Unresolved problems with Cummins QSB 6.7 liter engine

The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.
See posts with no answers
Theoretically it was intended to rule out contamination of the fuel tanks as a source of the problem, which Cummins is trying to suggest. On the QSB6.7, there is a lift pump and a high pressure pump. One suggestion is a faulty check valve in the lift pump. This might cause the fuel to back flow and lose prime. That might cause the shutdown immediately after starting issue. That wouldn’t account for the loss of rail pressure under load since the lift pump shuts off after the engine is primed. That could be due to a failure of the high pressure pump or a faulty fuel pressure relief valve. I don’t know much about diesel engines but I’m getting a painful education.
 
Have you spoken directly with Cummins? I expect they must have some sort of customer care number you can call in order to escalate the problem.


I know it's no help or consolation to you, but might help others building new boats.... Any notion that a new cruising boat is a step-in-and-drive-away affair is a complete fallacy. The idea of a trouble-free new car does not in any way translate or carry over to a new boat. If anything, new boats take LONGER to get sorted, not less time vs a brokerage boat. In my experience, any new cruising boat will take up to a year to get sorted and working properly. And you can pretty well count on one or more weird-ass problems like this. It sucks, and I completely feel for you, having gone through it myself a couple of times. But it's the reality of one-at-a-time, handmade boats, and expectations should be aligned accordingly to minimize frustration.
 
twistedtree said:
Have you spoken directly with Cummins? I expect they must have some sort of customer care number you can call in order to escalate the problem.
Click to expand...

Thanks for the input. At this point our only contact with Cummins has been aboard the boat with their field technician. Helmsman Trawlers has been communicating directly with Cummins above the technician level. We are reluctant to interject ourselves into that discussion. We really didn’t expect a trouble-free boat but we didn’t think it would take four months to fix a problem discovered upon delivery. It took two months just to get a tech on board.

If anyone knows a contact at Cummins or an avenue for getting action taken, I would like that information. I have posted on the Seaboard Marine website forum and got an immediate response from owner Tony Athens, who is the go to guy for Cummins issues. He incidentally owns a QSB 6.7 engine. I have given him engine photos he requested and a copy of the tech’s last field report.
 
twistedtree:
I take your comment on a new boat build and sorting out glitches very seriously, especially that I'll be taking delivery of hull#1 of the H46 series. Having owned a well built new 38E recently is one reason why I chose to have the first H46, and Helmsman has given me all the assurances they can on the build quality, fit and finish. However, it will be hand-built, the first of the line, and I believe, as you put it: 'expectations should be aligned accordingly to minimize frustration."
Robert
 
BTW, I don't mean to diminish Doug's issues, or in any way defend the slow progress is fixing it, or suggest that such problems are OK. They are not OK. Just keep on them to get it fixed, and know that eventually it will get fixed and you will have a wonderful and reliable boat.
 
Last edited:
No problem continuing to go through Helmsman, but I would start asking about the escalation process, and ask to be included in phone calls with Cummins. Cummins needs to know you are upset. Quiz them on next steps, when, and by whom. Their best and brightest should be on this by now. This is a "disabled boat" situation, and should be a top priority. All the big manufacturers have ways to hustle when a problem has taken a machine out of service.


Perhaps ask Tony about the escalation process? And perhaps tell Helmsman that you are going to be hiring Tony and sending them the bill since they have been unable to rally forces to resolve this. Don't be a dick, but be insistent that much more is needed on solving this, and that the timeline has been unsatisfactory. If they can't get it fixed, you will and will send them the bill. Also make sure Helmsman knows this is getting a lot of air time. They have gotten great favorable coverage here on TF, but the good gets coverage along with the bad, so get on it. People will just remember how the problem was resolved, not what the problem was.
Oh, and perhaps have a private conversation with DHayes. He had an engine issue and Cummins stepped up and replaced the engine, lock stock and barrel. He may know the escalation process, key people to talk to, etc.
 
It seems this thread is going around the same ever repeating issues. Sure talk to Seaboard, Cummins, Helmsman and Mr Hayes. When is time up on being nice?
 
twistedtree said:
Oh, and perhaps have a private conversation with DHayes. He had an engine issue and Cummins stepped up and replaced the engine, lock stock and barrel. He may know the escalation process, key people to talk to, etc.
Click to expand...

I can’t find that username on TF. Is there another way to get in touch with Dennis Hayes?
 
His handle is dhays. He’s got a NP43 in Gig Harbor WA
 
I'll second TT's take on a new boat. On a new custom boat you have to figure a year, maybe two to get everything sorted. On a production boat you'd hope for less, but it can still be awhile. These are built in small enough quantity that they are essentially prototypes, in mass production terms.

Cummins and others seem to say the lift pump shuts down after the engine starts. Again the QSB5.9 and 6.7 may be different - but on the 5.9 the engine will falter and stop if the lift pump stops long after (hours) the start. So I am skeptical of that intel. The high pressure pump moves a LOT of fuel in these engines, especially at max rpm. On the 5.9 the spec is something like 50 gallons/hr including the spill fuel. The lift pump looks very similar to an automobile injection pump, it isn't going to be easy to suck 50 g/hr through one that isn't running. I've got a bad one I think I will cut apart when I get home.
 
1-2 years to get a 6.7 running right? I don’t think so provided Helmsman and or Cummins are appropriately engaged.

The OP and Cummins point to a fuel delivery problem. A Cummins tech should be able to pin this down pretty quickly whether fuel flow to and from tanks or directly related to engine. Having spent the past few days with a top attorney and generally mentioning this conundrum there are failure to perform issues at play here.
 
It’s not often I have a different take on things than TT but possibly do here.

I had a semi custom boat built for me. As TT says took a year to sort out to a degree I felt totally comfortable doing passage with her. But it was small stuff. Usually calibrations were off or a supplying vendor screwed up and a part needed to be respec’d and replaced. The company was owned by a single individual. I had his cellphone number. He was incredibly responsive and everything done on his dime. He was the interface to supplying vendors. Work done promptly. (He has since sold the company unfortunately).

I never was unable to use the boat but it did take a year for me to have true confidence in her which did change how she was used. You are in a situation where I would be reluctant to use the boat. Loss of propulsion is a big deal.

I can’t think this thread is making the readers feel warm and fuzzy about buying your brand of boat. I would go to the principals of the company directly. The owners of it not the managers or intermediaries and tell them the story as well as refer them to this thread. They have the wherewithal to get Cummins to be responsive as well as the folks inside their company. They have the most skin in the game beyond you. This thread is the worst type of negative advertising for their company. Owners of Helmsman want this thread to stop as soon as possible by having a satisfactory resolution. They are your biggest ally. Use them. Way it stands now I’d be very reluctant to have Helmsman build a boat for me. I think other readers of this thread feel the same way. Owners know this so will help you rapidly to your complete satisfaction.
 
Last edited:
Doug,
+1 to what Hippo stated.
Also, I followed your post on Tony's site (sbmar.com), and advise you give him all of the info and photos he requests. He is very knowledgeable and experienced with Cummins, and will most likely be able to provide good suggestions on how to go about determining what is going on with your engine. He is a no nonsense kind of guy with years of field experience, and is not a "paper smart", but is a "real world" smart kind of guy.

Ensure that whoever does further investigation into your engine, either follows Tony's suggestions (copied from his post):


"Did the “tech” perform the most obvious tests based on the symptoms??

Put a 0-100 PSI analog gauge on the on-engine last chance fuel filter to “see” if you were having fuel supply issues? I believe pressures there are in the 80-90 PSI range when running on a 6.7

Did he 100% assure the that the one-way fuel check valve next to the electric fuel pump down by the ECM was not installed backwards– We have now seen two of these with symptoms very similar to yours. Pics of this on this web site.
https://www.sbmar.com/articles/qsb-6-7-fuel-hook-ups-and-fuel-direction/

Did he put a analog vacuum gauge between the engine and the fuel tank and monitor it while running?

Did he cut open the on-engine fuel filter and dump it into a clean glass container to “see” what is getting to it ( past your off-engine primany filters system?

ECM alarms / codes are great but do not always pin-point issues like you are describing ?"


or have the Tech explain the reasons why (in layman's terms so you can fully understand and/or relay to Tony) that test is not needed or useful.

Scott at Helmsman should be able to apply pressure on Cummins to get this issue resolved quickly, and it is in both his and Cummins best interest to do so.
Good Luck.
 
Just had same problem that became more and more frequent.

Occurred on port engine in 3' beam sea. A sharp slap wave.

Ended up being starter relay base. That relay controls voltage to the engine circuit and I assume fuel solenoid.

In this case base was bad, not sure why, but once changed out no problems.bof course after fuel filters and with no test meter.

Always change relay base to one with mechanical bale to hold relay tight. Then use a relay with a mechanical latching test circuit.

So now you can hold relay closed to test circuit.

In this case relay was on port side of engine, should have been mounted in a better place.
 
firehoser75 said:
Doug,

Did he 100% assure the that the one-way fuel check valve next to the electric fuel pump down by the ECM was not installed backwards– We have now seen two of these with symptoms very similar to yours. Pics of this on this web site.
https://www.sbmar.com/articles/qsb-6-7-fuel-hook-ups-and-fuel-direction/
Click to expand...

That is interesting. The 6.7 lift pump looks identical to the 5.9, except for the addition of the bypass with check valve. I assume the lift pump is used to prime the high pressure pump and then shuts off, fuel then uses the bypass. Seems like if the check was installed backwards the engine would shut off as soon as the lift pump stopped. It also opens the possibility of hot wiring the lift pump on to see if it solved the problem. If so, somewhere the high pressure pump is loosing prime (air leak upstream between it and the tank).

The suggestion of pressure gages on the fuel system are good ones.
 
Doug, I was thinking about this some more today and you might want to research WA consumer protection laws, and vehicle lemon laws. Applicability to boats would be a first question, but these often set limits on number of repair attempts, and number of days out of service before the manufacturer is requires to replace or buy back the product. These might provide some added leverage. Warranties typically exclude loss of use and any consequential damages, but state laws will over-ride that if they exist.
 
twistedtree said:
Doug, I was thinking about this some more today and you might want to research WA consumer protection laws, and vehicle lemon laws. Applicability to boats would be a first question, but these often set limits on number of repair attempts, and number of days out of service before the manufacturer is requires to replace or buy back the product. These might provide some added leverage. Warranties typically exclude loss of use and any consequential damages, but state laws will over-ride that if they exist.
Click to expand...

I'm going to do some looking into that as I currently have nothing else to do. Helmsman Trawlers did performance tests on the boat Friday and today and repeatedly asked Cummins if we could operate the boat without damaging the engine. Cummins has not responded and we are about to cancel a long-planned outing with family visiting from Oregon. I think we have reached the point where our damages come into play and our next advice will be legal rather than technical.
 
Doug
Quite simply, the vessel is currently not safe to operate.. A prudent owner would not put his vessel and occupants at risk with the already proven shut downs occurring.

An unanswered question, is Helmsman willing to pay for Seaboards time and travel to get this sorted out. Cummins ineptitude has been established thus an expert and independent assessment is required.
 
As someone awaiting delivery on a new H38 sedan, this thread is very unsettling. Please continue updating as to progress and decisions about legal avenues available. My only other note is that Tony Athens is a terrific resource and great to work with. He's helped us out several times over the years with previous boats.
 
I would be talking directly to the owner of Helmsman and corporate at Cummins. At this point it can’t hurt. I would let them know that they are getting a lot of bad press. Also talk to the Attorney General in Washington and see what resources they can bring to the table. Talking to a tech at Cummins doesn’t get them to put any priority on your problem.
 
Things are getting interesting. After three unsuccessful visits by the same tech, we have gotten a little more aggressive in our approach. We have contacted Tony Athens, the Cummins guru everyone says we should be talking to. We forwarded his observations and recommendations to Scott and Van and let them know we were going to a Cummins service manager that another Helmsman owner said we should be talking to. Scott contacted Aaron Pierce, the Marine Services Manager for the western U.S.

My son and his girlfriend arrived yesterday for a planned outing of several days on the boat leaving today. We had asked Cummins if it was safe to operate the boat. No one at Cummins would give us an answer until this morning when we heard from Aaron Pierce. He said we should not operate the boat because he suspects a bad lift pump has introduced metal shavings into the high pressure pump. He has lit a fire under Cummins in Everett. The tech will be here tomorrow at 6:00 AM to replace the lift pump, high pressure pump and fuel filter. He and Van will take it on a sea trial tomorrow.

I learned from Van today that they requested a service call on March 23, three days after our near disaster at Shilshole. Cummins did not schedule a tech visit until April 28 and postponed it until May 8th. I think Scott and Van are making a real effort to make things right. Cummins has dropped the ball. If you have engine problems, demand to be kept in the loop. Don’t let them sequentially try one fix after another until something works. Make them prove it has been fixed.
 
Good for you. You can’t just sit back and wait. You have to take an active role in the process. I had a problem with Cummins and I found the area manager and got the problem resolved in a day. Good luck!
 
I am sorry to hear about the issues, just bad all the way around. I know Shilshole and there is know way I'd want to be around that breakwater with a sketchy engine. Depending on wind and tide you could easily be in trouble in less than 60 seconds with a dead engine.

If the theory is that metal shavings made it to the high pressure pump, are they testing for any damage the shavings may have made past the high pressure pump? I don't know this engine but I am assuming the filter is before the pumps. Again not knowing the engine but it seems like the injector spray patterns and flow rates may need to be validated. Armchair mechanic here so take my comments with a grain of salt.
 
The proper nature of escalation involves moving up the chain a level at a time, giving each their shot to make things right.

You can’t just begin with the nuclear option treating HQ staff like ground level service techs.

Sadly, this takes time. But necessary.

When Cummins replaces the whole fuel system and it works we may not know the ultimate cause, so please share any postmortem you may get.

Congratulations on the resolution about to happen.
 
The good news is you had the pull of Helmsman on your side. Pretty unlikely you would be getting HQ attention on your own for a used boat.
 
Thanks for the update Doug. Let us know how the tech visit goes today.
 
You must log in or register to reply here.

Similar threads

dhays
High GPH at normal rpm or low rpm at normal fuel consumption
Replies
27
Views
1K
rgano
rgano
Waterant
Cure for Yanmar diesel engine smoke?
Replies
12
Views
2K
Dougcole
Dougcole
SeaDogAK
RPM drop
Replies
12
Views
2K
twistedtree
twistedtree
T
Onan MDKAF dies when start button is released
Replies
28
Views
2K
C lectric
C lectric
Spike
DD 6-71 ti air in fuel system
Replies
4
Views
689
Spike
Spike

Latest posts

Back
Top Bottom