I have a 545 XP Husqvarna will start and run but won't idle

Carb idle mixture and idle speed adjustment might do the trick or it might need a carb stripdown and clean before readjustment. The carb diaphragm can be affected by long immersion in fuel and lose flexibility and in that case replacement is advised.

There is a small chance the vacuum pulse from the engine crankcase isn't strong enough to keep the carb supplied with fuel at low rpm.
This isn't unusual and usually happens when a 2-stroke engine has been idle for a while, such as over winter. It was running fine last season but now it simply won't behave.

In that scenario it is possible the crankshaft seals have lost flexibility and air is being drawn past them reducing crankcase vacuum...

It works best with very thick fabrics when the bottom fabric moves with the feed dogs but the top fabric doesn't, ie quilts. Also, helps when sewing slick fabrics.

I just got a great answer to the same question. If you are sure the cord is conducting electricity it may be the contacts in the machine. Check for lint on pins. If they wiggle a little you may have to remove back and tighten the screws that hold the machine wires in place.

http://www.mediafire.com/download/41yw6t6yevww664

try a new needle
if the needle is still hitting the needle plate, then it's possible that the machine is out of time and needs to be adjusted, or there is something wrong with the needle bar.

Replace the fuel filter in the tank, check the fuel hose up to the carb for signs of leaking, if so replace the line, between the cylinder and the carb back plate is a rubber induction tube, make sure this has no split.

run both scrwes all the way in and them back out 2 and 1/2 turns. thats a good starting point. adjust the low while idling and the high with the throttlr wide open.

Many Viking machines do not require oiling. Viking does have manuals online for many of thier machines, I don't know which ones specifically.

Sounds like dirty carberator or carb needs adjustment. How is the spark plug?

I use an Omnibook 500 with a Jornada 545 as you describe without problems. The most likely cause is the difference in processors. The first version of Pocket PC was supported on three different CPU architectures. The Jornada 545 uses an SH3 processor. Applications designed for the 565 will not run on the 545. You will need to find applications designed for the SH3 processor.