I have a 1989 115 HP Mariner, had it serviced 2 years ago and have on not used it until this weekend, it starts with choke and stalls while idling, bumping the choke will keep it running, when at full throttle can only get approx 25 MPH versus 45 prior to tune up, if I keep bumping the choke at full throttle I can get it up to 35 MPH then it drops back to 25 MPH, I am definite it is a fuel problem but unsure where to start looking and route to go, do not have a manual or it either, any suggestions where to start, would fuel filter cause this? Any help would be greatly appreciated. Thank you inadvance