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Cummins Marine Diesel Repower Specialists › Forum community

Viewing 20 topics - 1 through 20 (of 5,617 total)
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    • Cummins Marine Forum Topics
    • Qsc8.3 low oil pressure

      This topic has 3 replies, has 3 voices, and was last updated byjoshkerwien 1 hour ago

      May 23, 2025 at 12:25 pm A couple weeks ago we removed heat exchangers and aftercoolers on a Searay L590 in Marina Del Rey equipped with 3 qsc8.3 600 engines. After we did standard oil change and sea trialed vessel with no issues. Yesterday the broker took the boat out and after running for about 20 minutes the low oil pressure alarm came on the mastercraft screen. We confirmed oil levels, swapped sensors, and put a mechanical gauge on the engine to confirm accurate oil…

      Started by: joshkerwien in: Cummins Marine Engines

      3 Replies
      May 27, 2025 at 10:49 am It’s a Vessel View 7 Mercury Marine version 5.0.43.574. I have confirmed readings with a mechanical gauge. Cold idle center engine is slightly above 20psi and other engines are at 60 psi. This drops once oil is warm and triggers the alarm.

      Last Post by: joshkerwien posted: 1 hour ago

    • QSM 11 Manifold Temperature and After cooler

      This topic has 4 replies, has 2 voices, and was last updated byRichard Geczi 2 hours ago

      May 10, 2025 at 8:36 pm Tony I have 2 questions. QSM 11 670 HP 2007 4100 hours Question 1. I just put in a new after cooler core due to a small saltwater leak out of my condensation drain (caught in time thank goodness) so my key question is you taught me how to service my after coolers back in 2012 and you liked the job I did so you asked me to send you photos which I did. So I failed to put the red RTV on the new core like I did back in 2012 and the new core didnR…

      Started by: Richard Geczi in: Cummins Marine Engines

      4 Replies
      May 27, 2025 at 9:18 am So my Port manifold temp was showing 89 prior to replacing my aftercooler core, than jumped to 107-112  afterwards. I switched the temp air sensor from the Stb engine to the Port side and it now stays at 89 after a long run but now the Stb engine shows 107-113 after a long run ( it creeps up). I ordered another sensor and the same thing, Stb engine shows 107-113 after a long run but the port eng stays at 89?????. They both start out at 89 for a …

      Last Post by: Richard Geczi posted: 2 hours ago

    • Alternator replacement 11si to ??

      This topic has 0 replies, has 1 voices, and was last updated by 5 hours ago

      May 27, 2025 at 6:54 am Alternator on my 1988 5.9 6BT is intermittent.  My tach runs off the alternator ( 3 wire).  Pulled it and its a 63amp, and I believe its a delphi 11si. Found a NOS 15si online that I ordered.  Looks identical, has the 3 wire hookup.  It is however slightly larger in diameter.  Can it be adapted?  Or will I need a new belt and everything? Is the 220hp alternator that SB marine sells here a direct replacement for what I had?

      Started by: Matthew Libby in: Cummins Marine Engines

      0 Replies - Can you Help? ...be the First to Respond!

    • Resealing high pressure lines on CAV Pump?

      This topic has 0 replies, has 1 voices, and was last updated by 5 hours ago

      May 27, 2025 at 6:50 am I have twin 5.9 6BT’s in my 43 Albin (new to me).  They both have the Lucas/Delphi CAV pump.  I have a pretty significatnt leak from the port engine.  I have traced it down to one area on the CAV pump. It appears to be leaking from one of the high pressure lines where they attach to the pump.  Looking at the back of the pump, I believe it is the 3 oclock and 5 oclock positions that area leaking.  Really hard to get to. I bought a longer fl…

      Started by: Matthew Libby in: Cummins Marine Engines

      0 Replies - Can you Help? ...be the First to Respond!

    • 6BTA5.9-M3 // Chasing Oil Leak AFT PAN

      This topic has 2 replies, has 2 voices, and was last updated byCharlie Hodge 8 hours ago

      May 26, 2025 at 2:59 pm Hello, I am chasing a small oil leak on my 6BTA5.9.  It seems to be coming from the AFT port & starboard oil pan area, where it meets the transmission.  Transmission was pulled and rebuilt a year ago, with 3 clean oil reports. Current Engine hours 5200. Engine Serial Number  4604780 These photos are immediately after 3 hour run today, at 2200 RPM.  My dipstick is at the lower mark and I need to had about 3 to 5 ounces of oil every 12-hours o…

      Started by: Charlie Hodge in: Cummins Marine Engines

      2 Replies
      May 27, 2025 at 3:07 am Thank You Tony   Charlie Hodge Baltimore AT34-11

      Last Post by: Charlie Hodge posted: 8 hours ago

    • 6CTA 480 replacement head casting number

      This topic has 2 replies, has 3 voices, and was last updated byRichard Dodson 21 hours ago

      May 5, 2025 at 11:25 am I am in the process of having the heads replaced on my 6CTA 480 M-4 engines to avoid the famous dropped valve seat issue.  According to Cummins the replacement upgraded head part number is 4942463.  The heads the mechanic is currently installing have a casting number of 3936153.  The mechanic explained the part number on the boxes from Cummins are 4942463 and the casting number on the head is not relevant.  Out of an abundance of caution I want …

      Started by: William Michael Kelly in: Cummins Marine Engines

      2 Replies
      May 26, 2025 at 2:16 pm I changed both of my heads after a valve seat drop. The crate had the new part number, but the casting number was different. RG Dodson

      Last Post by: Richard Dodson posted: 21 hours ago

    • QSC 8.3 will not start, will not crank

      This topic has 7 replies, has 5 voices, and was last updated byRichard Dodson 21 hours ago

      May 11, 2025 at 1:59 pm I have a 2003 Sea Ray 460 with 2020 QSC 8.3’s approx. 65 hrs to date. Port engine will not start, will not crank. Can hear solenoid engaging and have checked solenoid. It seems to be fine. Could the issue be with the mag switch coil? Thank you for any help!

      Started by: Peter Brennan in: Cummins Marine Engines

      7 Replies
      May 26, 2025 at 2:08 pm Get a remote starter switch, Autozone or Amazon. Read how to hook it up, basically the 12 V on the solenoid to one of the small terminals. If one doesn’t work try the other. At the same time have someone press the start switch at the helm.  I had to do that when my mag switch died. RG Dodson

      Last Post by: Richard Dodson posted: 21 hours ago

    • Gear Oil Cooler drain-port bolt size?

      This topic has 3 replies, has 2 voices, and was last updated byTrevor 1 day ago

      May 25, 2025 at 8:22 pm I discovered a water leak from the saltwater side drain-port on my port side gear oil cooler and had to replace the K&N filter below it.  It appears like the drain bolt might be damaged, and partially broken off inside the housing.  Is anyone familiar with what size bolt this is?  I might need to remove the cooler, and tap the threads?  It also appears that my particular cooler doesn’t have zincs, unless this drain bolt doubles as a zi…

      Started by: Trevor in: Cummins Marine Engines

      3 Replies
      May 26, 2025 at 12:05 pm I now realize the 00 pencil zinc has a 1/8″ plug.  Would it be better to use a 00 zinc, or just a 1/8″ plug?  This boat is somewhat new to us and I’m not yet familiar with the gear oil cooler.  Thanks  

      Last Post by: Trevor posted: 1 day ago

    • QSM11 High Oil Temp

      This topic has 3 replies, has 2 voices, and was last updated byTony Athens 1 day ago

      May 25, 2025 at 2:29 pm For a little history this is my 6th season with the boat.   It is a 2011 Searay 520 Sedan Bridge with QSM11s.   I bought it with around 600hrs.  I had full major service done on raw water cooling system by Cummins tech 5 yrs ago at around 700 hrs. There were no signs of issues so the heat exchangers and intercoolers were cleaned and reinstalled.     The exhaust manifolds were not leaking at the time and they were resurfaced and reinstalled.   I …

      Started by: Jeremy Gavin in: Cummins Marine Engines

      3 Replies
      May 26, 2025 at 6:24 am Just so you understand where I am going with this—–the front sump OP design on the QSM11 is very sustable to over filling and the crank “whipping” oil  causing the oil to get measurebly hotter………Dip stick markings need to checked–Just putting in 8 gallons  is not the way this needs to done until the dip stick is calibrated correrctly.   It’s all about what is in  the oil pan, engine off &…

      Last Post by: Tony Athens posted: 1 day ago

    • 6CTA M3 low Idle

      This topic has 1 reply, has 2 voices, and was last updated byTony Athens 2 days ago

      May 25, 2025 at 9:00 am I have an issue with my starboard motor is now idling lower than the port side by an approximately 50 to 75 RPM. I have clean the air filters, Changed both fuel filters with no improvement. Starboard engine idles rough probably because of the lower approximately 600 RPM. Acceleration has a vibration. But once the boost kicks in it runs fine I get full RPM at least 2700. Does not seem to improve once it’s warmed up. In neutral revving it up to ap…

      Started by: Steve in: Cummins Marine Engines

      1 Reply
      May 25, 2025 at 10:15 am Post pics like the attached———–clear & in-focus Seaboard Founder & President

      Last Post by: Tony Athens posted: 2 days ago

    • 1999 Cummins 6BTA M3, high oil pressure

      This topic has 1 reply, has 2 voices, and was last updated byTony Athens 2 days ago

      May 24, 2025 at 6:43 am Not too long ago, on engine start up, my stbd engine oil pressure went right to 80 PSI at idle.  The pressure came down a bit (to ~ 60PSI) after the engine warmed up).  Began trouble shooting.  Replaced Sender – no change, had gauge checked by Faria – no change.  Suspecting either 1) wiring issue between sender and gauge, or 2) oil pressure regulating valve. (saw this old post, unfortunetely it died with no ‘solution’ not…

      Started by: Paul in: General Discussion

      1 Reply
      May 24, 2025 at 4:36 pm The absolute last thing on the list is the valve.. IMO, don’t touch it. Plastic tubing ???????  Use a 0-200 PSI gage, liquid filled on a small hyd hose. Gauges are most accurate in the center of the scale. Seaboard Founder & President

      Last Post by: Tony Athens posted: 2 days ago

    • 2002 Cummins 480 CE Data Link Inactive Message

      This topic has 3 replies, has 3 voices, and was last updated byluislopezm1997 4 days ago

      May 30, 2022 at 2:57 pm Hi everyone, over the weekend I lost my port side engine to a “data link inactive” message displayed on my Cummins display. Engine will now crank and not start. The pcm connectors are clean and tight, the big rectangle serial connector at the back of the engine is clean and tight, that harness has the twisted wires all the way up to the display. I found a reset breaker on the engine that had a broken wire fixed that, that has battery voltage now…

      Started by: Jon Tisdale in: Cummins Marine Engines

      3 Replies
      May 23, 2025 at 9:21 am Hi Jon. Ive ran into the same issue. Were you able to fix this.

      Last Post by: luislopezm1997 posted: 4 days ago

    • QSB6.7 military (CAMO) belt – is it stretchy?

      This topic has 8 replies, has 3 voices, and was last updated byJon Fitch 4 days ago

      May 20, 2025 at 8:47 am This is related to my prior post about alternator upgrades, but perhaps a subject on its own: there appears to be a military version of the QSB with an extra idler, description is “large alternator” which is exactly what I want to do. It suggests that the military (or Cummins) thought something extra was necessary for a high output alternator. Is the “CAMO” belt a stretchy or conventional polyV? Is the extra idler a sprin…

      Started by: Jon Fitch in: Cummins Marine Engines

      8 Replies
      May 23, 2025 at 8:22 am OK, an ~8% increase in contact area, so I could go from 100A output to 108 hypothetically. That’s why I thought it was a marginal improvement, and wondered if belt surge or some other problem were the target. But I think the engine turns CC wise, so the run between the alternator and the damper is the tension side, not likely to surge, at least in a normal non-stretchy belt.

      Last Post by: Jon Fitch posted: 4 days ago

    • qsb 5.9 alarms

      This topic has 2 replies, has 2 voices, and was last updated byTony Athens 4 days ago

      May 18, 2025 at 6:22 am I have twin qsb 5.9 ( 2008)  w about 1k hours .. Have had them for 7 years .. do all my annual maintainence ( oil .. tranny , all filters , zincs  etc) , Boat runs great. Last season i would be cruising ( 2400- 2500 rmp ) and out of nowhere would get a screetching alarm ..all numbers looked good normal , temp boost , pressure etc .. nothing out fo the ordinary.  Head scratcher , boat would continue rolling good ( with the alarm sounding ) until …

      Started by: raymond gonzalez in: General Discussion

      2 Replies
      May 22, 2025 at 4:17 pm Post a clear picure of your helm station/ displays / insrruments you monitor the engines with Turn them on for the picture Seaboard Founder & President

      Last Post by: Tony Athens posted: 4 days ago

    • Removing Smartcraft Harness

      This topic has 2 replies, has 3 voices, and was last updated byJohn 6 days ago

      May 6, 2025 at 3:45 pm Hello Recently picked up a new boat to me which is running Twin qsc8.3. When I got the boat the smartcraft system was displaying all kinds of inaccurate data. Instead of going down that rabbit hole I decided to bypass the smartcraft and go J1939. I installed a Veretron VMH70 which displays both engines. (ill try and post a pic) I wired the VMH70 via the J1939 data plug on the side of each engine and ran that to the helm. Question is Im a little …

      Started by: Craig Larson in: Cummins Marine Engines

      2 Replies
      May 20, 2025 at 4:31 pm Why bother?  If all other stuff works, just leave it. I have a Fireboy-Xintex system that I’d think is tied into all that wiring so maybe worth leaving it if you have the same. I like the system you put in though. Interesting. Good luck

      Last Post by: John posted: 6 days ago

    • QSC 8.3 intermittent lift pump

      This topic has 5 replies, has 3 voices, and was last updated byTony Athens 1 week ago

      May 18, 2025 at 12:28 pm QSC 8.3 600. It seems like the fuel lift pump is turning on intermittently with key-on.  It will run a few times in a row, then not run a few times in a row.  I don’t see a pattern. Fuel pressure gauge indicates 82.24 psi with key on, not running.  I found the 2 pin plug for the pump below the ECU and disconnected/ reconnected it. Also intermittently I will get a warning beep at key on when the pump hasn’t run. What would cause this?

      Started by: Brad Arrington in: General Discussion

      5 Replies
      May 20, 2025 at 8:13 am I stand corrected on the operation of the QSC lift pump.. I thought the QSC an QSL had the same elec pump software. They do not. The QSC pump runs all the time,  where as the QSL elec pump only runs during the starting/priming mode.   Seaboard Founder & President

      Last Post by: Tony Athens posted: 1 week ago

    • CTA8.3 optimal fuel burn/longevity question

      This topic has 1 reply, has 2 voices, and was last updated byRob Schepis 1 week ago

      May 19, 2025 at 9:12 am My 55′ LOA, 46′ waterline, 30 ton semi-displacement, fin stabilized trawler (no hard chimes) is powered with twin 6CTA8.3 vintage 2000.  Boat reaches hull speed (just under 10kts) at around 1600rpms.  With tabs down will cruise at 15kts at 2350rpms.  Obviously fuel burn significantly higher at 2350.  Question to forum:  thoughts on balancing fuel economy with optimal engine load/longevity.  

      Started by: David in: Cummins Marine Engines

      1 Reply
      May 19, 2025 at 1:24 pm There’s a few variables – engine loading (proper propping) and total fuel burned.  Hull speed would be best for the engine life and your wallet.  A few good articles: Engine Life vs. Engine Loading Continuous Duty – A Different Perspective Rob "Luck is the residue of good design."

      Last Post by: Rob Schepis posted: 1 week ago

    • Pre-Purchase mechanical inspection in winter

      This topic has 3 replies, has 3 voices, and was last updated byDesmond Ashcroft 1 week ago

      October 29, 2020 at 7:20 am I am considering purchasing a boat powered by twin 450 Cummins engines, model year 2000. The boat is up north and is put away in a heated building for winter storage. Is it possible to evaluate these engines without running them? I would be looking for major issues that would have to be fixed before closing on the boat.

      Started by: mike.olson in: Cummins Marine Engines

      3 Replies
      May 19, 2025 at 1:25 am Great question and definitely smart to think this through before closing. While it’s ideal to run the engines for a full evaluation, a pre-purchase mechanical inspection can still be very informative even during winter storage. A good surveyor or marine mechanic can check for signs of wear, leaks, corrosion, compression issues, and overall maintenance condition by inspecting fluids, filters, belts, hoses, and using borescope or diagnostic tools.…

      Last Post by: Desmond Ashcroft posted: 1 week ago

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Viewing 20 topics - 1 through 20 (of 5,617 total)
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