Ignoramus17028 wrote:
....
First Question: the engine goes faster and slower every 6 seconds or so,
maybe varying speed by 30%. Why would that be the case.
....

You've replied that this happens when the washer is just sitting, not
spraying, you think. I have a 5 hp gas washer that had a problem
cycling while spraying. It was very annoying. I discovered that the
nozzle was partially clogged. This caused the bypass/diverter to open
because the high pressure looked like the wand valve was closed. But
there was enough flow to close the diverter and start the cycle again.
Keeping the nozzle clean stopped the cycling.

HTH somebody,
Bob