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- Cummins Marine Forum Topics
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Engine loading
This topic has 8 replies, has 4 voices, and was last updated by
1 year ago May 23, 2022 at 2:23 am Hello, There are a lot of questions/explanations on the web and on this forum regarding the engine loading. All is about links between rpm, gph versus cummins official table, load @ propeller and some more parameters… In fact I wonder if we just can’t say that all is OK when the engine hit the max rated RPMĀ @WOT andĀ whatever the load of the boat. Is it a too simplistic assumption?Ā LL Ā
8 RepliesMay 24, 2022 at 8:12 am OK.Ā My cruise range is 2200-2400 rpm.Ā I feel my engines do not struggle at that speed. Indeed 2700 always seemed to me much too high for a constant cruise operation despite the -300 rpm RPM convention for a 2800-3500 max rpm rated engine . Concerning my engines consumption, the first measures tend to show that I am 5% (port) to 8% (starboard) above the propeler demand curve. I need to make more accurate measurements as it is not easy to set th…Last Post by:
posted: 1 year ago
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Cummins QSB 6.7 tensioner pulley
This topic has 6 replies, has 2 voices, and was last updated by
1 year ago May 21, 2022 at 1:33 pm Hey all, This little devil is giving me a hard time. Weāve replaced the part twice already and the replacements wear out after a thousand hrs of operation or worse start chattering right away when we install them. Iāve isolated it down to the bearing as it seems to go away when I spray the hub with McLube but it comes back after a few minutes or as the RPMs go up. Does anyone have any thoughts or similar experience with this part?
6 RepliesMay 24, 2022 at 5:15 am Learn our web site–It shows what we have & don’t have.Last Post by:
posted: 1 year ago
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2007 QSC 8.3 do I have to remove raw water pump to change impeller?
This topic has 3 replies, has 4 voices, and was last updated by
1 year ago
May 2, 2022 at 10:23 am It appears the distance from the raw water pump to the electronic control panel is not far enough to get the impeller out of its housing. I have not yet replaced the impellers and want to. Just making sure before I get into it that I do not, or have to remove the raw water pump. Looks like poor engineering regardless. thanksĀ Ā
3 RepliesMay 22, 2022 at 9:58 pm Nope. You can get the impeller out without removing the pump or ecmĀ just did 2 thanksĀLast Post by:
posted: 1 year ago
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Voltage surge QSC 540ās
This topic has 5 replies, has 3 voices, and was last updated by
May 15, 2022 at 6:57 pm Volts sit constant around 13.2-13.7. I noticed while running at times the volts will spike in the 14-15 range then settle back to the 13.2-13.7 range. Sounds like something is cycling like a heater? Ā Happening on both engines at the same time while running.Ā <br /><br /> any idea on what could be cycling or cause if the spike in voltage? Thanks in advance.Ā <br /><br /> mike
5 RepliesMay 22, 2022 at 9:55 pm Alternator tested bad. Replaced and all good. Thanks.ĀLast Post by:
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Cummins overheat and prop question
This topic has 1 reply, has 2 voices, and was last updated by
May 22, 2022 at 7:01 pm Hello everyone we are looking at buying a new to us boat home, we’ve lived aboard 9!years and have decided to go to a trawler. It’s a 40′ full displacement tug style wit edeh a 6BTA5-9M2Ā 300hp. My question is I have a sneaking suspicion it was overheated . All of the injectors and fittings near them are rusty and reddish as of the paint was cooked off from high heat. Is this possibly normal on this version? 300 hp?Also the mec…
1 ReplyMay 22, 2022 at 9:43 pm Well the HX has not been serviced. That I can see. Ā Can you take more pics from further back so we can see the entire engine bay. Thanks.ĀLast Post by:
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6BTA Oil pan and fitting threads ID.
This topic has 4 replies, has 2 voices, and was last updated by
1 year ago May 20, 2022 at 9:55 am Hi, I just removed one rear fitting from one of my 6BTAs Oil pan, and would like to replace these as they are showing quite a bit or rust. To clarify, this is the 90 degree fitting that threads into the rear of the aluminum oil pan and can be used either for the oil change suction hose or for a crank case vent from the AirSeps (this was eliminated and will useĀ a SBMAR puke bottle system). Anyways this fitting has a straight thread with oring to…
4 RepliesMay 22, 2022 at 6:55 pm Cummins has been amazingly inconsistent over the years as to the “standards” as to “what threads for what” they choose.. Even the latest QSB 6.7 has some “crazy sizes” that make no sense..ĀLast Post by:
posted: 1 year ago
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Freshwater Flush Question for Tony
This topic has 8 replies, has 2 voices, and was last updated by
1 year ago May 5, 2022 at 6:22 am Thanks, Bill D
8 RepliesMay 20, 2022 at 6:19 pm UnderstoodLast Post by:
posted: 1 year ago
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What Aftercooler do I have ? MOTA or Serek Designs
This topic has 0 replies, has 1 voices, and was last updated by 1 year ago
May 20, 2022 at 5:12 pm Hopefully this will help the boating community as to sorting the new changes in aftercooler design Cummins has come up with.. It used to be easy for me as itĀ all set in my “memory bank”.. Corey put most of this together and Justin & I added some thoughts.Ā I am sure this will be a “moving topic” are these newer coolers get a few years of “Marine Age” on them. Now I even have to look at pictures and notes …
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4bta 250 thermostat???
This topic has 1 reply, has 2 voices, and was last updated by
1 year ago May 16, 2022 at 8:55 am Servicing the heat exchangers this coming fall/winter and was wondering if I should swap out the thermostats from the 180’s to the 160’s SKU:Ā TS-B160KIT…. Also will these fit in the 4bta 250hp diamond series?
1 ReplyMay 20, 2022 at 4:03 pm Fit is perfect————–4b-6b all the same.. Your call on the temp you want run at..Last Post by:
posted: 1 year ago
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Sudden black smoke and low rpm
This topic has 4 replies, has 2 voices, and was last updated by
1 year ago
May 17, 2022 at 12:02 pm Hi all, This weekend I went out with my Bertram 30 after three months in the dock. The boat has a pair of 1993 cummins 6BTA 5.9 engines with 1400 hours (well mantained). The boat started perfectly as always and after 10 minutes of ride I accelerated it but the starboard engine wouldn’t go above 1700 rpm and I noticed a significant amount of black smoke coming out of the exhaust. I continued the trip at low Rpm (no black smoke at low Rpms) …
4 RepliesMay 19, 2022 at 12:27 pm Noticed, many thanks!Last Post by:
posted: 1 year ago
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Cooler Cleaning
This topic has 2 replies, has 3 voices, and was last updated by
1 year ago May 5, 2022 at 8:10 am What is everyone using to clean after coolers and heat exchanger and are the leaving them in the housing or removing them Cummins QSC 8.3 What product are you using to clean? Remove them from the housing to clean? If removed is it ok to get cleaning product on air side of aftercooler?
2 RepliesMay 19, 2022 at 11:01 am All raw water coolers need servicing and should have their cores removed to be cleaned. ie; the heat exchanger and the aftercooler especially or you won’t be able to fully clean the airs side of the core. It’s best and easiest to remove them and perform the services on the bench.Ā Aftercooler: https://www.sbmar.com/articles/cummins-marine-aftercooler-maintenance/Last Post by:
posted: 1 year ago
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6bta aftercooler core fins???
This topic has 8 replies, has 3 voices, and was last updated by
1 year ago May 14, 2022 at 8:51 am Recently pulled the aftercoolers for cleaning off my twin 6bta 370ās for the first time since Iāve owned the boat. Ā Iāve owned it for around a year and the boat is a 2003. Ā Iām not sure if this is normal or not but thereās a gap between the casing and where the fins start – see pictures. Ā Is this typical, or is there a reason for this? Ā Both cores from port and starboard are the same. Ā
8 RepliesMay 18, 2022 at 8:02 pm The real question here is what your plan is..Ā You either fix the “why is happened” or you don’t.. It’s called a poorly designed exhaust system..Ā You are very lucky as you have plenty of room to fix the “why” .. Many boats/engine installs do not.Last Post by:
posted: 1 year ago
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Disconnect fuel cooler
This topic has 7 replies, has 3 voices, and was last updated by
1 year ago
May 12, 2022 at 6:39 am Hi TonyĀ I will try to take out my fuel cooler. I have watchedĀ your video clip on YouTube.Ā But my fuel manifold has to small Black hoses in the down corners.Ā My question is do they have anyĀ connection whit my tank?? Or do I have to puy the hoses together?Ā I hope my English is decent.Ā Regards Torgny.Ā
7 RepliesMay 18, 2022 at 12:36 pm RobĀ Thanks fore your info is very helpful. Regards Torgny.ĀLast Post by:
posted: 1 year ago
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1999 Diamond C Series Loud Rattle
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This topic has 37 replies, has 8 voices, and was last updated by
2 years ago March 4, 2022 at 3:58 pm Hello all, I have joined the forum to ask for help with an annoying problem with my starboard Cummins 450c motor. Last month when starting the boat up the starboard started rattling and at first we thought it was the belt so that was changed along with the tensioner. Once that was done there was a definite noise from an Alternator bearing so that was changed. Now, once those little noises were taken care of all that was left was a noisy rattle f…
May 17, 2022 at 6:38 pm It’s pretty obvious that what I am looking at went poo-poo long ago and was trying to tell someone listening “something”.
37 Replies
Last Post by:
posted: 2 years ago
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Fuel Filters Leaking
This topic has 7 replies, has 3 voices, and was last updated by
2 years ago May 8, 2022 at 5:03 am Hello, I have off engine multi stage fuel filtration (cummins filter heads) that leak a very small amount of fuel when the boat sits.Ā I am using fleetguard FS1000’s and a bulk water separator inline. The filters (4) weep a very small amount of fuel past the gasket, maybe an ounce or less when the boat sits after use. I have checked the mating surfaces which are clean and smooth, there are no old gaskets stuck to the filter heads, and I ha…
7 RepliesMay 16, 2022 at 6:13 am Tank Vent Issue??—————Get it all 100% clean and dry. Remove the fuel fill cap do a few daysĀ ( just cover it).. Then check for any new leaks. If pressure in the tank ( under 5 PSI) from heat changes is causing this leak,Ā you are missing something in the head designLast Post by:
posted: 2 years ago
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6B Coolant Plumbing and Flow Questions
This topic has 3 replies, has 2 voices, and was last updated by
2 years ago May 14, 2022 at 8:42 am Hello, I am in the planning stage of installing new SMX Coolant Temperature Alarms on my 370B twins (CPL2208). I have read thru all of Tony’s tips and also my O&M manual, but need a few clarifications as I plumb in my new hi-temp coolant switches. My Port side is no problem – My Stbd side with existing hot water heater plumbing is a bit more challenging. I read thru the excellent Redundant Alarms article. My questions relate to t…
3 RepliesMay 15, 2022 at 6:28 am Yes,Ā the BYPASSĀ you are searching for is controlled internally thruĀ the thermostat housing & thermostat design on all B engines. This design came out it in the late 70’s and very early 80’s when the “B” series engine came off the drawing board and was put into production as an industrial engine and has really not changed since. Must be pushing 10++ millions engine later?Last Post by:
posted: 2 years ago
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Rotella T4 to Mobil Delvac
This topic has 4 replies, has 3 voices, and was last updated by
2 years ago May 11, 2022 at 5:02 am 6bta Normally run Rotella T4 15w-40 Locally could only find Mobile Delvac 15w-40 I assume no issue running the Mobile, but aĀ friend gave me a hard time so just thought I’d ask the group if anyone is superstitious about jumping between brands? ThanksĀ
4 RepliesMay 13, 2022 at 4:47 am The only think to be mindful of when changing brands is that it could change an oil sample report but a sampling of unused oil can clarify any confusion there..Last Post by:
posted: 2 years ago
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Fuel coming out of the exhaust 6BTA 5.9 -M
This topic has 7 replies, has 2 voices, and was last updated by
2 years ago May 6, 2022 at 8:18 am Hello to all , I have had a serious leak of diesel fuel coming out of the exhaust of my 2002 5.9 of course I quickly ordered a new set of injectors which have not arrived yet. But yesterday in the back of the boat itās was smelling diesel and I saw a small amount of diesel fuel on the water behind the boat. I went and closed all the fuel valve on the boat which stop the leak but it got me thinking itās not the injectors but maybe this diesel fue…
7 RepliesMay 12, 2022 at 5:54 pm Glad the fuel coming outĀ the exhaust outlet went away–You got lucky that the internal pressures in the return line system were high enough that it keep the fuel tank from filling with seawater.Ā The flow of any liquid will always follow the easiest path to zero pressure.ĀLast Post by:
posted: 2 years ago
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qsc 8.3l soot were exhaust exits turbo
This topic has 2 replies, has 3 voices, and was last updated by
2 years ago
May 9, 2022 at 3:19 pm there is soot were the exhaust leaves the turbo at the elbow not the was gate. it looks like it is coming from the mating surface of the elbow to turbo the 4 bolts are tight i cant even get them to loosen i afraid they will brake been soaking them for days. is there a gasket there? thanks for any inputĀ
2 RepliesMay 10, 2022 at 12:06 am I’ve had exactly the same. Also suspected the wastegate shaft, but it wasn’t. In the end it appeared to be a tiny hair crack in the ss exhaust riser just on the flange where it connects to the turbo. Had that welded and all good. Yes there is a metal gasket between riser and turbo.Ā Lots of luck, AndrĆ©Last Post by:
posted: 2 years ago
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Bleed screw adaptor QSB 5.9
This topic has 1 reply, has 2 voices, and was last updated by
2 years ago May 9, 2022 at 10:10 am Hi I would like to use / make up an adaptor to use when i bleed the fuel system on my QSB 5.9 I would combine and use the system you suggest using the squeeze bulb priming method but would like to screw in an adaptor to the fuel filter head to capture the expelled fuel into a suitable receptacle rather that spill diesel so my question is what is the thread size on the bleed nipple ? Is this something that you have covered previously ? the filter…
1 ReplyMay 9, 2022 at 5:06 pm 10 x 1.0 mmĀLast Post by:
posted: 2 years ago
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Engine loading
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