The mounts are different side to side, pax side mount is taller, and almost never wears out. Driver's side is the one that always goes bad, and it's also the one that's easier to get (available aftermarket) -- the RH side IIRC is available only thru Volvo. LH mount is part # 1229803 and you should be able to find it without any trouble. If the motor is sitting wrong, then that prob means only the one side has a bad mount -- I'd start by changing the driver's side and see if that does the job.
Adjusting idle speed can be a little fussy since there's more than one place you need to look at. The idle *should* be set by the stop screw on the top of the pump that stops the throttle lever (it's the inner one, towards the engine, under the aneroid housing that looks like a spaceship on top of the IP, with slightly difficult access). However, especially in cases where you have inadvertently raised the idle speed by changing the setting of the fuel quantity screw (which, as you have likely discovered, has a pretty large effect on low idle speed), it can happen that you back that idle stop screw down far enough to where the throttle cable pulley hits
its low stop too, and then that will prevent the idle from coming down any further since the throttle lever will not be able to reach the low speed stop screw on the pump top. What you have to do in that case is either lengthen the pull rod that connects the bottom of the pulley to the IP throttle lever, or, preferably, move the ball stud on the lever further inwards. Reason I like the second option better is that lengthening the rod then affects your ability to get all the way to the high-idle stop (aka "full throttle"), so you then are running into problems on the other side.
The bulb socket should be a cheap buy in whatever place you look for it -- if you don't want to pick one from the JY, might try looking on ebay or placing a wanted ad here or on another Volvo board and having someone send you one. In fact, I probably have a few I could part with -- you can pick one up if you're in the area, or I can drop one in the mail, if you don't have a better option.
