115 4 stroke fuel issues

[Ashley smith]

I'm in the uk and have recently taken my boat out of winter storage, come to fire it up and it started easily as normal, idled for a while but then started to run lumpy like it was starving of fuel, I suspect low pressure fuel pump? Is there anyway of testing? If I take off outgoing pipe and crank over the engine should it push fuel out?
Any help appreciated, I missed a nice calm day last Sunday as the motor wouldn't fire 😢
Thanks
Ash

[Ashley smith]

Sorry should have mentioned not sure on year but itsfuel injected and low pressure pump is mechanical from camshaft
Thanks

[TownsendsFJR1300]

I'd drain (from the clear plastic hose) the VST and see if there's any fuel there and if so, the condition of of it. Catch it in a clean small container.

Maybe a couple of squeezes of the primer bulb as well..

Does the primer bulb stay firm after start up?



You also may want to check spark at all four plugs as well(should you have one mis-firing)

[Ashley smith]

How do I drain the vst? Where is it? Thanks

[Ashley smith]

I just want to know how to check the low pressure fuel pump nothing fancy, I'm not here to argue

[TownsendsFJR1300]

Take it to a experienced mechanic - not necessarily a dealer. VST has got to be done by a professional IMO. Here's a link of one of OUR MEMBERS-NOT a Yamaha mechanic servicing his VST(as an FYI): https://www.youtube.com/watch?v=fYo5...ature=youtu.be

Could be anything. Sounds like injectors to me. I'm not a mechanic, (obviously) but I use a very good one at $60 an hour. VST IS ONE SCREW TO DRAIN..

Poster above changed 1/2 dozen things on his own F150 before he discovered it was just spark plugs. Flat out Bull$hit. Read his link/post, if you don't believe me. Yes, please read, CS doesn't have a clue what he's talking about, except exhaust stacks..

http://www.yamahaoutboardparts.com/f...s-th26221.html

Poster above (myself) didn't CHANGE ANYTHING but the spark plugs and fuel. READ IT AGAIN SOLO but PAY ATTENTION.




Back to the thread, for the Op.

Part #14 is the DRAIN SCREW:

2006 and Later F115TXR Yamaha Outboard FUEL INJECTION PUMP Diagram and Parts

Also in the video posted above(different VST but same drain), it shows the drain screw as well.




.

[Ashley smith]

Does anyone know if I take off the output pipe from the low pressure lift pump if it should pump fuel out?

[pstephens46]

Solo does none of his own work.

Want to watch your low pressure pump operate?

Find the filter located on engine. Little clear bowl? Unscrew and dump out the contents. Screw it back on. Start engine and you will see it fill up.

[TownsendsFJR1300]

Plus 1 ^^^^

Right.

You want to chase around ghosts like he does?
http://www.yamahaoutboardparts.com/f...s-th26221.html

Your link doesn't WORK EITHER.

Try again or ask Floyd to help...