i have sears model engine 143.004502 i have carb idling issues not sure if linkage is right it idles poorly but all of a sudden it runs full speed have to shut off so it idles down. something tells me it might be electrical??? shop book will tell me how to adjust properly. any PDF manuals for this model thanks
sears917.388222 push mower 4.5 horse

I think the manual below covers your engine. Have a good one. Geo
http://www.cpdonline.com/692509.pdf

Sounds like the linkage from the carb to the governor, or the governor return spring may be the culprit.