Coleman Powermate Powerwasher starts but then stalls?

I have a Coleman Powermate Powerwasher Model PW0912201 with the Honda GCV160 Engine. It starts fine but then shuts down immediately as if there is a shut off valve. the manual states there is a low oil shut off for the gas engine but that is not the condition,it has oil. I checked spark plug, carburetor and air filter and all appear fine. Even tried a new spark plug and draining and cleaning the carburetor float bowl to no avail. Gasoline is from last year but it has a stabilizer in it and have been using the same gas to run my mower for 5 weeks so I think it may have something to do with the pump. Is there something that the pump may have that could be causing it to shut down like that. Or what else do you think is wrong . Thanks.