Cummins Marine Diesel Repower Specialists Forums Cummins Marine Engines

This forum contains 1,268 topic and 7,401 replies, and was last updated by  Rob Schepis 4 hours ago.

Viewing 20 topics - 1 through 20 (of 1,267 total)
    • Cummins Marine Forum Topics
    • 2004 Cummins 6CTA 8.3 Oil Analysis 635 hours

      This topic has 5 replies, has 2 voices, and was last updated by Rob Schepis 4 hours ago

      October 18, 2019 at 6:16 pm Hey Guys , New to the forum but not to the automotive/marine industry. I am in the process of purchasing a boat with these Engines in it and Kubota Generator. The oil samples taken did not come back to be the best however this is some discrepancy on wether its just because its old oil and the motors were started multiple times over the last few months and not warmed up completely. So all those dry starts…….I am alittle concerned wit…

      Started by:  Josh Michels


      5 Replies
      October 20, 2019 at 5:56 pm Yes at startup, especially in colder weather. Underway once up to temperature you may see some under hard acceleration and pushing her over the hump Rob "Luck is the residue of good design."

      Last Post by:  Rob Schepis posted: 4 hours ago

    • 6BT fuel lift pump

      This topic has 1 reply, has 2 voices, and was last updated by Tony Athens 12 hours ago

      October 20, 2019 at 6:49 am Good morning. Question on the fuel lift pump on my 6BT. I have no starting issues, starts right up. Run just fun, so no issues there. I will be changing the fuel filter. Last Friday I actuated the hand pump lever on the lift pump for the heck of it. Seemed to move very free with no pressure as I would of thought it would have. Up and down like nothing was restricting the movement. My question: Is this normal or is there something wrong…

      Started by:  John Hobby


      1 Reply
      October 20, 2019 at 9:56 am The lift pump lever inside the engine rides on a CAM.. If the engine happened to stop with the “lever” on the cam, then the mechanical pump lever will feel totally limp–“NOTHING”.. Plus, if the vlever does work, than at best it’s pretty weak at best and slow to react or recover from the little bit it pumps.. An “outboard” type squeeze bulb does 3-4X the pumping with way less effort.. Tony Tony At…

      Last Post by:  Tony Athens posted: 12 hours ago

    • Rattling or Ticking Noise 6CTA (450 Diamond)

      This topic has 5 replies, has 4 voices, and was last updated by Steve 1 day ago

      October 18, 2019 at 1:17 pm My starboard engine has been running well. Actually, both have. No complaints with power, performance, or anything. However, when in the engine room today I began hearing a rattle or “ticking” sound. I looked around the engine itself and I didn’t see anything external that is loose that could be causing the rattle sound. So, naturally, I’m imagining the worst … valves. Can anyone offer a rough diagnosis from a video…

      Started by:  Steve


      5 Replies
      October 19, 2019 at 5:24 pm Thanks, guys. I’ll take a look around the engine room. I didn’t notice any soot down there recently but I’ll look more carefully. The boat was surveyed in March (when I bought it) and the exhausts were all in good shape then. But it can’t hurt to check. As to the questions by Phil: Howw many hours on the engine? 1400 What’s the service history? Pretty solid. Had the 1000 hour service done, valves adjusted aft least once. A few i…

      Last Post by:  Steve posted: 1 day ago

    • Sherwood M71 on 6BT

      This topic has 2 replies, has 2 voices, and was last updated by John Hobby 1 day ago

      October 19, 2019 at 1:28 pm Hey guys, Again, new to this boat and the 6BT 5.9M. Great motor! 440 hours. Preparing for spring. Just winterized yesterday. Check out the pic attached. Just want to hear it before I go there. Want to replace impeller. #1 Disconnect upper and lower hose. #2 Do I un-bolt entire unit from gear train and then remove the neck transition piece to replace impeller? No typical cover plate. #3 Then lash the gears back when replacing, all done?…

      Started by:  John Hobby


      2 Replies
      October 19, 2019 at 2:01 pm Hey Bill, kinda felt the same. Jus wanted to get a handle on it. Only one engine, thank god, two would kill me! John Hobby

      Last Post by:  John Hobby posted: 1 day ago

    • Raw water impeller tool

      This topic has 4 replies, has 3 voices, and was last updated by John Hobby 1 day ago

      October 14, 2019 at 5:03 am Hi to you all. Just was told about a impeller installation tool sold by impellertool.com. Guy said it was the bomb for install. Have not priced it yet but wonder if anyone has ever ordered and used this prior to me diving in. Cummins 6BT 5.9M. Sherwood 10615 impeller, key style. Thanks, John John Hobby

      Started by:  John Hobby


      4 Replies
      October 19, 2019 at 1:45 pm Hi Tony, I just posted another question regarding the Sherwood M-71 pump. Area around it is not bad but it seems to be the type of pump that needs to be removed in order to change impeller. No cover plate. So, any help would be great. Thanks so much. John Hobby Martha’s Vineyard, MA John Hobby

      Last Post by:  John Hobby posted: 1 day ago

    • engine stalling

      This topic has 3 replies, has 4 voices, and was last updated by Tony Athens 1 day ago

      September 24, 2019 at 4:07 pm I have a 1999 6CTA on my last three trip out my engine has stalled twice at 700 rpm, I was in a no wake zone going against the current and the third time I was underway going 2000 rpm 16 kt, and it suddenly shuts off. All three times the engine restarts without a problem and doesn’t stall the the rest of my fishing trip which are 40 kt miles, I have SMX Multi stage fuel filtration system, filter where changes this year so I donR…

      Started by:  John DiFilippo


      3 Replies
      October 19, 2019 at 11:32 am John, Maybe there is some confusion here as to what EXACT engine you have.. Post a few good pics of the injection pump side of the engine, AND an engine serial number… Tony Tony Athens Seaboard Founder Go here for the latest stuff we put together and share for all to see: https://www.sbmar.com/tonys-tips/

      Last Post by:  Tony Athens posted: 1 day ago

    • QSB 6.7 After cooler Flush

      This topic has 14 replies, has 6 voices, and was last updated by Paul McInnis 1 day ago

      September 20, 2019 at 12:47 pm My engine has about 350 hours and 2 1/2 seasons of use. I want to do the Barnacle Buster flush before I haul out for the season here in the Northeast(NH Seacoast). Many good points on this forum. I will be using the groco replacement cover for the in flow. I plan to remove the exhaust hose at the heat exchanger. My question is will that hose remove easily without damage and go back easily? Attachments:You must be logged in to access attached fi…

      Started by:  Paul McInnis


      14 Replies
      October 19, 2019 at 3:25 am Thanks for clarifying. My original inquiry was about doing a flush with Barnacle Buster as I am on a mooring without any way to have a fresh water flush set up. I am now convinced that I need to service the after cooler. Is this done by just removing the end caps or does the after cooler need to be removed from the engine.? In Tony’s last reply it shows the heat exchanger what is the suggested maintenance for it?

      Last Post by:  Paul McInnis posted: 1 day ago

    • 1999 6BTA 5.9 M-3 (older style) Heat Exchanger replacement

      This topic has 6 replies, has 3 voices, and was last updated by Tony Athens 2 days ago

      October 1, 2019 at 9:08 am Was seeing signs of the heat exchanger going over the last few month (expansion tank level, engine temps creeping up) and when the alarm started sounding after running at high RPMs after about 5 minutes (temps creeping above 200F) I knew it was time to pull it. Of course it’s the starboard engine, so the heat exchanger is outboard, real PIA to take out. Soaked it (estimate about 1/3 of tubes with at least some blockage) and then pressure …

      Started by:  Paul Hoffman


      6 Replies
      October 18, 2019 at 2:47 am Paul, Do yourself a favor–Since you really do not know the internal condition of the “other seawater components”, service them all.. Seawater pump (not just the impeller), the aftercooler ( put it on the bench and remove the core & service per my protocol), gear cooler, and then your heat-x…………………..Experience has shown conclusively over the past 25 years with this cooling system des…

      Last Post by:  Tony Athens posted: 2 days ago

    • head oil leak ??

      This topic has 1 reply, has 2 voices, and was last updated by Philip 2 days ago

      October 17, 2019 at 5:37 pm I have 2006 6ctas with 4,803 hrs in a 1978 42 chris craft sport fisherman.. salt water boat. My port motor seems to have an oil leak on the back of the motor at the bottom of the head. does not seem to be the valve cover or anything else. Is this a head leak or even possible. Am I missing something. It is not enough to cause and oil drop over a season compared to the starboard side. Oil consumption maybe 2 quarts over 100-150 hrs a season e…

      Started by:  Gregory


      1 Reply
      October 17, 2019 at 10:51 pm How about some good quality pictures of your engines from all sides in focus with enough resolution to zoom into things and have a look around. Include a closer up of your suspected oil leak area. Then we can hopefully help you… Phil

      Last Post by:  Philip posted: 2 days ago

    • QSC Aftercooler Part Identification

      This topic has 4 replies, has 2 voices, and was last updated by Corey Schmidt 3 days ago

      October 14, 2019 at 3:00 pm In the attached diagram, there is a ring between the two O-rings (#11). I’m not familiar with what that ring is so any help would be appreciated. My aftercoolers are on the bench now at a local shop as I could not get the cores out on my own. I just want to have all the required parts upon my reassembly of them. I do have the O-ring kits and more than enough lube from seaboard. Thanks, Tom Attachments:You must be logged in to access at…

      Started by:  Tom Bartolomei


      4 Replies
      October 17, 2019 at 9:41 am Of course we’ll need to see some clear pictures re: the pitting… We throw the silicone strips away as they are junk and always a hassle….. some people cannot live without them however… Corey Schmidt | VP, Operations | Seaboard Marine, Inc.

      Last Post by:  Corey Schmidt posted: 3 days ago

    • oil leak after raw water pump replacement

      This topic has 1 reply, has 2 voices, and was last updated by Rob Schepis 3 days ago

      October 16, 2019 at 12:41 pm Had an new SMX 1730 Seawater Pump installed on my starboard Cummins 6BTA-M3 about 6 weeks ago. When i hauled it last week, found out i had lost about one gallon of oil out of that engine, floating in the bilge. I’m not a mechanic….but was wondering if anyone who is could tell me if this install could possibly have led to the loss of oil into the bilge? Thanks. dwj

      Started by:  Dave Johnson


      1 Reply
      October 17, 2019 at 6:35 am Not much to offer without good pictures but maybe the football flange gasket was not replaced or was left out altogether? https://www.sbmar.com/product/smx-1730-seawater-pump-gasket-o-ring-kit/ Rob "Luck is the residue of good design."

      Last Post by:  Rob Schepis posted: 3 days ago

    • Wiring Size

      This topic has 6 replies, has 4 voices, and was last updated by Rob Schepis 4 days ago

      October 7, 2019 at 12:01 pm I’m going to install two (One for each engine) emergency shutoff switches in my tower. These would be used in conjunction with the redundant alarm panel I have mounted there, so I can shut the engines down quickly in an alarm situation. These would be normally closed/momentary open switches which I purchased at Seaboard. I plan on putting them in line on the”hold in” coil circuit for the fuel shutoff solenoid. They would be ene…

      Started by:  Philip Swofford


      6 Replies
      October 16, 2019 at 4:53 am Very nice and good move in pairing the 190F switches with the 160F tstats. Rob "Luck is the residue of good design."

      Last Post by:  Rob Schepis posted: 4 days ago

    • Cummins QSC 8.3 maintenance

      This topic has 8 replies, has 4 voices, and was last updated by Philip 5 days ago

      July 18, 2018 at 9:57 pm Hello everyone, this is my first time as I’m in the process of buying a new (to me) boat. I have some concerns and they may be unwarranted but I’m seeking advice and information. The boat is a 2008 and has the Cummins QSC 8.3 engines with approx 450 hours on them. I don’t know much about diesel engines but have quickly learned a lot because of this awesome site. I have an offer on the boat that is contingent on everything getti…

      Started by:  jeff vargas


      8 Replies
      October 15, 2019 at 5:54 pm 10 micron boat filter and the Fleetguard FF5488 on engine filter. The Racor can be messy, if your looking to upgrade you filter quality and capacity check out these…far superior and much easier to maintain. https://www.sbmar.com/product-category/fuel-systems/fuel-filtration-kits/ Phil

      Last Post by:  Philip posted: 5 days ago

    • Dumb move on the shifters!

      This topic has 6 replies, has 3 voices, and was last updated by Tony Athens 5 days ago

      October 3, 2019 at 3:23 pm Well, I did something stupid. I was cruising along at 2400 RPM and when I went to slow down I accidentally pulled the shifters out of gear instead moving the throttles. Seems to me that’s hard on the transmissions, but to make matters worse, without thinking, I instantly put them back into gear again (still at 2400 RPM)! I didn’t hear anything bad and there are not symptoms of anything haywire, but did I do any internal damage??? …

      Started by:  Mike Schmidt


      6 Replies
      October 15, 2019 at 11:39 am The MG506 is a really “good ol’ gear”, but is very light duty in comparason to what they’d put in off road equipment on a HP to HP basis.. A gear similar to a 506 would be rated to about 80-100HP in loader or tractor vs. 200+ HP in a boat. The “shock loads” just are not there is a boat, it’s all thru a “fluid medium”–The prop …. Tony Tony Athens Seaboard Founder Go here for th…

      Last Post by:  Tony Athens posted: 5 days ago

    • 6bta more power

      This topic has 2 replies, has 3 voices, and was last updated by donald roth 1 week ago

      October 6, 2019 at 8:05 pm Hi Tony and the team, I have a 6bta jwac engine rated at 270 hp with the Bosch pump. On the surface it seems as though the next hp increase in Cummins evolution came from going from jacket water to a raw water after-cooler. So the simple question is can you just swap out and re-plumb the aftercooler for more hp or does this just open up a can of worms? Paul

      Started by:  Paul Berkshire


      2 Replies
      October 13, 2019 at 1:34 pm Just modifying the aftercooler will not hot rod the motor, the fuel map is key to doing that. The injector pump and injectors and possibly other items related to increased internal loading/heat may be involved. Don’t forget that the drivetrain and propeller may also need upgrading with a power increase. Cummins has already done all the homework on this, and they offer their motors in a variety of configurations so that you can get what you ne…

      Last Post by:  donald roth posted: 1 week ago

    • My engines never turn over 1900 rpm in gear

      This topic has 6 replies, has 3 voices, and was last updated by donald roth 1 week ago

      October 7, 2019 at 12:27 pm Good afternoon together, I am since 2 Month the proud owner of a steel yacht build in 1974, repower in 2000 with ZF Transmission and 2 Cummins 6BT 180HP Rated. the engines were in the last 11 years never used and made in the years after the repower roughly 400 hours each. As i am new to boats in general and Cummins engines as well i have some questions. first i start with the most easy one. When we are cruising with the ship with RPMs around 190…

      Started by:  Oliver Heringhaus


      6 Replies
      October 13, 2019 at 1:11 pm If you are getting full travel on the throttle, and are not able to achieve same rpm both in forward gear and in neutral, your vessel is most likely overpropped. (Assuming bottom and running gear are clean) This may be intentional, especially on a big, heavy vessel with limited power. If the previous owner kept records, you might be able to look up prop specs to verify.

      Last Post by:  donald roth posted: 1 week ago

    • Zincs on 6BT 5.9M

      This topic has 6 replies, has 3 voices, and was last updated by Rob Schepis 1 week ago

      October 12, 2019 at 11:09 am Hi to all. New to the forum. Purchased a 1999 Eastern with 6BT 5.9M. My question, only one zinc in heat exchanger. That is what I have seemed to determine. Am I right? I have a PSS and I would assume they took the other zinc location and ran the cooling line. I am used to Yanmar ^LPA that had several zincs. Would appreciate any info. Love the Cummins, 392 hour when I bought the boat, got 440 now. Thanks John Hobby

      Started by:  John Hobby


      6 Replies
      October 12, 2019 at 3:15 pm John Hobby wrote: Hey Rob. One other thing. My parts guy has sold me a Camp 2E. Is that the correct length you think? Thanks. John Yes that would be “E2” John but will need to be trimmed to avoid bottoming out. See the second link I posted above, we talk about sizing and I posted a size chart. Rob "Luck is the residue of good design."

      Last Post by:  Rob Schepis posted: 1 week ago

    • Black smoke at cruise – 6BTA M3 -370 hp

      This topic has 9 replies, has 3 voices, and was last updated by Mike Uliasz 1 week ago

      September 16, 2019 at 6:19 am Port motor started smoking pretty good this weekend. Had slight black smoke a couple weeks ago. The boat seems over prop (2600 rpms wot at sea trail with slightly fouled running gear) to begin with. She had to work to get on a plane yesterday too. She got up to 2400 rpms and Cruised at 2200 rpms. 3000 rpms no load in slip. I did not run her without an air filter, but will try that next. The after-coolers have been serviced. Any additional …

      Started by:  Mike Uliasz


      9 Replies
      October 10, 2019 at 2:42 pm Keeping my fingers crossed, engine ran fine under no load in the slip but need to test run. Been rough and windy,, and now I’m out of town thru the weekend Mike Uliasz

      Last Post by:  Mike Uliasz posted: 1 week ago

    • Changing serpentine belt

      This topic has 13 replies, has 5 voices, and was last updated by Bill Stenger 1 week ago

      September 25, 2019 at 6:43 am Hello My mechanic changed our serpentine belts as part of the big service. One hour into our first trip out I could smell burning. Called him and he said that was ok as there is tensioner. 30 hours later belt broke. Called him again back and he could not explain the reason I checked all pullies and all fine apart from the one where the 2 belts are. All the screws were loose and the pulley was wobbly. I suspect this is the reason why the belt bro…

      Started by:  Olivier


      13 Replies
      October 10, 2019 at 12:58 pm Be prepared to press that bearing out and in with a press of sorts. it doesn’t just slip in or out. just a heads up. 1997 Sea Vee 28' CC

      Last Post by:  Bill Stenger posted: 1 week ago

    • Silicon in engine oil

      This topic has 2 replies, has 3 voices, and was last updated by Rob Schepis 1 week ago

      October 9, 2019 at 6:49 pm Cummins 6 CTA 8.3 450hp When I was in the process of purchasing this boat with twins it had 350 hours.I had the oil sample taken and the test results fine. After purchase I changeed the oil & filters using Rotella 15/40 and stored the boat for the winter. In the spring I added ,Seaboards Air sep system to both engins. Ran the boat about 175 hours and had the oil sampled before changing it. The samle came back with a critical reading for sili…

      Started by:  Rene Dupuis


      2 Replies
      October 10, 2019 at 6:38 am Was the pre-purchase oil sample and the recent ones taken by the same person using the same sampling methods and the same apparatus? Rob "Luck is the residue of good design."

      Last Post by:  Rob Schepis posted: 1 week ago

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