Honda BF15 fuel pump

Hi all; I have a 1999 BF15AX, manual choke, electric start & tiller steer, that I think I have diagnosed with a weak fuel pump but want to confirm my diagnosis. Fault - it starts fine with normal choke and the fuel bulb primed, but runs the small in-line filter dry at an idle after about 30 seconds or so dies, if the bulb is pumped again then it will continue to run fine. This happens the same at higher revs, just a bit quicker. I have removed the fuel tank and put it above the motor and removed all the joins etc between the fuel tank and the fuel pump (so it gravity feeds) and it runs indefinitely. At the same time, I connected the fuel pump up to a glass jar (in and out with only about 6 inches of hose) and it seemed to pump fine. I then put the boat back on the water with the fuel tank still fixed up hard with no joins but down in the bottom of the boat and it would run for about a minute at low revs, but only about 20 seconds at full revs, again if I pumped the primer bulb it would continue to run. I then put the fuel tank up on the seat with me, it wasn't above the motor, but only about 6 inches below the carby level, it would then run at all rev ranges without stopping. So I have confirmed that the fuel pump is pumping, with no real load on it, but also confirmed that the carby/electrical (I hope everything else) is working fine. So this leaves me with the fuel pump, I don't have much experience with petrol motors, I have had diesels my whole life, so want to double check before I pay $150 for a new fuel pump. The fuel pump is the simple diaphragm type. Thanks for your help. (Sorry not to have paragraphs, but I can't seem to get the enter button to work, to allow me to do so) Brett

Take that simple pump apart first, might be as simple as a bit of dirt on a check valve.

Thanks for that mate, but already done. Cleaned it out with carby cleaner, appeared to be fine, no obvious contamination and no obvious tears/holes/leaks. Thanks Brett

Sorry , that detail appeares to be missing in post #1.

Sorry about the lack of some smaller details, I was trying to keep that first post down to a manageable size. Apart from cleaning the fuel pump, I have also pulled the carby apart a couple of times and cleaned it, I have cleaned and checked the gap on the plugs and checked all electrical connections I can find. I think it has to be the pump, but at the same time, I thought that a diaphragm pump either worked or it didn't. I didn't think that it could be "weak". Thanks Brett

Hi,
I have the same problem.
Did you ever find out the cause and fix it?
Thnx,
Mark