2005 F115 Yamaha won`t go past idle

[Iluvfishin]

4 stroke EFI. It has a bit of a struggle to start. A few cranks and then it grudgingly idles a little bit. If you give it any throttle it bogs and dies as if it is starved for gas/air. I had it at a Yammy dealer and he claims just the plugs were fouled and he didn`t have any so I took it home and put new plugs in and same thing. What can I all check? I`m not a boat expert but I`ve rebuilt many Honda ATV engines and work in a Diesel shop so I understand the basics. I bought the engine like this and the guy I bought it from said he was guessing computer might be bad. Is there a few things to rule out with these symptons before I start throwing parts at it?

 

[99yam40]

make sure cylinders are sealing properly and hook it up to a computer.

fuel rail pressure needs to be in spec. Too low or too high is bad
injectors can cause problems as you know if you work in diesel shop
they can be sent off to be tested and cleaned

 

[Iluvfishin]

I did a compression test and they were all within 5psi around the 130-135 mark. I wanted the dealer to put it on the computer but he wouldn't do it. Blamed the plugs. So he's not seeing it again. Next dealer is about 3 hours away. What is the fuel pressure supposed to be at?

 

[99yam40]

I am not sure, but the service manual for your motor will have the specs and info on testing most al systems

 

[Capt Ken]

Your fuel pressure is too low. Replace the HP pump in the VST tank. If you check the pressure with a gauge it should be around 35-40. You will probably find yours around 10

 

[Iluvfishin]

I did a bunch of digging today. On the fuel shrader valve I got about 40psi while cranking on a regular tire guage. Is that accurate enough? Is that pump simple to replace and cheap? Checked all the wires and had good spark. Took out all the plugs and cranked the engine in full throttle. Bottom 3 cylinders had mist coming out the plug hole but top had none. Took off all the injector wires and hooked the 2nd wire to the top one that didn`t spray any fuel.. No go. So obviously the injector is toast.