Yearly maintenance on Cummins QSC

Zach312

Active Member
SILVER Sponsor
Jan 23, 2011
823
Nashville, TN
Boat Info
2008 Sea Ray 47 Sedan Bridge
Engines
Cummins QSC-600
Does any one have a detailed procedure for yearly maintenance items. I am new to tackling some of the yearly maintenance and want to ensure I don't miss something.

I have read through the QSC thread and most of the info here gets into belt changes, etc.

Looking for oil change and fuel filter process.
 
Does any one have a detailed procedure for yearly maintenance items. I am new to tackling some of the yearly maintenance and want to ensure I don't miss something.

I have read through the QSC thread and most of the info here gets into belt changes, etc.

Looking for oil change and fuel filter process.

The oil and fuel filter change process is very DIY friendly with lots of videos on YouTube. Do you have an oil change system like Reverso?
 
My rule of thumb for the diesel boats I've owned - lube oils and filters annually or 200 hours whichever comes first. Only twice have I put more than 200 hours on the boat in a year. All oils get sampled and analyzed every oil change. Filters are engine oil, fuel, coolant, and gear oil. The racor which is a double filter gets switched over and the one that was in use gets a new filter. Generator gets changed same time but usually has more hours. Every 5 years the coolants get sampled and the ELC adjusted as required. For the QSM11's the coolant filter has the ELC in it - they have three different levels available. That is pretty much the sum of the normal maintenance.

As a note on Cummins engines - fill and maintain the engine oil only to the low mark on the dipstick.
 
Set up an account at Cummins Quickserve. Lots of resources including the manuals that tell you what service and how to do it. Here is the general maintenance schedule for the QSC.

https://quickserve.cummins.com/info/index.html



Screenshot 2023-03-31 at 14.59.09.jpg
 
My rule of thumb for the diesel boats I've owned - lube oils and filters annually or 200 hours whichever comes first. Only twice have I put more than 200 hours on the boat in a year. All oils get sampled and analyzed every oil change. Filters are engine oil, fuel, coolant, and gear oil. The racor which is a double filter gets switched over and the one that was in use gets a new filter. Generator gets changed same time but usually has more hours. Every 5 years the coolants get sampled and the ELC adjusted as required. For the QSM11's the coolant filter has the ELC in it - they have three different levels available. That is pretty much the sum of the normal maintenance.

As a note on Cummins engines - fill and maintain the engine oil only to the low mark on the dipstick.
Oh Yea - on the raw water pump - I change the impeller every 5 years for the QSM11 but on my Cat engines they ate impellers and I had to change them every year. YMMV.
 
As a note on Cummins engines - fill and maintain the engine oil only to the low mark on the dipstick.

@ttmott why is that? I am under the impression that 1/2 on the stick is the target. As always, thanks for sharing your knowledge and expertise

Jaybeaux
 
In the Cummins engines windage is an issue. Keeps oil vapor down and seal leakage which is a Cummins issue (at.least on the QSM’s) at bay. There were a couple of threads on this here and on Boatdiesel. I confirmed with Tony Athens on my engines.
It’s 2 quarts in 7 1/2 gallons…
 
Thanks, Tackled the racors this weekend. I have been seeing different processes for the spin on fuel filters.

The oil changes seem a bit more straight forward.

For the spin on fuel filters do you prefill with fuel? I have seen some who do this and other who don't.
 
Thanks, Tackled the racors this weekend. I have been seeing different processes for the spin on fuel filters.

The oil changes seem a bit more straight forward.

For the spin on fuel filters do you prefill with fuel? I have seen some who do this and other who don't.
Do not prefill spin on fuel filters. The reason is you do not want any dirt past that filter, its other name is a "last chance" filter. You do want to put a little clean fuel on the o-ring with your finger to lube it though.

Oil filter you definitely want to prefill, that will take well over half a gallon of oil. You want to let it settle and top off for several minutes to get it as full as possible. Again, dab a little oil on the o-ring.
 
Do not prefill spin on fuel filters. The reason is you do not want any dirt past that filter, its other name is a "last chance" filter. You do want to put a little clean fuel on the o-ring with your finger to lube it though.

Oil filter you definitely want to prefill, that will take well over half a gallon of oil. You want to let it settle and top off for several minutes to get it as full as possible. Again, dab a little oil on the o-ring.

Makes sense, Is there a processes to get the air out out the filter?
 
Lube fuel filter gasket with a bit of fuel.....install fuel filter EMPTY....open the outlet plug on top of the fuel filter with hex key. Turn on the ignition keys, and then cycle the engine start/stop switch to the first indent, and leave it there until the fuel pump quits running. Turn off the switch, and let sit for 10 seconds or so while the SmartCraft "resets". Then repeat. If I remember correctly, it took 12 or so cycles on one engine, and less on the other. Monitor the vent plug for fuel and tighten up when fuel squirts out.

Jaybeaux
 
Lube fuel filter gasket with a bit of fuel.....install fuel filter EMPTY....open the outlet plug on top of the fuel filter with hex key. Turn on the ignition keys, and then cycle the engine start/stop switch to the first indent, and leave it there until the fuel pump quits running. Turn off the switch, and let sit for 10 seconds or so while the SmartCraft "resets". Then repeat. If I remember correctly, it took 12 or so cycles on one engine, and less on the other. Monitor the vent plug for fuel and tighten up when fuel squirts out.

Jaybeaux
Does anyone happen to know the size for the Hex key. How much fuel needs to be purged in order to ensure all of the air is out?
 
Hex key size: Sorry, don't remember. I just had my Standard and Metric sets and began the hunting game.

I let fuel bleed out until it is no longer bubbling. It really isn't much as you are essentially filling the spin on filter from the bottom, letting it pass through the filter media into the center tube, then out the outlet.
 
The QSC is self priming. No need to open the hex key and let fuel bubble out. Just turn the key on, listen for the lift pump to run and stop. Do that several times (I usually do it 5 times, the manual states 3 -4 times). Start the motor, it will run rough for a short period of time, then smooth out. Do not under any circumstances fill the on-engine fuel filter with fuel prior to installing. A piece of grit smaller than you can see can damage an injector.
 
The QSC is self priming. No need to open the hex key and let fuel bubble out. Just turn the key on, listen for the lift pump to run and stop. Do that several times (I usually do it 5 times, the manual states 3 -4 times). Start the motor, it will run rough for a short period of time, then smooth out. Do not under any circumstances fill the on-engine fuel filter with fuel prior to installing. A piece of grit smaller than you can see can damage an injector.

Thanks. Where does the air go in a self priming system?
 
You only have to go through that process if you have done work that introduced a lot of air into the system like replacing an injector. If all you are doing is replacing the on engine fuel filter, just follow the procedures in the engine manual.

Screenshot 2023-04-07 at 15.51.19.jpg
 
I always just crack the filter a bit to bleed the air as the lift pump primes it. Once it fills to the top screw it down and all good. Never had an issue.
 

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