QSM 11 Running Warmer than Normal

[Bob Hill]

I have 2 QSM 11 635 hp engines. They are 2002 with about 650 hours. They have both been running right a 180 degrees at 2000 rpm (normal cruise) for years. The port engine has started to climb. A few weeks ago on a 6 hour run it was running about 185 degrees. This past weekend on two 3.5 hour runs it ran at 190 degrees. I am going to replace the raw water impellers (on both) and was thinking that perhaps I should switch to the 160 degree thermostats as well. Is the thermostat switch a good idea? What else might be causing the temp rise? Thanks in advance, Bob

Topic

[Rob Schepis]

QSM11 Stats and Seawater Side Maintenance

The 160 Stats should be in the QSM11 marine engine from the factory. All the way from 1999 to present, wet or dry version.

Part numbers 4952210 or 4973372 ( starts to open at about 159F, fully open at 174-ish).. On highway and industrial stuff use the higher temp stats

AND,

I revert to Corey’s post above that chances are the cooling system needs to be Properly Serviced Top to Bottom…sounds like all is original with well over a decade of Marine Age on it.

[Larry Backman]

Isn't the standard QSM thermostat 165?

My old QSM opened at 165 and stayed between 165 and 169.

My new QSM opens at 163 and stays rock solid at 167.

[Corey Schmidt]

Seawater components

Bob, when is the last time you have serviced/inspected the engines main seawater components?

• Aftercooler
• Heat Exchanger
• Gear Oil Cooler
• Fuel Cooler

This would also include inspecting and replacing the seawater pump impellers… when you replace the impellers, inspect them carefully to ensure that no veins have gone missing, etc.

Event though these are LOW HOUR engines, they have still been around for 15+ years… MARINE AGE is what takes them out.

Let us know…

PS – Do you have any pictures of the engines as they’re installed in the boat?

[Author]

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