I use Lucas fuel cleaner and it works great in cleaning CMAX fuel lines and injectors. I use 1/2 bottle per tank-full once every month or two: https://www.amazon.com/Lucas-Oil-LUC10020-Ounce-Treatment/dp/B0006305RY/ref=sr_1_2?crid=1BS63B59JNO1X&dchild=1&keywords=Lucas+Oil+LUC10020+Fuel+Treatment+-+5.25+Oz%2C+Multi-Colored&qid=1635463285&sprefix=lucas+oil+luc10020+fuel+treatment+-+5.25+oz%2C+multi-colored%2Caps%2C68&sr=8-2
There are also larger bottles available (I keep and re-fill the small bottle because the spout on that bottle works well in CMAX fuel inlet)