In this contribution we consider how open source innovation impacts the definition and evolution of Business Models. Open source innovation constitutes a specific case of innovation. Specific rules guarantee a free access to enable a collaborative work between numerous contributors. These rules impact the value creation and appropriation. The openness may favor creativity and adaptation to the innovative and turbulent environment. However, the contribution of numerous participants may also constrain the BM decision concerning the capture of the value collectively created. In order to identify how open source innovation facilitates or limits the adaptability of the BM to evolving environment, we realize a deep case analysis. We examine a situation where an open source project has been initiated, then supported then reorganized under different forms. We sequence the recombination of the BM components, and qualify the supporters and the hinderers. We observe that initiators, institutional managers, users or contributors may appear as facilitators or breakers of business model changes. We describe the range of actions all these actors perform in order to push or avoid the BM dynamic. We finally show that openness in innovation goes with a smooth management of external contributors.