Income excluded under the FEIE is not compensation that will support a Roth IRA contribution. However, the income excluded under the FEIE is added back to your AGI in determining your modified AGI used to determine the maximum amount that you are eligible to contributed to the Roth IRA. Even though you may otherwise have sufficient net earnings from self-employment income to support a larger Roth IRA contribution, the maximum that you can contribute to a Roth IRA for 2017 can be limited if your modified AGI is in or above the phase-out range:
https://www.irs.gov/retirement-plans/amount-of-roth-ira-contributions-that-you-can-make-for-2017
