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Ok, so I just bought a 2005 Yamaha F115 on a 19' polar center console that I am having trouble with. It idles fine and revs fine out of the water but when I put her in the water she STRUGGLES to get on plane if ever. I have to place the trim tabs all the way down and it's still a gamble as to if she will get on plane. I thought it was severely over proper so I tried going down from a 13 x 17 ss to a 13x15 ss but it didn't change anything. Once it gets on plane it will top out at about 29mph and 5000-5100 RPM regardless of which prop I am using. I am thinking it may be a filter restriction as I don't know when any have been changed. I don't think it's much because she runs too good and smooth but it just doesn't seem to have the power there that it should. The engine only has 600 hrs so it's not a high time engine. I am a licensed aircraft mechanic and work on airplanes on the side for people so I am not scared of getting my hands dirty. I have built many outboards as well but these new FI motors are a different animal. Any help would be greatly appreciated.
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IMO it would not be overkill to dig down into the VST and check the screen on the high pressure pump.Originally posted by Av8erdunn View Post
Perhaps also pull the injectors and clean the "basket filters" on with some aerosol fuel cleaner -
How many filters does this thing have? I may be wrong in thinking filters but I am at a loss as to what else it could be.Comment
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monitoring fuel pressures will tell you if filters are the problem and whereComment
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Is there more than one port to check fuel pressure and would that tell me if the vct filter is plugged?Comment
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should be more than one pump to check the out put ofComment
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helpful to know that you have constant correct pressure on the fuel rail all the way to WOT - if not, could be restricted VST screen, or insufficient feed to VST
some models have a built in Schrader to connect a gauge, some you have to plumb in an adapter
don't know about yours....Comment
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you may have a "Racor style" canister filter between the fuel tank and the engine
definitely have a small "sediment bowl" type (with paper element) under the engine cowl
probably have a small "screen" in-line between diaphragm pump and VST
definitely a screen on the bottom of the high pressure pump inside the VST
and each injector has a screen in its inletComment
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I have ordered new filters and will tackle it this weekend. I also noticed that when I was pumping my primer bulb, it never really got hard. I went ahead and ordered a new primer bulb as well. Will probably change the fuel line from the tank to engine too!!!Comment
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I got home this afternoon and pulled the cowl just to look around. I pumped the bulb and wouldn't get hard. I pulled the filter / water separator on the back of the engine and it had a little water in the bottom but not too much. I pumped the bulb a couple times just for the heck of it then I put the filter back on. Pumped it again it got pretty hard. I am still going to replace all the filters and bulb but looking at the fuel line, it's going to be a bear to tackle. Might hold off on that. Just trying to give y'all as much info as I can. Thanks again for the help.Comment
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Originally posted by fairdeal View Post
I do have a sierra 10 micron between the tank and flow sensor (which doesn't work). Picking up a new one tomorrow. Now I need to find someone to send my injectors too.Comment
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Didn't someone have an issue on here with a faulty flow sensor awhile back? Causing running issues. Long thread?Comment
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That is an interesting possibility. I will search for the thread.
This sucks because living in Mobile AL the weather has been nice for the most part. I would rather be fishing than working on it.
Oh well, its still not as bad as the 31' Chaparral with twin IO Volvo Penta's I had.
ThanksLast edited by Av8erdunn; 02-09-2017, 08:41 AM.Comment
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Searched for the thread but couldn't find it.
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bulb not getting firm to me would mean sucking air on the suction side of bulb or fuel leaking out on the pressure sideComment
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