I'm trying to help out an old friend, he is wondering if there is a way to adjust idle speed. Any help is appreciated.

The idle screw is on the back side of the pump (head side), you would screw it in to raise the idle and screw it out to lower it. I believe the lock nut on the screw is 10mm.

Here is a picture showing the idle screw.

Thank you bjytech

bjytech is right. The 10mm wrench will loosen the nut (maybe) like a few I've worked on I've had to use sockets and one I used a screwdriver and hammer to tap the nut to loosen. Make sure you snug that nut back up again. It might be the governor spring getting weak with age why the idle is sagging down.