Cummins Marine Diesel Repower Specialists Forums New posts: Last three days

Viewing 11 topics - 1 through 11 (of 11 total)
    • Cummins Marine Forum Topics
    • Diagnosing Possible Head Gasket

      This topic has 8 replies, has 2 voices, and was last updated bypwrobert 8 minutes ago

      March 2, 2024 at 2:37 pm I installed a pair of 5.9L 6BTA 370’s back in 2019 which now have 520 hours.  Both engines seem to run well and do not smoke.  The Starboard one fills the Recovery bottle after running up on plane for a few minutes.  The engine never gets above 165-170F throughout the throttle range.  Quickly cools down to 150ish at 650-850 RPM.  But when I let it set it does not suck the coolant back into the expansion tank.  I see no milkyness in oil or …

      Started by: pwrobert in: Cummins Marine Engines


      8 Replies
      March 28, 2024 at 5:52 am If I were doing this upgrade again from scratch, I would use 1/4″ blue silicone hose instead of the 5/16″.  This because normally barbed fittings have beads or ridges larger than the ID of the hose they are fitting.  Example 3/8″ hose fittings have 3/8″ main body with barbs, beads or ridges 15/32″ (almost 1/2″) and other sizes do something similar. The Cummins overflow bottle fittings is 5/16″ OD of the …

      Last Post by: pwrobert posted: 8 minutes ago

    • Constant Torque Hose Clamps

      This topic has 2 replies, has 3 voices, and was last updated byRob Schepis 11 hours ago

      March 27, 2024 at 9:14 am Curious if there is any specification or guidance on tightening these hose clamps.  My impression is that the spring needs to have some give both to tighten and loosen to allow expansion.   Anyone have any advice vs just tightening them ‘tight’ like normal hose clamps.

      Started by: Zac Schramm in: Cummins Marine Engines


      2 Replies
      March 27, 2024 at 6:41 pm I don’t think my method is more technical or scientific but I use a good nut-driver with a nice quality handle and make them basically as tight as I reasonably can with this limited tool.  No wrenches  and no ratchets.  Just “nut-driver tight”  The only time I’ll resort to a socket and extensions on a 1/4″ drive is if something is harder to get to and then I am careful to only make ’em good and snug with the 1…

      Last Post by: Rob Schepis posted: 11 hours ago

    • 6BTA 330 Alternator Output

      This topic has 3 replies, has 2 voices, and was last updated byLee Essay 14 hours ago

      March 3, 2024 at 4:24 pm Looking into changing out the alternator on my 6BTA 330.  No current problems but was looking to upgrade it out of preventative maintenance as I believe it is the original from 2000.  I will keep the existing alternator on the boat as a backup since it still works.  My question is the current alternator is the OEM 19SI 105 amps.  I saw you have a 145amp option for a 19Si and wanted to know if there are any negatives or upgrades needed for going …

      Started by: Lee Essay in: Cummins Marine Engines


      3 Replies
      March 27, 2024 at 3:22 pm John,   A question for you.  Your boat name looks familiar.  Are you running a Nordic Tug?  

      Last Post by: Lee Essay posted: 14 hours ago

    • Cummins 6CTA8.3-M Heads

      This topic has 2 replies, has 3 voices, and was last updated byRichard Dodson 17 hours ago

      March 26, 2024 at 10:30 am I’m looking at purchasing a boat that has a pair of Cummins 6CTA8.3-M engines, CPL# 2960. At the very least I would follow the advice that is given here about propping the boat to the 450 fuel curve. My question is in regards to the heads. The engine SN’s are 46435824 and 46434682. Are these engines heads subject to the valve seat dropping out that I’ve been reading about or are they of a later vintage that I don’t need t…

      Started by: Curt Schultz in: Cummins Marine Engines


      2 Replies
      March 27, 2024 at 12:37 pm Hi, My ESN is below the TSB that Cummins issued in 2006 but above yours, you probably have the old heads.  The upgraded head # is: 4942463.  I had the misfortune of dropping an exhaust valve, around $22,000 to rebuild it. As a precaution, I swapped the head on the other side, around  $9,000. In addition I reduced the prop pitch 2″. This resulted in the desired 450 fuel burn to be 27.4 GPH at 2200 RPM which results in 18-19 Knots.   The sea…

      Last Post by: Richard Dodson posted: 17 hours ago

    • down on speed

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

      March 25, 2024 at 2:32 pm Hi all i have a 1999 Carver 530 with a pair of Cummins 6CTA 450HP engines and i am way down on speed. WOT is 2240RPMs and only delivers 16 knots … i have previously had it up to 22 knots… bottom of the boat is clean both engines have been rebuilt by Cummins… air filters all new… i am stumped on this tried trim tabs in all different positions with minimal affect… is there something i am missing..

      Started by: inmotion in: Cummins Marine Engines


      2 Replies
      March 27, 2024 at 5:24 am Like C;ark said, close to zero infor to work with.. Have you gone thru this article and not skipped anything ?–That would be the basic way to start. Understanding Low Power Troubleshooting        

      Last Post by: Tony Athens posted: 1 day ago

    • Cummins 4BTA 250 –Starboard engine WOT low/Power low

      This topic has 7 replies, has 3 voices, and was last updated byTony Athens 1 day ago

      March 26, 2024 at 4:01 pm Starboard engine not reaching WOT only hitting 2900, Port will make 3200rpm I’ve attached a spreadsheet with rpms, boost and egt values on both engines, please have a look. Testing was done with full load of fuel, water, 5 persons and Gear/food for a week.   Port engine 150hr/3year old major rebuild, runs great, little white smoke at startup, makes WOT 3200. Port engine WOT (3200) has steady even 30 PSI boost. Starboard engine 700 plus hou…

      Started by: boardsteez in: Cummins Marine Engines


      7 Replies
      March 27, 2024 at 5:21 am Have yopu gome thru the list in this article and not skipped anything? https://www.sbmar.com/featured-article/understanding-low-power-troubleshooting/    

      Last Post by: Tony Athens posted: 1 day ago

    • Hydraulic Second steering station question

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

      March 26, 2024 at 8:03 am Good Morning. I am adding a second steering station up in my tower. Ive plumbed all my hydraulics but I do not think I have them hooked up correctly. I am able to get the rudder to turn left and right but it feels like turning the bottom station with the boat off. it is very stiff. I am not sure in this diagram which station is suppose to be the 1st and second station.  my upper station is shown in a picture. The yellow tape line is tank, no tap…

      Started by: rick martinez in: Instrumentation & Electronics


      1 Reply
      March 26, 2024 at 6:16 pm You have orbitol power steering—————Before you added the second staion, was everything working right?  Did you make any other changes at the same time? Let’s get back where all worked right and figure all you did since then.    I want a clear pic of the original helm pump,  and the new one.      Look carefully at the drawing–are you hooked up exactly as shown between to two helm pumps ?

      Last Post by: Tony Athens posted: 1 day ago

    • New Boat, and Propping 1 2

      This topic has 30 replies, has 6 voices, and was last updated byShannon Ritzert 1 day ago

      October 19, 2023 at 9:18 am I recently purchased a new boat to me. Its a 31′ Bertram FBC. It has 2003 Yanmars 6LYA-STP 365 H.P. Each engine has right at 700 hrs on them. The gears are zf models 220A, ratio is 1.75:1 and she is propped at blade 22 x 24 x 1.75. I was told when lifted at the yard, that she weighs 18k pounds. It also refit by Cabrera Yachts in 2003. They tunneled the hull as well. This boat reminds me of Shooter that Seaboard refit. The old owne…

      Started by: Shannon Ritzert in: All Other Marine Diesels


      30 Replies
      March 26, 2024 at 7:44 am Tony, Here are the results of the prop scans Thanks     The prop shop suggests a 22″x20p 

      Last Post by: Shannon Ritzert posted: 1 day ago

    • ZF Hurth tag missing

      This topic has 2 replies, has 2 voices, and was last updated byFourWinnsMike 2 days ago

      March 25, 2024 at 7:38 am If the tag is missing from my transmission, how would someone tell what model V-Drive I have.  It is bolted to the following spec Cummins.  Model: 6BTA5.9.M2 Serial:4483T453 HP: 300HP Is there a certain profile.  I ask because I need a new coupler and I want to make sure I order the correct model for my transmission.   The shaft size is 1.5″ I can post pictures later today. Thanks.~Mike

      Started by: FourWinnsMike in: Marine Transmissions


      2 Replies
      March 25, 2024 at 7:22 pm Yes, it does have ATF.  Thanks Rob!!!

      Last Post by: FourWinnsMike posted: 2 days ago

    • SmartCraft malfunction

      This topic has 4 replies, has 2 voices, and was last updated byBill Quinlan 2 days ago

      March 22, 2024 at 9:48 am I’ve had a problem with the electronics on my Cummins QSB5.9-330HO.   It began with loss of throttle. Local Cummins replaced module and Medusa harness. Subsequently, I have lost throttle twice. The same tech scratched his head but couldn’t fix. Later I went to the boat and it had fixed itself. The 24 to 12 volt has blown its fuse twice. Most recently, the entire electronic controls shut down. The fuse was replaced and all powered up again. Why i…

      Started by: Bill Quinlan in: Cummins Marine Engines


      4 Replies
      March 25, 2024 at 5:43 pm The starter is 24 volt. 

      Last Post by: Bill Quinlan posted: 2 days ago

    • QSC 8.3 No Raw Water Circulation

      This topic has 10 replies, has 5 voices, and was last updated byBobby Harvey 2 days ago

      March 17, 2024 at 3:26 pm I had the boat out 0f the water for maintenance for about 2 months. Installed new raw water pumps, hoses, seacocks, strainers. (New bilge). When I tried to start one of the engines, I couldn’t get water to circulate (out of the exhaust). Water is getting to the pump and to the fuel oil cooler ok but no water beyond that. It was working fine before this. I tried priming the system with water first from the heat exchanger to mitigate possibl…

      Started by: Bobby Harvey in: Cummins Marine Engines


      10 Replies
      March 25, 2024 at 2:40 pm I am in the process of replacing both Aftercoolers. The old ones have never been serviced. Crushed them both trying to press them out of the housing. Able to save one housing. The port Gear Oil/Fuel cooler was plugged up. Hopefully that was the water circulation problem. I’ll find out when I get it back together. Both Gear Oil Fuel Coolers tested good. 100%. So, I can re-use them. I’m waiting on Seaboard to ship me the new Aftercoole…

      Last Post by: Bobby Harvey posted: 2 days ago

Viewing 11 topics - 1 through 11 (of 11 total)