Running pump at lower throttle RPM.....damage?

Doing research I came across comments of damage to the pump at lower RPMs. Can anyone verify this ? I’m going all in with a 8gpm 3500psi. I’ve read about adjusting with the tip size but would still like to know if lowering the RPM will lower my gpm and not harm the pump.
And I’m a mechanical guy so the more of “this will cause that” the better.
Thank you for your advice in advance.
Venice FL

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Air cooled engines are made to run throttle wide open. Idling down causes over heating. Adjust your pressure with nozzle tips

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I get that air cooled needs to run as designed rpm. Will it damage the pump ?

No. As long as your feed flow to the pump isn’t compromised it will be ok.

Your best bet if you want to reduce your flow in certain situations would probably be choking it with a ball valve at the gun. That should cause some of the water to bypass back to the tank (provided you have a pressure trap unloader, as opposed to a flow actuated one).

I tried the idle-down method recently, and I was kind of surprised at how little a difference it made (I managed to get my 5.6 gpm machine to put out around 3.5, at just above idle). Also, running the motor too slowly will cause it to stall when the the unloader kicks in, unless you turn the unloader way down