QSC 8.3 RPM Surge

[Steven Williford]

I have a single QSC 8.3 (2007 model with 2500 hours) that is experiencing infrequent and inconsistent RPM surges of 30 to 40 RPM. Engine has a Morse KE-4 electronic engine control and also the CM SmartCraft instrumentation. I generally run the engine at 1300 RPM for 7 to 8 knots and a resultant 3.6 gallon/hour fuel consumption. When it surges it will pop up to 1340 or so then fall back to 1300. It never fluctuates downward.

The previous owner also suffered from minor RPM surges and eventually replace all the injectors a couple of years ago. Some days I have no surging at all, some days it will surge infrequently and then stop for the balance of a run. My feeling is that the KE-4 is subject to some type of electro-magnetic interference (EMI). Could be from the 12 VDC or from the inverter and 120 VAC (maybe the refrigerator compressor kicking on). A search of the internet has turned up no references or reports of EMI and the KE-4 controller.

Has anyone had any experience or have advice on this irritating little problem? Or a solution? Alternatively I could be way off base with this whole EMI theory.

Topic

[Tony Athens]

What type of digital displays do you have? Bring of the screen that shows throttle %, and watch that during the RPM fluctuations…………….If it changes, then you have an KE-4 issue.. If not,then I’d say you have an engine issue or sensor issue.

Tony

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