Brian Klawiter owns Dieseltec shop in Grandville.
In a statement this week on his company Facebook page, he urged gun owners to visit his business, promising a discount for those who do.
"Enough is enough," his post said, declaring that the voices of conservative Americans are getting drowned out. He pledged to operate his business the way he sees fit.
"I am a Christian. My company will be run in a way that reflects that. Dishonesty, thievery, immoral behavior, etc. will not be welcomed," he said. "I would not hesitate to refuse service to an openly gay person or persons. Homosexuality is wrong, period."
In a followup post, he said those who oppose his views can do so -- without threatening to kill his family and friends.
"I will stand firm on my views and will not back down," he said.
Klawiter said conservative Americans are entitled to free speech, too.
"Apparently if you are white (or close to it), you have a job, go to church, and own a gun ... That translates into racists, privileged, bigot, conspiracy theorist. Too many of us say nothing. Well, freedom of speech isn't just for liberals."
Klawiter told CNN affiliate WOOD TV he had to contact local authorities
after protesters showed up at his home. He said he's received death threats and hundreds of calls from all over the country.
He said he's not asking customers about their sexuality, but same-sex couples who exhibit affectionate behavior openly will not get service.
Discrimination based on sexual orientation is not prohibited in Michigan, but some municipalities
have laws against it, according to the affiliate.
Grandville is not one of them.