6CTA and QSM11 engines. How easy to reach/change the impellers?

[John Easley]

Hello,

New member here. Just found this incredibly useful site. Hoping you might be able to answer a couple of questions.

We are considering moving to a larger boat. Two are under serious consideration. One is a 53′ with 6CTA 450 hp engines and the other is a 57′ with QSM11 635 hp engines. How easy is it to access the impellers on these two engines without removing the raw water pumps? (Our current boat has 6BTAs 330 hp and the left front engine mount is in the way) Are there any close up photos that show how easy it is to access the water pump cover plate?

Our understanding is that the QSM11 is a dry exhaust and dry turbo system. I’ve ready your article about preventing exhaust leaks. https://www.sbmar.com/articles/propping-cummins-qsm11-to-prevent-exhaust-leaks/

Our routine is to run at about 8.6 knots or 10 mph for good fuel economy for most of a trip. We’ll get out into open water (wide river, bay, Gulf or ocean) and crank it up to cruising speed for five or ten minutes to blow out the turbos and get up on plane, then slowly ease down to hull speed for the remainder of the day. How would QSMs do under such conditions? Would that kind of treatment be harmful to them?

Thanks for any advice or tips.

John

Topic

[John Easley]

Hi Tony,

Your reputation is obviously deserved. Thanks for the information and the photos.

The 6CTA looks easy to work on, easy access.

The close up photo of the seawater pump on the QSM looks like the dipstick tube and the oil filler tube could be in the way of using an impeller puller. However, the overall photo taken from the front left corner of that engine makes it appear as if there may be more room to work in between the seawater pump and the oil filler tube. What are your thoughts? Easy enough to pull the impeller, assuming there is room to squeeze my body in there?

[Tony Athens]

John,

Impellers changing: Both the 6CTA and the QSM 11 have plenty of clearance around the pumps.. But how easy to change them will be most influenced by the access in the boat to the pump and your resolve and or experience..

If the QSM11 is propped per my recommendation, you will have NO ISSUES running it the way you propose..

Some pics attache for both engines.

Tony

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