Yammy F15 Intermittent Problem

Bought a 2005 F15 electric start Yamaha last October. Ran it 3 times in November and December, and twice in January with no problems. Then later in January, cruising along at full throttle in the harbor on Lake MI later in january, the thing just died. Started right up, and ran fine rest of that trip. On several subsequent outings, it’s happened a few times at full and half throttle…will die like the kill switch has been activated, but then fires right up and runs fine for a while. Does it intermittently on every outing now. I haven’t run on low RPM for any extended time, so don’t know if it would happen then, too.
So far, have added Sea Foam to the gas, and have held the primer bulb to pump it up the second I hear it beginning to die. Tried that yesterday, and only one of four times was I able to keep it going by pumping the primer bulb.
Bought two new plugs, but did not change them yet. Thinking that if one went intermittently bad, the motor would still run, albeit roughly.
So still not sure if fuel problem, or electrical problem. Thinking it might be faulty kill switch, but haven’t dug into that yet.
Any ideas?

I had the same thing happen to my 175 Merc. Ended up being a faulty primer bulb in the fuel line.

Sounds like an electrical issues. I would check all electrical connections to and from the motor. Could also be a faulty tether switch. Does the 15 have an engine control unit? If so that’s were I would start looking at connections. Hope this helps electrical issues can be difficult to figure out.

Good luck, Jeff

If you have the plugs, put them in and eliminate one possibility.
You put in sea foam, but is the gas fresh?
Have you cleaned or changed any fuel filters?

Superdo. Did your motor die instantly like someone turned a switch, or did it sputter a bit before dieing? Mine goes out fast.

The latest in my troubleshooting efforts on the intermittent problem.
Replaced both spark plugs during the week, and checked all the harness electrical connections to make sure they were snug. had the boat out yesterday, and same thing. Jiggled the kill switch button and tether to try to make it die, and would keep running. Also, tried pumping the fuel ball the second I heard it start to die, and no help.
I do have a spare Yamaha bulb from troubleshooting my other Yammy two years agao(that turned out to be a fuel pump), so going to swap them out just to make sure it’s not the bulb.
After that….probably going to have to wait it out, till s whatever it is goes all the way.