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Losing power


General disarray

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Ok guys, so I got everything accomplished (Vst, mid pressure filter, and 2 mystery filters in my pump) and threw it on YDC. System shows all 6 cylinders firing (when in gear) 1,4,5,6 firing when in neutral and a low side pressure of 4.8 and high side pressure of 675 (within spec). Hopefully this fixed my issue - I am going to run her tomorrow morning and see if it did. 

For those of you using YDC - how do you get the 15 minute history? Is there anything else I should be looking at? I have no diagnostic codes and I was using the engine monitor. 

For those and everyone else - I have attached the snap shot of it running at idle as well as this photo of my VST filter. 
 

Screen Shot 2017-12-30 at 3.48.56 PM.png

Screen Shot 2017-12-30 at 3.48.39 PM.png

IMG_5054.jpg

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OK so so results.

Was still only able to hit 5k and 49mph before it blew out. Good news is YDC shows all cylinders firing. I did manage to find another issue but I don't know that it would effect my max RPM. To start his is a shortened read out as I cam through the RPMS:


80-screen_shot_2017_12_31_at_4_22_27_pm_


What I found when I removed the cowling and heard a pssst, psst, psst, psst sound was one of the low pressure pumps he did clearly had the gasket installed incorrectly. See photo:


80-img_5066_4ea9c2d325e661029ff0344f9a89

I guess question is:

1) Could this gasket be causing my issue - It appears as though my fuel pressures are still in spec so I doubt it.

2) There is definitely oil getting all over around this pump. I can't find an oil leak and it didn't do this before the work so I am thinking its bleeding from the case where the gasket isn't right?

3) Based on the data and what you guys know where else could my issue be if its not that low pressure pump? Would it show cylinder firing IF an injector was plugged or is that simply a spark reading? I did notice the throttle position doesn't get past 73.5 degrees (YDC parameters are 0-90) is that where it should be or the full 90?

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  • 3 years later...


I have a 2006 Yamaha 225 HPDI that looses and gains power while I throttle it down. It idles fine, I replaced the paper filter in the plastic separator also replaced the metal filter above the electric fuel pump housing and also replaced all 6 plugs. I had my son continuously compress the primer bulb when I throttled her down again and the boat seemed to run good. We noticed what looked like a little gas in the water when we put her in the lake and also my son noticed it last week, this was before I replaced those 2 filters. 

Please someone help me. I do not want to blow up my engine. All the plugs were oil fouled but this was because the plastic retainer on the oil pump rod broke, I replaced that a month ago.

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