Re: 1989 Johnson 8 hp loses prime and dies after 10 minutes
Could be a bad fuel pump, a bad fuel hose, an unvented tank, a sticking inlet valve on your carburetor or simply an air leak somewhere along your fuel lines, usually the connectors. 1st check look at all the connections for the fuel and make sure you are getting a good connection. Make sure the screws holding the fuel pump together and on the motor are all tight. I would then run the motor with the tank's cap off to eliminate an unvented gas tank. If you have another fuel hose, try that next. If those items are all working, then I would remove the fuel line from the carburetor and pull the starter cord of the motor (remove the plug boots if you don't want the motor to start) and see if fuel pumps out. If it does, then I would have to assume that the problem is in the carburetor's inlet valve that is stopping your fuel flow. To be sure, before you pull the carb you could try to jerryrig up a system that connects directly to the carb that allows gravity to feed the carburetor. If it doesn't work then, it has to be the carb. I suspect, however, that your problem is most likely before that.