QSM Exhaust Leaks

[Rich Dancaster]

I am looking for opinions from current QSM 11 owners, given the manifold leak issue and no for sure fix, if armed with this knowledge would they purchase a boat with QSM 11s?
Note: Subject boat I am considering purchasing, has QSM 11 @ 610HP and 1050 hours. Starboard engine just had the manifold gaskets replaced (Cummins parts, gasket + new bolts and spacers using CAT gasket cement) due to a small leak by the #1 cylinder. I plan to have the prop pitch reduced to stay in the QSM prop curve as Tony suggests. Also any history on similar repairs?

Thank you in advance for your feedback.

Topic

[Tony Athens]

Just so all know Skipjack’s back ground….

Larry has been though this all over many years on his own wallet and knows this stuff like no other.. Think of him as the “Gospel” as to this engine and it’s quirks……………….. But even better, he never complains even though it has cost him dearly..

My hat is off to him..

Tony

[Rich Dancaster]

Exhaust Leak

Good information! Thank you Skipjack for the insight. Combining the manifold with the cooler service is a sound idea.

Cheers

[Larry Backman]

I did both

Replaced a QSM 11 leaking manifold with a new manifold, notes and gaskets at ~600 hrs. The engine was at 2800 hrs when it was replaced for other reasons and the manifold had not leaked. This was done by a B level yard and a rookie mechanic.

I have a new recon QSM 11 which had an exhaust manifold leak at 175 hrs. Cummins replaced manifold, bolts, baskets, etc and as of yesterday I am at 700 hrs, no issues.

I run my engine at 18-19 GPH, watch EGT carefully and as painful as it may sound, will treat the exhaust manifold as a 3 year/2000 hr wear part that needs to resealed when the coolers are off for servicing.

FWIW – Cummins tech had engine apart and manifold off in 5 hrs, and put it all back together in 4.5.

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Rob Schepis

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