You can use them with the electric start motors as long as you do not need the electric start function. Cables are around 9' and 10' long. Condition: Both levers and cables move pretty easily. I'm not sure if the paint on control housing is original. There are no broken or cracked parts.
Rubber cable housing looks OK, but it's 60+ years old. The item "Vintage Mercury Quicksilver Kiekhaefer Outboard Motor Controls'50's Mark 25 30" is in sale since Tuesday, April 23, 2019.
This item is in the category "eBay Motors\Parts & Accessories\Boat Parts\Controls & Steering". The seller is "johnnyvox" and is located in Rochester, New York. This item can be shipped to United States, Canada, United Kingdom, Denmark, Romania, Slovakia, Bulgaria, Czech republic, Finland, Hungary, Latvia, Lithuania, Malta, Estonia, Australia, Greece, Portugal, Cyprus, Slovenia, Japan, China, Sweden, South Korea, Indonesia, Taiwan, Thailand, Belgium, France, Hong Kong, Ireland, Netherlands, Poland, Spain, Italy, Germany, Austria, Bahamas, Israel, Mexico, New Zealand, Philippines, Singapore, Switzerland, Norway, Saudi arabia, Ukraine, United arab emirates, Qatar, Kuwait, Bahrain, Croatia, Malaysia, Antigua and barbuda, Aruba, Belize, Dominica, Grenada, Saint kitts and nevis, Saint lucia, Turks and caicos islands, Barbados, Bermuda, Brunei darussalam, Bolivia, Egypt, French guiana, Gibraltar, Guadeloupe, Iceland, Jordan, Cambodia, Cayman islands, Sri lanka, Luxembourg, Monaco, Martinique, Maldives, Nicaragua, Oman, Pakistan, Paraguay, Uruguay.