QSM 11 661 hp - Major Service Questions

Good morning, all. In April I purchased a boat with twin Cummins QSM 11s, rated at 661 hp. The engines are 2005, and they had 790 (port) and 815 (starboard) hours. The previous owner had the boat for about 6 years. I have all of his service records, and I followed up recently with the selling broker to make sure there wasn't service performed elsewhere. With that, I confirmed the PO had done annual "basic" maintenance: oil and filters, zincs and impellers when needed, but that's about it. No evidence that aftercooler was ever scoped or pulled, gear cooler was serviced, or other major items.

Since we took possession, we've put nearly 150 hours on the engines. They've run flawlessly. The starboard engine needed about a quart of coolant added, and between the two engines I've added about a gallon of oil over that time. Exhaust is normal, oil color is normal, temps are normal and stable, rpms, everything runs as one would hope.

We're a planing hull, so I'm running at around 2000 rpms. Engines are slightly underpropped, so I can hit the 2350 limit with a normal load (two of us plus regular provisions). I like it that way.

Long story short, in light of the lack of evidence of major service, I've got a reputable Cummins mechanic scheduled later this month. They've got seven days scheduled to do the work, hoping to complete it in five days if all goes well.

For those with these engines, is there anything in particular I should be asking them or looking for? I've read everything on the Seaboard Marine site about these engines, and talked to the Cummins tech that surveyed the engines for me, but this service is a big "investment" and I don't want to miss anything obvious.

Thanks in advance.

Might be helpful to post the list of what they plan to do, service and replace. Many manufacturers have a 1,000 hour maintenance schedule. Was the boat in fresh or salt water? If saltwater, I might add transmission coolers to the replacement list if the original ones don't have anodes.

Ted

What does the engine manual say about maintenance intervals and what needs to be done?

My 2c. I think they are great engines when loaded correctly. The biggest potential issue with the dry manifold QSM11s are manifold cracks. If you have read the info at Seaboard Marine, you are aware that they should not be loaded beyond 19 gal/hour at cruise (about 400hp). I'd make really sure you don't exceed that fuel flow at your 2000 rpm cruise and not just in flat water. Climbing ocean swells can easily put you over the top.

Sorry for the tardy responses...long work day.

Gsholz, I just re-read all the Seaboard materials this past weekend and have the "chart" Tony has shared w/ fuel burn @ various RPM. I'm heading out this weekend and going to compare my results against his recommendations.

High Wire, with regard to service intervals, any way you look at it (engine hours or years), I'm due. Likely overdue as the "big" intervals are four years, and the records I have go back to October 2014 without any of the major services being done.

OC Diver, in addition to oil/filter changes, tear down / inspect / service aftercoolers and heat exchangers, valve adjustment, service gear and fuel coolers, replace impellers, and anodes/zincs. The parts estimate is about $3,300, but that includes items that may not be needed (e.g., there's an allowance to replace both raw water pumps...probably not needed.

BroadCove said:

Sorry for the tardy responses...long work day.

OC Diver, in addition to oil/filter changes, tear down / inspect / service aftercoolers and heat exchangers, valve adjustment, service gear and fuel coolers, replace impellers, and anodes/zincs. The parts estimate is about $3,300, but that includes items that may not be needed (e.g., there's an allowance to replace both raw water pumps...probably not needed.

Click to expand...

Since you don't know me, I suffer from CDO. That's OCD (Obsessive Compulsive Disorder) in alphabetical order as it belongs to be.

I generally do most of my maintenance, so I only pay for parts. My goal is to make my single engine boat as reliable as possible. So, if you're serving the cooling system after 16 years, I would replace the thermostat, radiator cap, and probably the engine water pump. While I was under the belt guard, I would replace the serpentine belt, maybe the idler pulley and maybe the belt tensioner. In addition, I would consider changing or atleast inspecting all the coolant hoses. The point that I'm making here is that a failure of many of the parts, can lead to overheating and a much more expensive bill. Get an estimate for some or all of these to see how it effects the price. On some items, the cost of the part is smaller compared to the labor for only replacing that one part. As an example, the idler pulley is replaced by removing one bolt and installing a new one. But if you're not already working on the front of the engine, the belt guard and belt need to be removed first. The Thermostat is pretty simple to do if you have already drained the antifreeze.

I would want to know the difference between servicing / cleaning the gear cooler and replacing it. If it doesn't have an anode (the factory ones generally don't), I would probably replace them as the electrolysis from lack of an anode, can't be repaired.

Respectfully, do you do any of your own maintenance? How far from home will you travel with the boat? My point here is that if you can't do the repairs yourself, replacing things like the engine coolant pump, can be done at a time and place convenient to you, or not. As you venture further from home, you may not find a service professional as easily.

Some gears have an oil strainer screen. I would want them pulled and cleaned. There is probably nothing in them, but if there is, I would rather rebuild a gear than replace it.

Finally, even if you can't do the work yourself, having the correct parts onboard could be the difference between being stranded and just loosing a couple of days.

Spares I would have included one of each:
Starter
Alternator
Raw water pump
" " " impellers
Engine coolant pump
Thermostat
Serpentine belt

Ted

I'm surprised no one has talked about sending out oil samples. I think you have a great set up. Planning hull that cruises at 2,000 rpms. By building a history of oil samples every 100 hours your engines will let you know about any issues well in advance.

Tiltrider1, great reminder...I "assumed" an oil analysis, which is always a bad idea. Just added it to my actual list. The only analysis I have at this point is from the initial survey, which was on clean oil.

Ted, thanks so much, that is an excellent list of items to check/replace and spares to keep aboard. It also thankfully tracks most of what they have listed as anticipated parts...two raw water pumps, two thermostats, impellers, and much more. I'll add to my collection of spare parts that came with the boat (which I need to inventory anyway).

Good question re: doing my own maintenance. I'm handy, but this service is out of my depth. The bigger factor though is I still work full time, and my time is more valuable to my company than it is in the engine room. That said, I do work remotely, and plan to be on the boat for the time the mechanic is around. I'll stay out of the way but hope to learn a good bit while he's doing the work.

It's important to understand that spares have a limited life also. If you have spares of items they are replacing, you may want to have them install your spare and put the one they are selling you in your spares. Things like serpentine belts, thermostats, and engine coolant pump come to mind.

I would be suspicious of old raw water pump impeller spares. Ones that are over 5 to 7 years probably should be pitched. They don't age well and the cost is small compared to the labor to install.

Regarding oil analysis:
I'm a big fan and do both engine and gear every time. When bought in bulk (6) from Blackstone Labs, my total cost is $25 per test. Down the road when you eventually sell the boat, oil analysis speaks volumes with regard to condition and routine maintenance.

Ted