Official Cummins QSM11 Thread

SeaNile

SeaNile

Well-Known Member
Aug 16, 2010
1,522
Chadds Ford, PA
Boat Info
2003 50 Sundancer
Engines
Cummins QSM11
SeaNile,
Now what are you looking at ? Last I knew you were comparing the 480ce to the qsc500. 48 DB ?
 
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Mark.60 said:
SeaNile,
Now what are you looking at ? Last I knew you were comparing the 480ce to the qsc500. 48 DB ?
Click to expand...

03 50DA with QSM11s. Just need the weather to break so the boat can go in and we can schedule the surveys.
 
Seems that the exhaust manifold is on back order. Does anyone know where one can be found? Guess the other option is to send the manifold to a machine shop and hope to buy just the gasket and longer bolts?

What about the turbo. Is that back ordered as well?
 
I have a 06 44DB that is 300 miles from Pittsburg (ohio river). kept under a roof its entire life.
QSC 500's. Very well taken care of.
 
RBB said:
I have a 06 44DB that is 300 miles from Pittsburg (ohio river). kept under a roof its entire life.
QSC 500's. Very well taken care of.
Click to expand...

I'm still hoping that one of the two boats i am looking at works out. The 50 with QSM11s has been surveyed and sea trialed and we are waiting for the owner to return from vacation to see what his reaction is to the $31k in repairs/maintenance the engines need. Also waiting to hear back from broker #2 regarding a 52 DA and real world price to sell. He has a feeling the owners are going to be stubborn and hold onto their sky high asking price, on a boat that's been for sale for 8 months and received one low ball offer.

The 42/44 DB is what we wanted originally so if either of these boats fall through we will on the hunt for a 42/44 DB. Ideally with bridge AC and hydraulic swim platform.
 
I have a customer that installed one of my wireless remote helms on his 48MY which has the QSM 11 engines. He installed the system at the time he purchased the boat. He has had an intermittent problem on his starboard engine that so far no one has been able to trouble shoot. Some times when he selects either forward or reverse the engine will drop 200 RPM for a few seconds, then recover. He has had it happen in cruise at 1900 rpm but mostly it happens at idle when going in and out of gear. He contacted me to see if I thought it could have anything to do with my wireless helm control. Apparently some one suggested that the neutral safety switch or circuit could be the issue but I fail to see how really anything with the drive solenoids would cause a 200 rpm drop. I would suspect the electronic fuel control first. He has had a Cummins tech out to the boat but of course since this happens intermittently the problem could not be reproduced while the tech was there. Since he installed the system when he bought the boat he has no idea if the problem was pre-existing so he is going to disconnect the wireless helm for a time and see if the problem persists. Anyone here think that a drive solenoid or neutral safety switch wiring could cause this? I have the system on three other QSM 11 powered Sea Rays with no reported faults.
 
The neutral safety switch is only for engine cranking. There is on the throttle an idle verification switch that interfaces with the ECM which could be the culprit. Then there is the C-Cruise which could be malfunctioning.
 
Tom, I knew you would chime in! Thank you. Is the C-Cruise the preselect cruise RPM switch on the panel? I had that on the 44 with my QSCs. I never used it. I can see how that could be suspect though. Ill pass it along. I will also suggest he follow the thread. He is more active over on the FB site as there are a bunch of MY guys on there apparently. I don't FB so I don't follow them.
Cheers
 
Carpediem44DB said:
I have a customer that installed one of my wireless remote helms on his 48MY which has the QSM 11 engines. He installed the system at the time he purchased the boat. He has had an intermittent problem on his starboard engine that so far no one has been able to trouble shoot. Some times when he selects either forward or reverse the engine will drop 200 RPM for a few seconds, then recover. He has had it happen in cruise at 1900 rpm but mostly it happens at idle when going in and out of gear. He contacted me to see if I thought it could have anything to do with my wireless helm control. Apparently some one suggested that the neutral safety switch or circuit could be the issue but I fail to see how really anything with the drive solenoids would cause a 200 rpm drop. I would suspect the electronic fuel control first. He has had a Cummins tech out to the boat but of course since this happens intermittently the problem could not be reproduced while the tech was there. Since he installed the system when he bought the boat he has no idea if the problem was pre-existing so he is going to disconnect the wireless helm for a time and see if the problem persists. Anyone here think that a drive solenoid or neutral safety switch wiring could cause this? I have the system on three other QSM 11 powered Sea Rays with no reported faults.
Click to expand...

This is that facebook post, right? I commented and said while I don't know the QSM well it sure sounds like a fuel delivery issue to me which could then either be a mechanical or electronic issue, of course.

The neutral safety switch comment seemed way off-base
 
upload_2022-8-19_11-4-8.png
 
He is going to start swapping components from port engine to starboard to see if problem follows as it seems unlikely to be an issue with the drive interface with the remote helm.
 
As a start he can swap the plugs across from the throttle assemblies which are remote from the throttle handles.
The throttle assemblies should be right next to each other so an easy thing to do. Here you can cee the bottom of the two on my boat. There are two wire plugs for each - one for the throttle potentiometer and one for the idle verification switch.
IMG_5150.jpg
 
Tom, I will pass that along. That's an easy and quick start especially if he does not need much throttle while maneuvering about. Other wise it could get confusing having the throttles swappedo_O. His big problem is the infrequency in which he has the issue. I don't know if he has done this but maybe he should simply disconnect every plug in the harness, clean, treat and reattach before he swaps port for Starboard. I think he has been concentrated on a drive issue since he did add a system to the circuit.
 
My QSM11’s Belts seem to create a bunch of dust on and around the Alternator. Is that typical for all of these motors/all big diesels or is my belt not adjusted correctly?

Rich
 
rlynch03 said:
My QSM11’s Belts seem to create a bunch of dust on and around the Alternator. Is that typical for all of these motors/all big diesels or is my belt not adjusted correctly?

Rich
Click to expand...
Mine do to.
 
I don't have QSM-11s, but on my 6CTAs, when dust started flying off of the belts, it was an indication that the belt tensioner was beginning to fail and it was slapping a bit.
 
rlynch03 said:
My QSM11’s Belts seem to create a bunch of dust on and around the Alternator. Is that typical for all of these motors/all big diesels or is my belt not adjusted correctly?

Rich
Click to expand...
Mine do too. I have checked the tension on the belts and I don’t want to go much tighter so I think it is the nature of the beast.
 
My QSCs did and so do my 6CTAs. Tension is correct and tensioner is good. Always wondered the same. Even new belts do the same. Not terrible, but always is some.

Bennett
 
My mechanic said it is typical also. Just wanted to see what you guys are dealing with… I guess there isn’t a cure.
 
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