2005 4stroke yamaha fuel issues

[yaksterr]

225hp yamaha fresh out of the mechanics shop for replacing the lp fuel pump, vst, filters ect. The original problem was low pressure pump kept blowing fuses (for the third time in the shop). After all parts replaced drove 4hrs back to Corpus and hauled it back home. Put in the water the very next day only to have the thing not rev above 3200rpm. Sounds like it is starving for fuel because once you get past 3/4 throttle the hp drops off and starts to decelerate. Checked all fuel lines for kinks and contacted the worthless mech we used. Still no response from him so here I am trying to figure this thing out for my dad and any help would be greatly appreciated.

[yaksterr]

Don't everyone jump in at once.

[exttrimmer]

Dude
its a friday, last minute and your mad because no one answered you. Sounds like the boat has been out of commission for a while. Relax the guys here will help. Provde as much info as possible, whats been done to correct prob. etc. The guys here will help if they can

[99yam40]

monitor the fuel pressures to see what is going on.
The are no crystal balls for us to look into, so you will have to do some testing or take it back to the shop so they can do some testing

[mitch]

you need to see what the high pressure fuel pressure is at key on and running .

did they clean the injector filters as well ? was there water in your fuel ? is that why they fitted a water trap .

you can buy a fuel pressure gauge for about $50

[Papa Basscat]

Borrow or buy a fuel can and run the fuel line directly to engine and test run it. This will isolate the problem between the boat and engine. Ethanol fuel will eat up a fuel line from the inside out and it will collapse when the pump is trying to pull fuel under a load. It will run at low rpm but as soon as you put a load on it it collapses. I see it all the time at my work. Try it and see how that works then we will move on to the next possibility.

[Papa Basscat]

Another good web site to get help on is bass boat central.

[RangerBoy]

your 2005 is also the year before they changed the fuel lines to tolerate ethanol fuel blends. If its a grey line with a red stripe, you have an issue with the hose feeding broken down hose goo into your engine.. I've heard of people having problems all the way to the VST filter because of this. Papa Basscat is probably right, if your fuel line is such, its breaking down and probably collapsing as well.

[yaksterr]

Ok, the fuel pressure key on is 42psi initially then it holds at 38psi running. Checked the coil packs for resistance and all were within spec. Checked compression and all were 160psi or greater. However I did come across something I beleive to be a problem and would like some fedback. On the air intake box there is a one way check valve that comes off the back of the air box and is the vacuum supply for the vapor recovery system. It allows intake vacuum at the valve and in case of engine backfire it checks toward the fuel system. As I tried to blow through both ends of this one way check valve and could get very little air movement in both directions. If this vavle is stuck closed its not allowing vacuum to pull the vapors off the top of the VST right? Oh yeah and that little valve is $205! part # 69J-14989-00-00 Sorry for being short and testy guys, just stressed out over this problem

[99yam40]

Is it holding 38 even when the rpms are restricted to 3200?

[yaksterr]

Yes it holds at 38psi while running

[99yam40]

I did not ask about just running,
I asked about while the problem is happening, limited RPMs.

Something has to be changing that is limiting the RPM, if fuel pressure is not the problem, the timing or loosing spark to one or more cylinders maybe it.

Or like they have already stated the fuel injectors

[yaksterr]

Ok so we found out what the problem was. Finally had a chance to put the boat in the water for a test run and it was doing the same thing. It would get to 4200rpm and fall off. So we stopped and I installed the fuel presusure gauge and took off again and watched as the fuel pressure dramatically fall off to around 25psi. Priced out a new hp fuel pump at around $800! Just glade we are on the right track. Thanks for all the input fellas' have a great holiday weekend!

[herb.wilson@uno.edu]

Could be the fuel pressure regulator on top of the rail. Not a mechanic but jut a thought.

[99yam40]

partial blockage/restriction some where.
filters, screens, pick up tube, connectors, primer bulb, check valve