by Old Dude » Sun Apr 12, 2015 5:23 pm
Welcome to CRFsOnly, By "it's spurts gas backwards out of the carburetor" do you mean that it runs out the carb overflow tube? If so you may have broken some crud loose in the carb and plugged up the jets. Especially if the bike has set for a while. If it hasn't been rejetted, now would be the time to do that. While you are at it, take the 'snorkle' out of the top of the airbox. If it has been rejetted, remove them and clean them thoroughly and clean the carb with carb cleaner. Check the float valve for wear and proper float setting. New jets are inexpensive. A Honda Service Manual is invaluable for the carb clean and adjusting process. Re jetting specs can be found right here using the search process. I'm primarily a 230 guy so can't speak to the specifics of the 150's jetting without doing a google search or a search here for you. BTW the OEM float bowl screws are very soft so be sure you use the proper screw driver for their removal. Oh, and for ease of fine tuning, an extended fuel screw available here is a must.
O.D.