2009 40hp 4 cycle fuel injected - spark and fuel but will not start - only will with starting fluid

This is a 2009 40hp F40LA. I don't think this problem is specific to the model. So this is in MN where we have gas that has ethanol and causes many problems with engines. So this outboard probably sat for a year as is with no winterizing or draining gas. So it did start but ran poorly a month ago when I started to work on it and then finally failed to run unless a shot of starting fluid was sprayed in the intake. Here are steps taken: Drained fuel from tank. Replaced fuel separator filter that is between external fuel tank and outboard. Replace filter in water sensor. This is fuel injected so removed the VST and found it was filled with vanishing from sitting. Removed the VST body assembly and cleaned it out. Removed fuel pump from VST and cleaned it and filter. Same done for fuel pressure regulator. Put everything back together and it started 1 time and then would never fire. If again I sprayed starting fluid in the intake it would fire 1 time and then quit after burning up that. I pulled the injectors and the rail I cleaned the injectors externally and all looked good. I held the fuel rail as someone turned over the engine and there was a fairly good spray of fuel coming out. I reinstalled the rail and still would not start. If I took the rail off and sprayed some starting fluid in each port and replaced the injectors it would start for a brief second and then quit. How can I tell if it is a fuel pump problem or injector? I don't have a fuel gauge and I that is what I may need to get. But from the fuel I see coming out of the injectors during my test I can't understand why I don't see just a hint of it firing. Unless the pressure has to be so great to get inside chamber and that is what is wh. I really appreciate anything you can share regarding this problem. I don't have a trailer so trying to do this myself to save some $$$ as nothing is cheap. Thanks!

isc valve may be stuck closed, it is part of the throttle & body easily tested with ydis. Does the engine stay running with a little throttle?
To check the fuel pressure you need an adapter that clips onto the top of the rail.

I can check the isc but don't have access to test with ydis. Engine will not stay running with applying a little throttle. There is a Schrader valve on the vst that I can connect a pressure gauge to and will be doing that today. It is almost like the injectors are not spraying enough or far enough into the intake for it to fire. As I indicated when I spray starting fluid in the injector ports and quickly put the injectors and fuel rail back in place it will fire up on that instantly but then die again.

The schrader valve on top of the vst is a vent used when draining the vst. me thinks there wont be pressure there :rolleyes:

fishingoats was correct, there was no pressure on that Schrader valve. In fact, if I took the valve out and attempted to start the engine, no gas even came out of that location so there is no pressure in the vst tank but just the actual line itself that heads to the injector rail. So I have no way of testing fuel pressure unless I get that clip that attaches to the rail. When I hold the fuel injector rail and have someone crank over the engine, there is a spray that goes almost 2ft so I have to believe that is enough pressure. The only thing I can think of is that the fuel pump is still not strong enough or screen is blocked preventing it from getting enough fuel to the injectors themselves.

What is the serial number of the motor? Early F40LA's had a bulletin issue for VST fuel pumps. Did you have the bulletin work done?

So the sticker says F40LA and then next line is 6BG L 1008188 F . No I was not aware of a VST fuel pump bulletin. I'm not sure if the number I provided is the s/n or not. It is up at a cabin so not easy to work on or get this information right away. Appreciate feedback and I can call dealer too and see if there is a bulletin related to this.

Your motor has had the modification performed.

I see that the warranty just ran out last month. Why not take the motor to a dealer and have him ask Yamaha for some goodwill assistance getting the problem fixed? Depending upon the problem, and the fact that your warranty just expired, Yamaha might be willing to help you.

If you pulled the fuel rail with the injectors still plugged into it and turned it over and saw fuel "spraying" (not squirting) from all injectors this doesn't seem to be a fuel problem. The fuel and air mix is injected/introduced on the intake stroke, then it is compressed on compression stroke, then fired on the combustion stroke and exhausted on the exhause stroke. Each "stroke" represents travel of the cylinder be it up or down. On the intake stroke, there is no compression so as long as you have a good SPRAY from the injectors I don't see a fuel pump problem in your case. However, you could have a leaking injector problem. In other words... your injectors are always under pressure but if they are leaking regardless of when they get the signal to spray they could be spraying fuel all the time creating an over-rich situation. Before you start chasing ghosts, I'd send your injectors out for testing and cleaning. I send mine to Dale who runs fuelinjectorman.com in FL. Cheap testing, cleaning, etc. You can clean them youself and they may spray fine but you can't tell if they fully shut off when they are supposed to. You'll see this problem from leaking injectors.

Quick check... Hook up your injectors, fuel rail. etc and put all in working order... Crank it over several times. No start... pull your plugs and see if they may be wet or smell of raw fuel.