Outboard not running after 12 month not run

Barry Lee

New member
I have a 2015 70hp 4 stoke Yamaha outboard that has not been run for 12 months. It has always started first go in the past, even after a long period of inactivity but this time it will not run. It occasionally tries to kick over and on a couple of occasions after fiddling with the fuel system it has run for up to about 10 seconds, but then dies and will not restart. I assumed a fuel problem so have replaced the water separating filter on the boat and on the motor. I have been trying it from a fresh tank of fuel directly with a new fuel hose and primer bulb. I have taken the fuel injectors off and checked them off the motor and they are all working. (Have run carburettor cleaner through them with compressed air while activating them with a battery).
As it has run a number of times for a few seconds I assume the spark plugs, which have had little use, are ok and are sparking. I have however tried the old set from before the 100hr service with the same result. All the fuses I can find are ok and I have bought a new battery.
My thinking is that whatever runs the injectors is the problem as fuel does not seem to be getting past them. Spark plugs come out dry after attempting to start it and when injectors are removed, the fuel appears to be under pressure from the priming. Also seems to indicate the fuel pump is not the problem and seems to be working well when I checked it.
Looking for suggestions.
Living on the pension and with the increased living costs, the boat motor is unfortunately not a priority so need to fix it myself, if I can.