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- Cummins Marine Forum Topics
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Understanding The Reprop Curve for QSM 11-715
This topic has 1 reply, has 2 voices, and was last updated by
1 year ago March 15, 2023 at 2:17 pm All Looking for a solid answer. Have been reading everything I can to understand that if your QSM is Re-propped according to the recommendation then should you or should you not be able to run at WOT or is it always a cruise below 18.6 GPH at 2000 RPM? Going off this comment from another post: “…it is far from OK if you want to help prevent early exhaust manifold leaks or worse… The damage to the turbo’s and manifolds do not happen…
1 ReplyMarch 15, 2023 at 5:26 pm IMO, WOT is for very occasional testing of base line performance for a few seconds max.. The QSM11 engine is a rock solid engine platform, but the dry manifold/turbo system does not do it justice. The same engine with a coolant cooled turbo & Manifold can run 1000 of hours a year burning 20 GPH at 1850 RPM and will give no grief. Limit, by proper propping , the GPH at 2000 RPM to 18-19 GPH and you’ll may get some decent life from…Last Post by:
posted: 1 year ago
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Onan Generator fuel leak
This topic has 1 reply, has 2 voices, and was last updated by
1 year ago March 13, 2023 at 11:30 am I have an Onan 17MDKBP generator that has developed a small fuel leak. I’m trying to determine what needs to be replaced or repaired. I have traced it to the valve in the photo – you can see a ring of diesel around the shaft. The valve operates – when you turn it, fuel comes out of the opening – but when it’s closed, fuel slowly drips out. I’ve looked through the diagrams and parts manual, but do not see this…
1 ReplyMarch 14, 2023 at 3:04 pm That looks like the coolant drain cock to me. P/N 185-5846Last Post by:
posted: 1 year ago
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6CTA 8.3 M3 450 max rpm 2400
This topic has 3 replies, has 2 voices, and was last updated by
1 year ago March 9, 2023 at 8:32 am 2001 52 Offshore with 6cta 8.3 m3 450. 31 x 31 3 blade factory installed props. During the sea trial we could only get 2400 rpm out of each engine? Any suggestions as to why.
3 RepliesMarch 13, 2023 at 9:12 am CW, It dawned on me that I should state that we do realize that the Offshore 52 is a boat that you would mostly run at hull speed or less but has the ability to be run faster if need be. I have looked at a couple Fleming55’s with Diamond 450’s. The ultimate goal, if you acquire, should be to go though the entire drive train and make sure that everything is in good working order and then dial in the propellers so that you are able t…Last Post by:
posted: 1 year ago
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Coolant Loss Troubleshooting
This topic has 2 replies, has 2 voices, and was last updated by
1 year ago
March 10, 2023 at 12:21 pm Background: Port engine currently has 959 hours on it. Approximately, 173 hour ago @ 780 hrs (1.5 seasons) my port exhaust manifold failed causing an overheat condition. (never got an alarm but the code was there). The end result was having to have the head milled 17/1000ths (it was during covid and replacements parts were not available) and replacement of the heat exchanger (used part with similar hours…best available at the time). Sinc…
2 RepliesMarch 11, 2023 at 3:06 pm They are QSB 5.9 425HP Really hard to get a good picture while in the boat but hopefully these get you want you need.Last Post by:
posted: 1 year ago
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Cummins 6bt wont get up to WOT after fuel line blockage
This topic has 9 replies, has 5 voices, and was last updated by
1 year ago March 3, 2023 at 8:13 pm Hi All i just got the motor (Cummins 6bt 250hp) running after a fuel blockage (massive build up of gunk in the fuel line and the primary fuel filters). I primed the system and got fuel going through, cracked the injectors and waited for the bubbles to stop. just took it out for a quick run to see how it was going and it runs smoothly and is smoking a lot less than it was! But won’t rev past 2200 RPM Any ideas?
9 RepliesMarch 11, 2023 at 12:41 pm Leave the fuel fill caps off when introducing air pressure into the fuel lines. You should remove the fuel pickups and check the tubes for clogged screens, etc. Any screens on fuel pickups are bad, you want the pickups to act like vacuums and allow the filtration system to get the junk and filter it out. Therefore, pickups should be large diameter and very close to the bottom of the tank.Last Post by:
posted: 1 year ago
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Vibration
This topic has 2 replies, has 2 voices, and was last updated by
1 year ago
March 9, 2023 at 4:09 pm I have a 2006 450C 5000 hours engine runs great is burns no oil and no smoke. It runs good and has be maintained. It has a bad vibration or shake like something is out of balance at 1000rpms we can´t pin it down. Its bad under load it does it in neutral but not bad. It has a new Cummins injectors not rebuilt, new torsional damper plate, new motor mounts, New shaft aligned correct. Everything is in order. Above or below those rpm´s it runs fine…
2 RepliesMarch 11, 2023 at 9:40 am Tony I won’t be back in the boat for 10 days. I am being told its a problem with the centa damper its exactly at 1000rpm The engine has always had a shake at 1000rpm.Last Post by:
posted: 1 year ago
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Cummins QSB Low Battery ECM Voltage
This topic has 5 replies, has 3 voices, and was last updated by
1 year ago
March 2, 2023 at 9:46 am Pair 425 QSB’s with SC V1 and a VV4 display. I had an electrical problem in the boat hangar and I lost power while I was out of the country and the batteries died. I have charged everything up and the batteries are fine and hold their charge and I don’t see any issues but I have a persistent low ECM voltage alarm on both engines which are on separate batteries. I see full voltage on both batteries and have run the boat for 6 ho…
5 RepliesMarch 9, 2023 at 8:00 am I just redid those wires to connect them directly to their starting batteries after having problems with them connected to the main DC panel. The terminals are clean and show full voltage at the battery and at the terminals on the ECM with my Fluke meter. I am wondering if even the batteries showing full vooltage they were damaged when they discharged.Last Post by:
posted: 1 year ago
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6CTA 8.3-M3
This topic has 8 replies, has 6 voices, and was last updated by
1 year ago February 2, 2023 at 6:43 pm In Arizona and temps may be a bit colder than I I remember last winter. Noticed both of my 6CTAs running a little rougher than usual and more white smoke than usual for longer. My boat mechanic noticed that my grid heaters weren’t hot to the touch. I later noticed that each motor had a free floating wire I’m assuming are ground wires. I purchased the boat in Los Angeles in 2021. I’ve seen on other forums that people in warmer climates run their …
8 RepliesMarch 9, 2023 at 6:07 am Learn “Tonys Tips” It all there How to Deal with the Cummins Marine Air Heater CircuitLast Post by:
posted: 1 year ago
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On my Riv boat with 2 Cummins 6 BT Engines fitted engine hours readout has fade
This topic has 2 replies, has 2 voices, and was last updated by
1 year ago
March 7, 2023 at 2:17 am On my riviera boat with Cummins BT engines fitted the digital readout for the engine hours has faded out for both engines , ant ideas how to get these back thanks Dave
2 RepliesMarch 7, 2023 at 11:36 pm Hi Tony thanks the engines are Cummings B 370 bta 5.9 im not sure how to send you photos although I think I have one below it’s showing theengine hours are faded out this is on both gauges I’m just wondering what the problem is and how to fix it tthanks DaveLast Post by:
posted: 1 year ago
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Seawater In Coolant
This topic has 1 reply, has 2 voices, and was last updated by
1 year ago March 7, 2023 at 1:15 pm I am running a 35 Bertram with a pair of 330 6bta’s. <br /><br /> On the way home from our last charter I noticed the port engine running cooler thank normal. They normally run 185, and it was down about 178. <br /><br /> I went down and checked the engine room, and noticed salt deposits around the lid of the coolant tank on the engine. Saltwater was leaking out around the lid. When we got home we tested it and sure enoug…
1 ReplyMarch 7, 2023 at 7:09 pm Most likely an Internal HX tube failure–Pull it and have it pressure tested at a local radiator shopLast Post by:
posted: 1 year ago
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ZF 63A with 4BT, flywheel torsion coupler issue???
This topic has 2 replies, has 2 voices, and was last updated by
1 year ago March 1, 2023 at 8:54 pm Hello Everyone, The boat has had smoke come from the bell housing, and smell like burnt rubber twice over the last year. The first time was on the sea trial. We ran the engine up to 2700-2800 rpm’s , the engine began to vibrate , smoke came from the bell housing and had the smell of burnt rubber. We brought the throttle back down and it stopped. Then this July I was running back on a trip and decided to bring the engine up to 2300rpms. Once agai…
2 RepliesMarch 5, 2023 at 7:31 pm Thank you for the advice Tony.Last Post by:
posted: 1 year ago
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Oil Analysis Results on 480CE
This topic has 5 replies, has 4 voices, and was last updated by
1 year ago
February 24, 2023 at 1:18 pm Hello all, I have been browsing this forum and am very impressed with all of the information and guidance it has provided. I put in an offer on a 2003 Tiara 3800 with Cummins 6CTA 8.3 480CE engines and it was accepted contingent on Oil Analysis and Sea Trial. Unfortunately never made it to sea trial as the oil analysis came back with 150 PPM Iron in the starboard engine (port is only at 5 PPM Iron as reference since I know oil analysis is used…
5 RepliesMarch 2, 2023 at 8:58 am FWIW, on my 390 MY, dropped an exhaust valve seat. Took 90 hours to do the rebuild, 28 to swap the head on the other side. All was done in the boat and did not tear up the salon to remove the engine covers. The bill for the rebuild was 22K, the head swap on the other side around 10K.Last Post by:
posted: 1 year ago
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6BT 210 cranks but won’t fire.
This topic has 4 replies, has 4 voices, and was last updated by
1 year ago
February 20, 2023 at 7:18 pm I have a 12 month old 6BT 210 Cummins factory reman engine that cranks but will not fire. I was anchoring, clicked the starboard engine out of gear then back into gear to nudge forward and the starboard engine stalled. I managed to restart it but it cranked over for about 15 seconds before it fired (until that day if fired immediately, 1-2 seconds). Next morning I started the engine to leave and it cranked for about 8 seconds and then ̶…
4 RepliesMarch 1, 2023 at 11:09 pm Fully open the throttle when cranking, just remember to pull it back quick when it starts.Last Post by:
posted: 1 year ago
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Cummins 6bta 5.9 260 hp will not stay running.
This topic has 2 replies, has 3 voices, and was last updated by
1 year ago
February 24, 2023 at 8:56 am I removed the bridge from my 34 Crusader with twin 6BTAs along with all bridge controls. Engines start and run for around 1 to 2 seconds and then shut off (I assumed the secondary fuel solenoid not getting 12 volts). I checked and cleaned all grounds and wires – no luck. I then plugged the gauge panels from the bridge back into the system (where they split from the wiring under the dash) and the engines ran perfectly. My question is whethe…
2 RepliesFebruary 28, 2023 at 11:29 am Have you used a voltmeter, DMM, to check for proper voltage to activate the fuel shutoff solenoid. It sounds like the engine does start and then quits. When exactly does it quit? Get, make some long leads with good clips that will stay on the solenoid terminals so you bring the meter out to where you can watch it while starting the engine . Watch the voltage when you try to start the engine. It should rise and stay there untill YOU …Last Post by:
posted: 1 year ago
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QSM-11 EGT installation questions
This topic has 14 replies, has 4 voices, and was last updated by
1 year ago
February 19, 2023 at 10:36 am So I just purchased the Tiara 4700 with QSM-11 715hp engines that I recently surveyed. I want to install EGT gauges before I run the boat and I was wondering if the Smart Craft 1.0 could display the temps without having to install a separate EGT gauge for each engine? I was also wondering where the thermocouple probe and fitting installs into the exhaust system? I’ve searched around but couldn’t find any info on the above. Thanks
14 RepliesFebruary 28, 2023 at 10:33 am Yes, the twin engine option has one gauge that displays the temps for both enginesLast Post by:
posted: 1 year ago
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6BTA 5.9 370 difference 6BTA 5.9 330
This topic has 3 replies, has 3 voices, and was last updated by
1 year ago February 27, 2023 at 9:38 am My 2002 40′ boat has twin 5.9 6BTA 330 engines. What is the difference between the 330 and the 370? What needs to be updated to convert from 330 to 370?
3 RepliesFebruary 28, 2023 at 8:39 am We also have a 40ft 2002 boat (Carver 396 with twin Diamond 370s) and live in Florida so I’ll give you my 2 cents…. 😁 Short answer – no, you will not NEED the extra speed. Long answer – My wife and I live aboard and rarely travel over 8mph (7ish knots) – unless the current is in or favor! 🤣 And since it is our home, we try to minimize any unnecessary transient turbulence – including going fast which is much …Last Post by:
posted: 1 year ago
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Biodiesel
This topic has 2 replies, has 3 voices, and was last updated by
1 year ago January 29, 2023 at 9:15 pm On the Island of Hawaii there is a 65 ft charter boat with Cummins Diesels running on Biodiesel. The owner is Fairwinds Cruises. The engines are derated from 450 hp to 350. I was on the boat for a day and there was no diesel smell whatsoever. I think the Engines are 8.3s . This info is all from the Commercial Captain and affirmed later by the owners representative. Since my Wife was so impressed I started thinking about this for my 8.3s. My info…
2 RepliesFebruary 27, 2023 at 6:40 am It sounds like you are referring to WVO (waste vegetable oil) or a combination of BIO diesel and WVO. “Usually” BIO Diesel is a mixture of BIO and regular diesel and gets referred to as BIO and the % of the mix (B5 B10 etc…) and is used normally for any diesel engine. When using WVO the “waste vegetable oil” needs to be at operating temperature and to accomplish this they run some kind of heater (like a heat exchang…Last Post by:
posted: 1 year ago
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QSM-11 715hp aftercooler service
This topic has 2 replies, has 2 voices, and was last updated by
February 26, 2023 at 5:22 pm So I closed on the Tiara 4700 Sovran this past week. Im in the process of figuring out engine work. So far I’m planning oil and filter service and replace one of the raw water pumps that has a small leak. Regarding propping, I plan to install EGT gauges and then run the boat again to see what the temps are at cruise and GPH. On the survey the numbers showed that I am overpropped but before I cut pitch down on the propellers I want to run the…
2 RepliesFebruary 26, 2023 at 8:42 pm Hi Tony, I just closed on the boat last week so haven’t done anything to the boat yet. I’m looking at what I need to fo to the boat since taking ownership. So are you saying that I don’t need to service the aftercoolers now and if I install and flush each time I run the boat I can forget about aftercooler service or significantly extend the time between services? My biggest question is whether I have to service them now as they’ve only b…Last Post by:
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6 CTA 8.3 M3 transmission out what other maint/prev?
This topic has 1 reply, has 2 voices, and was last updated by
1 year ago February 16, 2023 at 10:54 am Replacing the TwinDisc, already replaced the engine mounts and shaft seal; prop and shaft sent out and tuned. New cutlass bearing What about the engine rear seal? Engine is 25 years old with low hours. Just thought it would be good to do any preventative or periodic work there with the transmission in the way.
1 ReplyFebruary 26, 2023 at 6:52 pm If not leaking, what would do want to take that on? Not and easy job.Last Post by:
posted: 1 year ago
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Cummins 480 CE
This topic has 11 replies, has 6 voices, and was last updated by
1 year ago
December 23, 2022 at 9:26 am Hello, I am thankful I found this site. as I am looking at the 390 Sea Ray Motor Yachts to do some cruising and the loop . Most for sale have the 480 CE motor 800-1500 hours . From reading older posts : *It looks I should plan on new heads and Prop work at minimum ? *I should figure $15k – $20k ? *Are heads available? It seems like the smart thing is to go to a newer model but there are so many with the 480 CE at a good price (…
11 RepliesFebruary 25, 2023 at 2:15 pm Steve, I am running 23×25 props and love them with the 480CE. 2″ of pitch out and she purrs. I stick / hover around 22-2250 and sometimes at fast speed I’ll push her to 2300. If anything, i’m a little under propped but I’ll live with that 🙂Last Post by:
posted: 1 year ago
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Understanding The Reprop Curve for QSM 11-715
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