QSM longevity question

[Bill Desmarais]

Posting for a downeast boats forum member

Engines are in a 2000 39′ Liberty Express. 6,500 hours. Port Engine has blow by, so repowering both engines. See details of each engine below. Boat in water until December 1, available for sea trial.

Starboard Engine:
Cummins QSM11 Marine Diesel Engine with 6,500 hours.Included is a ZF gear with 1:1.485 gear ratio.Currently in boat, available for sea trial until December 1. Motor is strong, new injectors, fuel pump, alternator.Recent exhaust manifold, gaskets.Recent service to aftercooler and heat exchanger.This is one (starboard) of two available.The other one available (port engine) has blow by, but still makes good power, and is available too (make offer).Re-powering boat with two new motors.
Serial Number 34959229

Port Engine:
Cummins QSM11 635 HP Marine Diesel Engine. 6,500 hours. Has blow by, but still makes 2,350 rpms. New injectors, exhaust manifold, turbo, fuel pump, alternator. Gear may be available. Currently in boat and available for sea trial until December 1. One of two available. Other with same specs/info, runs strong. See other listing for details on other motor.

Serial Number 34960257

Just saw this after coming back from NY for a getaway.
At 635 HP, what is the consensus of 6500 hours on a QSM?
Maintenance would factor in but how many hours would be best I could hope for. I would only do 150 per year max anyhow and might be willing to take the chance if a mechanic said all ok.
I think these are on Boat diesel also.

New price. $15,000 for starboard engine. Make offer on port engine.

Topic

[Tony Athens]

If I wanted to do a simple check, I’d also unplug the boat from the dock a day before too..That will take any “top charge” off the batteries……… OIL PAN should feel really cold……….Then, just see how they start.. If below 40F and they start up within 5-7 seconds, things are good.. Above 50F, quicker, Above 60F, quicker yet.

Tony

1 user thanked author for this post.

Richard Lynch

[Richard Lynch]

Stone Cold Start

Tony:
Above you mentioned that the way a QSM starts from a 48 hour Stone Cold Start means alot.

Can you elaborate on how it should start and what the tell tale signs are if it is not good?

Thank you

Rich

[Tony Athens]

Simple answer & more ???’s…..

1— All engines have “blow-by”, so it comes down to the amount? How was it measured?

2———— “Blow-by” can just about always be contained or mitigated to where it is out of sight and out of mind, especially on a QSM.. How well that can be done will depend on mow much room he will have above the engine once installed–If a 12″ or more, then it quire easy.

3—————-How well do the engines e start when “stone cold” from a minimum 48 hours soak??. Back east that should be and easy check and will be just about the best indicator of internal health one can perform.

4————————-Got some good pics from all around?

Tony

[Author]

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