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rbrentp · 31-12-2017, 08:42

I am stumped.

25 HP 4 stroke Yamaha outboard 2010. Carb is clean as a whistle, all channels blown out.

Starts right up, idles great, goes into gear and accelerates to about 2200 rpm. Then dies. No sputters, no coughs. 2200 runs, 2300 dies.

Jets are clear. Fuel Starvation? Never seen that cause an engine to shut down without a stutter of some kind.
Yamaha says there are no electronics that could cause it.

Any ideas would be very helpful.

Brent
Snowgoose - Catatonic

NoTies · 31-12-2017, 16:34

Try pumping the primer bulb after starting and see if it keeps running. Sounds like it could be a fuel pump problem.

rbrentp · 02-01-2018, 10:26

I will try that. It can't hurt. I can't imagine how a fuel pump would stop at 2300 but that doesn't mean it can't.
Thanks

NoTies · 02-01-2018, 15:11

Not stop, just unable to deliver enough fuel, the level in the float bowl drops below the jets and the engine stops.

susswein · 02-01-2018, 15:32

low oil level auto shutoff?

flyingfin · 02-01-2018, 17:53

NoTies is correct, run the boat again and when the problem begins try pumping the primer bulb. If problem goes away while pumping, you could have an air leak in the fuel line or a clogged fuel filter. If engine dies while pumping, you probably have an electrical issue, and need to check plugs, then stator

Frankly · 02-01-2018, 18:30

I went through an intermitent running problem with my 5 hp Nissan. Turned out I had switched the deadman key between my 115 Yamaha and the Nissan and they were slightly different thickness. Was about to replace the switch on the Nissan when I discovered the real issue. Long shot, but might disconnect the switch on the Yamama see if it helps.