# 2007 Yamaha F150 4-stroke giving me fits!!! HELP!!



## JMACHALA (Apr 16, 2011)

I am at my wits end here! I just bought a 2007 Shearwater with a Yamaha150 4 stroke on it. During the test drive the boat ran well and did not see any real issues with the boat. The guy that I bought it from had changed the fuel filter just previous to me acquiring the boat. When I got the boat, the fuel/ water separator had not been changed out in quite some time so I did that and it was basically half-gas/ half-water. 
I took the boat out and ran it and was getting out of the hole really well, and topping out at about 5400 RPMs. It ran great for about an hour and a half..... on the way in,when it didn't die when I hammered it, it got super sluggish would not get about 3000 RPMs on take off and was almost impossible to get on plane and wouldn't get above 4100 RPMS. I thought maybe the fuel water separator had pulled some more water out of the fuel, no water in FWS so i drained off about 15 gallons, and the gas that I was getting from the boat looked absolutely perfect so I did not drain off anymore....

I took the boat into Texas Marine and they checked it out, the boat diagnostically is an absolutely perfect shape. They are having the same issues that I was and cannot figure out what the deal is, and I was told they have a call into Yamaha for help, seems weird that their Tech can't diagnose the problem, but maybe he wanted to consult an expert?

I have every maintenance record and every receipt from this boat since day one that is been purchased down to the batteries. It has been serviced religiously. 

Does anyone have a clue what it may be, bad gas? Clogged injector? I am absolutely frustrated with a brand-new boat (to me) that I can't use!

I appreciate any help and or advice that you may have to offer.


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## EvansMarine (Jun 7, 2010)

VST and injector screens need to be cleaned if no code for sensors. Also check fuel lines, anti syphon valve on tank and fuel primer bulb. It is a restriction in fuel flow!


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## cadjockey (Jul 30, 2009)

Could be clogged injectors or VST tank filter. Injectors are the easy one. These people will clean and flow test your injectors in the Hou area: http://www.injectorrx.com/ Pull the injectors yourself, it's easy. I had a similar issue with a pair of F150s and injector cleaning solved it. The VST tank filter is a little more involved...and there are at least two other little fuel filters under the cowling.


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## Sonnysmarine (Mar 18, 2007)

We just had the same deal would run, then start losing, rpms-power, first run on portable tank and check if same them in the engine if runs , the anit sipon valve, might be stopped up or not flowing fuel proper, 
If no change then most likely the VST tank filter and Or Dirty injectors, Ours was both, filter was dirty and ran it again better but lost power, sent injectors out and got them cleaned , ran and tested 6000 rpms. Dang ethanol is causing all kind of problems , Keep the fuel filters changed often, All of them, cheaper than the Shops bill.


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## JMACHALA (Apr 16, 2011)

Thank you very much for the replies, I can only believe that it is all of you said ,a fuel issue. I am certainly not a mechanic but it would seem to me that a Yamaha authorized dealer would be able to fix this problem without too much of an issue. 

Does changing the inner fuel filters, besides the cup filter on the front of the motor require a lot of disassembly? I don't really have a desire to go into tearing into my engine but if it is something simply done I have a decent amount of mechanical ability, but don't want to get in over my head! LOL! 

It stinks to have to do this with less than four hours on the motor since I got it, but it appears that ethanol has played a major Part in making sure that the mechanics keep a fat wallet. Don't get me wrong, I certainly appreciate them, it is just super frustrating.


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## Newbomb Turk (Sep 16, 2005)

You said the fuel/water separator was 50/50? I'd start there. Drain your tank, flush your fuel lines to make sure you have clean fuel to the motor then start over...


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## LouieB (Jun 7, 2005)

I'd go straight to the fuel dicombobbulator and the flux capacitor.
Good chance those are anti-fouled and running on 1/3 power.


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## baynick (Oct 14, 2009)

*07 4 stroke yamaha*

JM. 
Mr Evans is correct. The VST changed and the injector screens must be cleaned. Ethanol is the problem, so from now on treat your fuel with a Stabil type product and Yamaha Ring Free. This may not eliminate the fuel problems but will reduce them. Biggest problem is that more than likely in 4-5 hours more use, you may lose your fuel pump. I hope you are in warranty. They tell me that the fuel pump had to work too hard to force fuel thru the injectors and burned up, just quit running when on cruising speed of about 4000 rpm.

On another note, they are a great motor, dependable and very fuel efficient, they just do not like ethanol or the effects produced by ethanol.

baynick


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## JMACHALA (Apr 16, 2011)

Don't say fuel pump! I have used Ring free and Stabil since I got it......"Hopefully" Since I did get ito the shop right after I started experiencing a problem hopefully that would be some decent preventative from further damage


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## EvansMarine (Jun 7, 2010)

You might want to call the service center and let them know what they need to check out, since they dont seem to know what they are looking for!


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## JMACHALA (Apr 16, 2011)

I am....and can you PM me a contact number please.


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## paragod (Aug 25, 2006)

EvansMarine said:


> VST and injector screens need to be cleaned if no code for sensors. Also check fuel lines, anti syphon valve on tank and fuel primer bulb. It is a restriction in fuel flow!


I would say Bryan is 100% correct I have had 4 4 strokes in the last month all with Yamahas and all had stopped up injectors I sent them out had them serviced and changed all filters from tank back including the VST tank all have run like new all had 20-30 % spray on the bottom injector on the fuel rails.


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## paragod (Aug 25, 2006)

forgot check fuel psi on fuel rail also


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## thehastenman (Nov 14, 2011)

Hey dude I was sitting at work and thinking about the Shearwater and how good of a boat it was and why i sold it! :headknock So I searched Shearwater and your post is the first one that comes up! Man Im sorry to hear that about the boat! It never did that to me, it did sputter a couple times which sparked me to change the filter on the motor. ( Not sure why I didnt change the other one) My buddy has a F150 on his boat and he just emailed me the other day with the same problem and asked me if I ever had that. Anyway he went through the same diagnosing bs and turns out it was just the throttle cable. There are some catches that hold down the linkage( under the cowling) and they simply popped out and the cable wasnt engaing the throttle all the way. He popped them back in and it was good to go. Give it a look before the shop charges you out the *** per hour. 

Oh yeah BTW im still waiting on that striper fishing invite! ha


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