1988 Mercury 115 hp want keep running unless you pump bubble. There seems to be no leaks (sucking air) so is this fuel pump?? I have replace bubble and checked it for leaks.
It sounds very much like a bad fuel pump. You can get a rebuild kit for that motor for a few dollars. Take the serial number to the Merc Dealer to get the correct one. Aos get a service manual to guide you on the repair. It is very easy, BTW.
Boat would run at 1/2 speed until I squeezed primer ball. Thought it was ball or fuel pump. Ended up being clogged jets on one of the lower two carbs. Soaked all carbs in 1 gal of chem dip and blew off w/ compressed air. Problem solved. You may try this or you may need new fuel pump. I had replaced mine a few yrs previously so I did not suspect it was the pump for me. Good luck!
