I have been getting some lessons this week on pump engine vibrations. I am sure you all want to share in this. Tim at Arms Pumps in Berkeley rebuilt on of our pumps and installed an anti-vibration device to it. It seems that under 1800 rpm the vibration from the engine that drives this pump can cause excessive wear to the spline connecting it to the pump. Normally we run the pump at 1800 rpm or above but there are times when we need 'only' 250 gallons per minute and we slow the pump down. It is at these times that the bad vibrations from the engine tears the pump apart.
With the rebuilt and improved pump we can still work at lower volumes, save water and get our pump to last longer.