[Curtis J McNamee]

Hi Tony- Yes, I totally agree that a lot of mechanics and owners of QSM 11 engines do not understand any of this….the last owner and his mechanic that maintained these engines since new in 2002 had no idea….3900 hrs with no maintenance on the exhaust system or coolers and heat exchangers….

I did post the RPM/fuel burn on this boat from the sea trial on this forum and we all agreed that the boat was over propped.

In the mean time, while waiting for haul out….we had this total exhaust system breakdown and engine fire from a blown exhaust gasket.

The boat is on the schedule for haul out on the 9th, the props will be pulled and repitched to achieve the correct fuel burn per your article.

Thanks for all your help and writing great articles about problems that we are exposed to.

Will repost when the props are done and we can run the boat again.

Cheers,

Curt

[Curtis J McNamee]

Yes, that is what it looked like to me….I will see what the bottom looks like when we pull her out.

[Curtis J McNamee]

Thanks everyone for your input, it is very much appreciated.

Cheers,

Curt

[Curtis J McNamee]

Tony Athens wrote:

Other than the Oil analysis, any other symptoms that would lead you to believe your engine needs rebuilding? Measured High blow-by, high oil consumption ( maybe over 1% of fuel used)?, very hard to start when cold ( even with good batteries) , or ???

The QSM typically does not just “wear out” unless it is being operated at 20-22 GPM load on a 60-80% duty cycle and/or it not being maintained– and then you would have to have run 75,000 ++ gallons of #2 thru it…Remember, this is a 2,000,000-3,000,000 mile + truck engine with solid roots going back to before 1998..

Tony

Hi Tony- thanks for the response…..no other symptoms and this is a head scratcher for sure. It starts right up, no smoke, normal oil consumption and fuel burn.

Could the Chromium be coming from valve stems and out of tolerance clearance with the rocker arms ??

Curt

[Curtis J McNamee]

Rob Schepis wrote:

Curtis J McNamee wrote:

not sure about the propping or how the engines have been run in the past.

You did a seatrial, no? You must have if oil samples were taken. With the boat as heavy as possible, you need to record the fuel burn at rpm increments throughout the rpm range from hull speed and beyond. And then go here:

https://www.sbmar.com/articles/propping-cummins-qsm11-to-prevent-exhaust-leaks/

Yes 250hrs is a bit stretched on the oil change interval. What oil filters are currently fitted?

Hi Rob- Yes, we did a cold start, sea trial and oil samples were taken, the boat had almost full fuel…800 gals. I did look at the fuel burn as we moved up thru the power settings but did not record them. How does that effect what we are seeing in the oil sample results ?

[Curtis J McNamee]

Rob Schepis wrote:

If all else was normal that one level alone does not appear to be alarming. Was a blow by test done? Cold start? How was she propped throughout the rpm ranges?

Hi Rob- Thanks for the input…I am having compression and blowby tests done next on these engines to see if we can find anything obvious.

Cold start and the lack of smoke are really good, not sure about the propping or how the engines have been run in the past.

What is the recommended interval for oil changes on these engines….seems like 250 hrs is excessive…

Curt

[Curtis J McNamee]

Paul Hoffman wrote:

I have the same engines (1999) and about the same size boat – I’m running with two 24X26X4 on a 2″ shaft with a 6″ hub. Might not be your answer, but hopefully something close.

Hi Paul- My props are 24X24 also on a 2″ shaft

[Curtis J McNamee]

Hi Tony- First….thanks for having this site and helping us all out with questions !!!

I will gather more information about my engines for you and post it on this thread.

Cheers,

Curt

[Curtis J McNamee]

Hi Rob- I have an oil seal leak in my starboard turbo and my injectors have never been serviced…hard starting, smoke indicates unburned fuel.

Cheers,

Curt

[Curtis J McNamee]

Hi Rob- Thanks for the feedback….I know my tachs are not reading correctly so I have strobed the shafts and created a correction RPM table ( I would like to install digital Tac’s)…any suggestions ??

I am currently having my injectors and one turbo overhauled and installing a fuel flow system, once I have that done I will see what I have.

My props are tired and need to be replaced (I will keep them as spares) My goal is to get new props that are set up properly for my engines.

I typically run my boat at 14-1600 rpm, I like the slower pace…I am not in a big hurry and it saves fuel and keeps me in a position to see logs and crab pots.

Towards the end of my run, I will power up to bring the engines to temp and run that way for 5 minutes or so as many have recommended.

Thanks for the help !!!

Curt

[Author]

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