Hi Gabi,

You may find the Colt 8's Briggs and Stratton engine operator's manual and illustrated parts list useful.
Operator's manual:
http://bsintek.basco.com/BriggsDocumentDisplay/msozHP-K_ny7tH217FzoPu.pdf
Illustrated parts list:
http://bsintek.basco.com/BriggsDocumentDisplay/Z6nlxBVJ1DajI.pdf

It would help if you tell us what your husband did differently between when he thought he had no spark, and when the engine started. Then we would all be on the same page. It appears that either he had accidentally grounded the kill wire the first time he tried it, or it wasn't lack of spark. I could hazard a guess as to what was wrong: he wasn't sitting on the seat, so the kill wire was being grounded by the mower's seat safety switch. That is what happens in many of the cases of mysterious ignition failures on ride-on mowers that we get at Outdoorking. In your case I think the dealer will have bypassed the seat safety switch when he was showing you that it runs, then he will have (quite properly) reconnected the safety switch before you took the mower away.

By the way Gabi, welcome to Outdoorking. I hope we will be able to help you in the future, hopefully at least sometimes before you or your husband fixes it yourself.