, even if submerged and you make bubbles when you blow into it.. It should never take more that 1-2 PSI to clear it.

    Have you checked boost on both engines ? Super important

    Post a good picture of your injection pumps ( both) — Need to ID early or late vintage EP9 CPL970.

    Aftercoolers— Post pics of both– Need to ID the VINTAGE / type–Service history?

    Actually good picture of all would be nice. Remember we are dealing with 26 yr old engines .

    Tony

    #75919

    Leander Landrum
    Participant
    Vessel Name: 2001 Tiara 3500 Open
    Engines: 2x Cummins 6BTA 370
    Location: Tacoma WA
    Country: US

    Have you checked your prop, cutlass bearings and shaft/shaft seals?

Viewing 10 replies - 21 through 30 (of 30 total)

You must be logged in to reply to this topic.