Gas Stove/fireplace problem

Had to install a gas shutoff valve on the back of a direct-vent gas fireplace (free-standing ornamental stove) to meet code but now the main burner seems to be acting strange. Sometimes it goes out or doesn't want to light. The pilot stays lit. I am wondering if some dirt or rust might have been knocked loose and is now clogging the internal workings. I tried to clean out the pipe with a Q-tip as I was installing the valve but maybe there was still a bit of dirt left inside. I'm not sure how I might be able to blow any such dirt out with compressed air? Ideas?
Thanks
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

It occurred to me that the problem might be insufficient flow due to the added valve itself. I installed a 3/8" ball valve because the pipe on the back of the stove was 3/8" iron but what if the restriction of the valve causes insufficient flow? I guess I might be able to install a larger valve with with reducers. I will also check to see if running the furnace has any effect. This stove is on a separate line that branches off only a few feet from the gas meter.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.