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Old 04-25-2016, 01:50 PM   #1
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Cummins QSC 540 in 2006 Mainship 430 -- Opinions

Ok -- I'm looking (at point of engine surveying) a 2006 Mainship 430 with Cummins QSC 540 engines with only 600 hours. I'm hearing good and bad. I understand that Cummins went from the 540 to the 550 -- 1) b/c it simplified parts for their engines; 2) that there was a problem with the 540.

I need some expert opinions on this from people who have knowledge about this.

Any help is appreciated.

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Old 04-25-2016, 06:54 PM   #2
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I don't think that was the series that had problems. Either way, 600 hours is nothing for those engines. A qualified Cummins tech/survey would put your concerns to rest.
If I recall, it was the 600 HP engine with the smaller block that had issues. Go to Seaboard Marines website (Tony Athens) for the real skinny on these.

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Old 04-25-2016, 07:34 PM   #3
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Go to and pay the $25 and ask your question there. Generally most QSC's are the same engine...just tuned differently for different duty and ratings. But pay your money on Boat diesel and then search and search and then ask your question if you don't find your answer.

That is a helluvalotta engines for that boat. I have seen that boat with QSM11s too I think. It was funny because the broker came out and I asked him what was the cruising speed. And he said, "8 knots"!!!!! I was like....oh really....almost 1300hp and all it does is 8 knots???!!!! Anyway, I got quite a chuckle.
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Old 04-25-2016, 07:43 PM   #4
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I had QSC 500s in my Grand Banks and they were completely trouble free. You need to look out for a couple of things. First, find out if the aftercoolers have been serviced. If not, knock off a few boat bucks from the purchase price and put that on your list for immediately after you buy the boat. When you get the after coolers services, make sure it's by someone who knows what they are doing. They need come completely apart, be cleaned, new o-rings, greased like crazy so they will come part the next time, pressure tested, and reinstalled. If you want you can sent them to Tony Athens for service. Remove and reinstall isn't too hard.

The other thing to check carefully is to see if the boat is propped correctly and whether the engines have been overloaded. That will kill a good engine very fast. Look up the rated RPM for that exact model QSC, then sea trial the boat at wide open throttle. The engines should EXCEED rated RPM by 50 RPM or more. This should be possible with full fuel, full water, everything on board. If they can't get over rated RPM, then they are overloaded.
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Old 04-28-2016, 09:32 AM   #5
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IMO you need a new mechanic
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Old 04-28-2016, 10:06 AM   #6
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Originally Posted by bayview View Post
IMO you need a new mechanic
Not sure what part of the thread you are referring to. Who needs a new mechanic, and for what?

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cummins 540

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