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  1. #1

    Default Yamaha 2005 150 hp 4 stroke problems

    hi,
    i'm new to this forum but hopefully someone can help me with my problem. i have a 2005 20'6" sea pro with a yamaha 150 4 stroke. it has been sitting with a full tank of gas since august and i took it out for the first time yesterday. it started off slow and would only get up to about 3500 rpms and 20 mph, then after about 20 minutes of running it wouldnt get above 3000 rpms and 10 mph and refused to plane out. i was told to try emptying out the fuel filter and the fuel/water seperator because water would mix in the the fuel from sitting so long, and that didnt seem to help after doing so 3 times. my offshore season is right around the corner and i need to get this problem fixed so any help would be greatly appreciated!!!

  2. #2
    Join Date
    Jun 2009
    Location
    , Florida, USA
    Posts
    91

    Default Re: Yamaha 2005 150 hp 4 stroke problems

    do you run fuel with Ethanol in it? Did you add fuel stabilizer before lay up? Did you winterize the motor before lay up?

  3. #3
    Join Date
    Sep 2006
    Location
    SF BAY AREA, CALI, USA
    Posts
    8,641

    Default Re: Yamaha 2005 150 hp 4 stroke problems

    you have old fuel
    HUMAN BUILT = HUMAN FIXED

    CERTIFIED MARINE TECHNICIAN

    WWW.SWITCHBAIT.COM

  4. #4

    Default Re: Yamaha 2005 150 hp 4 stroke problems

    everytime we went out we would refill the boat, if we used 40 gallons we would put the 40 gallons right back in when we returned to the dock, and i used startron to help with the ethonal everytime we added fuel and it worked well until now, and if the fuel is the problem if i were to drain out the 75 gallons and start over would that fix the problem? or do i need to have my fuel injectors rebuilt as well?

  5. #5
    Join Date
    Sep 2010
    Location
    Jersey Shore
    Posts
    3,150

    Default Re: Yamaha 2005 150 hp 4 stroke problems

    Quote Originally Posted by csutton View Post
    hi,
    i'm new to this forum but hopefully someone can help me with my problem. i have a 2005 20'6" sea pro with a yamaha 150 4 stroke. it has been sitting with a full tank of gas since august and i took it out for the first time yesterday. it started off slow and would only get up to about 3500 rpms and 20 mph, then after about 20 minutes of running it wouldnt get above 3000 rpms and 10 mph and refused to plane out. i was told to try emptying out the fuel filter and the fuel/water seperator because water would mix in the the fuel from sitting so long, and that didnt seem to help after doing so 3 times. my offshore season is right around the corner and i need to get this problem fixed so any help would be greatly appreciated!!!
    You cannot empty out these filters and reinstall them. They need to be replaced. Replace them and try again.

  6. #6

    Default Re: Yamaha 2005 150 hp 4 stroke problems

    I have the same setup (Seapro & 150hp 4 stroke) with the same problems. Did you every resolve your problems?? I am getting ready to dump all my fuel and start over. Have a good bit of water in the seperator every time a change it each month now.

  7. #7
    Join Date
    Jun 2011
    Posts
    107

    Default Re: Yamaha 2005 150 hp 4 stroke problems

    Just an idea here: it would be much faster and cheaper to get a small gas tank and put fresh fuel in it and run it.

  8. #8

    Default Re: Yamaha 2005 150 hp 4 stroke problems

    Thanks Vinh, last weekend I cleaned the injectors and did just that. I ran 6 gallons of fresh premium fuel in a clean tank. I gained some rpm but never ran like she should. I have a fuel filter/separator as well as a glass inline filter. The separator collects a great deal of water. The inline filter keeps collecting small black specks. I don't know if it is dirt, or pieces of the fuel line. I'm afraid the ethanol might have destroyed the fuel line. I have ordered new injectors and going to dump fuel and replace the fuel line. Also clean the 3 filters on the engine; bowl, inline & fuel pump filter.

  9. #9
    Join Date
    Jan 2009
    Location
    Posts
    63

    Default Re: Yamaha 2005 150 hp 4 stroke problems

    I don't think you need new injectors, just have the injectors cleaned professionally.

    If you do have have a problem with a fuel line or part of the fuel system disintegrating it will come back to haunt you even if you clean all your filters. I had a problem with a pair of 115s and ended up changing out the tanks, after about 4 complete filter changes at close to a grand in labor and parts each time. Sounds like you have a 75 gallon tank. If it's accessible I'd drain it and clean it and then replace all the fuel lines going to the motors. Is the tank plastic or aluminum? We had aluminum and they were corroding.

    As for the motor I have the same model and year and I'd first make sure your fuel separator filter is at least the 10 micron yamaha filter (I actually went to the 2 micron racors on my f115s in Florida, but use the 10 micron Yamaha for the f150 as it is in Minnesota)

    Then change the filters on the motor (filter in bowl, filter on top of VST, and filter on pump in VST). And then have the injectors rebuilt. It costs about $20-25 per injector and they will be good as new. (Many places to get it done, injectorman.com is one).

    In the end there are filters everywhere on the motor, and if you give them a reason to plug up they will.

    Good luck - Dan

  10. #10

    Default Re: Yamaha 2005 150 hp 4 stroke problems

    Thanks Dan,

    I am onboard with what you are saying. I have a 75 gallon aluminum tank. I found a recycle center that will take my fuel. I have all my new filters ready to change out. I use a 10 micron fuel/water separator. Unfortunately I have already ordered the injectors. Bottom line: change all filters and injectors. Dumping all fuel and cleaning the tank. Replacing fuel lines from the tank to filters and engine. If that doesn’t work I'm buy a canoe.

  11. #11
    Join Date
    Sep 2010
    Location
    Jersey Shore
    Posts
    3,150

    Default Re: Yamaha 2005 150 hp 4 stroke problems

    http://fuelinjectorman.com/ I have a set to send out. Thanks for the contact.
    Chris
    Dockside Marine Services
    Jersey Shore.
    Let the insanity begin.

  12. #12
    Join Date
    Jan 2009
    Location
    Posts
    63

    Default Re: Yamaha 2005 150 hp 4 stroke problems

    As you have the new injectors coming, send the old ones in for cleaning and have them available as a spare set. Also it's been covered before, but I'd get a fuel pressure gauge that you can attach to the schrader valve on the fuel rail. I called this site and they don't carry a pressure gauge for a Yamaha, so I'd call Andy at SIM Yamaha (simyamaha.com) and have him send you one. Andy is very knowledgable on filters and Yamaha 4 strokes in general. You should have 40 psi of pressure and if it falls off when engine rpms drop you have a clogged VST filter. If pressure stays high when problems present you have plugged injectors.

    Also if you're interested in how the VST is changed on an f150 with some nice pictures I've attached a link below.

    http://www.thehulltruth.com/shipyard...placement.html

  13. #13

    Default Re: Yamaha 2005 150 hp 4 stroke problems

    Dan,

    Thanks a million on the link. Just what I needed to complete my project this weekend. I've got everything to change the 3 filters on the engine, I have injectors coming this week, will dump the fuel in the tank and replace the fuel line. I ran the boat yesterday and could only get 3200 rpm out of her. If I pump the throttle, it would pick up rpm and speed then bleed back off to 3200 rpm. Hopefully by Sunday she should be back to 6000.

    Thanks again for the help!

    Kelly

  14. #14
    Join Date
    Jan 2009
    Location
    Posts
    63

    Default Re: Yamaha 2005 150 hp 4 stroke problems

    One last comment before you dive in........the bowl on the front of the motor with a red disc inside is meant to show if you have water in your fuel. The disc will float up with water and remain at the bottom in gas. Is that red disc up or down on yours? Anytime someone has a water in fuel problem, that bowl should be removed and gas inside should be dumped. Andy at simyamaha told me that if there is a fuel separating filter between the tank and engine he removes that filter as it is meant to be a fuel separating filter too....(I left mine on).....albeit nowhere near as good as the large cartridge filters. There is also a drain screw on the bottom of the VST which is connected to a plastic hose that allows you to drain the fuel in the VST.

    From my experience the VST filter on the f150 is much larger than on the f115s, where I had all of my plugging trouble, and I would think less prone to plugging up. I also think it's a good idea to pour the fuel from your separator into a clear container to get a look at what's in it when you change it out.

    Good luck

  15. #15

    Default Re: Yamaha 2005 150 hp 4 stroke problems

    I'm glad you explained the red disc; I wondered what function it had. Off hand I can't recall its current location. I believe I will leave the bowl filter in the system as well. Thanks for the pointer on the drain screw at the bottom of the VST. I poured the fuel out of the filter/separator into a pickle jar a few weeks ago and had 3/4 inch of brown water in the bottom of the jar. Bad thing is the filter was only in service a few weeks. It will be interesting to see what's in the tank. I wonder if I skim off the top of the tank I could burn that fuel in the lawnmowers?

    Thanks again,

    Kelly

  16. #16
    Join Date
    Jan 2009
    Location
    Posts
    63

    Default Re: Yamaha 2005 150 hp 4 stroke problems

    To drain the VST there is also a schrader valve on top with a little rubber plug you remove to get at. Once you open the drain screw on the bottom of the VST, pushing in the pin on the schrader will allow air into the VST and thus let the gas drain out (otherwise vacuum will hold gas in the VST bowl). You'll see all of that when you get the VST off.

    As for the gas you remove we burned most of ours in an old cadillac, I just tried to make sure it was pretty clean. You're right in that all the bad stuff is at the bottom of the tank.

  17. #17

    Default Re: Yamaha 2005 150 hp 4 stroke problems

    Saturday I replaced all three filters on the engine, changed the injectors and dumped the fuel. Filled up with non ethanol gas. Put her back in the water and she ran like a champ. I've put about three hours on the engine and rpms have not waviered. I am going to send my other injectors off for cleaning and have for spares. Thanks for the help.

  18. #18
    Join Date
    Jan 2009
    Location
    Posts
    63

    Default Re: Yamaha 2005 150 hp 4 stroke problems

    Glad things worked out............as common as these fuel problems have become with the Yamaha's it's nice to be able to fix them ourselves.

  19. #19
    Join Date
    Sep 2011
    Location
    Brick, NJ
    Posts
    1

    Default Re: Yamaha 2005 150 hp 4 stroke problems

    Had same problem when I bought my boat. Tanks full of old ethanol gas. Problem is that normal regular gas is described as 87 octane. My belief is that fresh ethanol is about 85, quickly reducing as it gets older and absorbs condensate. I resolved problem by adding octane booster... came right up to plane. Used up gas.... refilled, stabilize. No matter what you hear from motor manufacturer... store boat with full tank, allowing little potential of diluting with condensate over the winter. I'm not impressed with the advice that's given today. Pick some "old timers" brains! There's nothing like experience mixed in with common sense.

  20. #20

    Default Re: Yamaha 2005 150 hp 4 stroke problems

    Interesting, I am going through the same exact issues with my 2004 SeaPro 206 and F150. I have tried everything with the gas lines and filters, no luck. Next step will be the fuel injectors and possibly the VST screens. I am thinking that maybe this is a an issue with E10 and the stock fuel tank vent placement, on side of hull. I have heard of other boats having issues with water getting into fuel tanks via the fuel fill vent... add the E10 water attraction properties to the mix...and now we have a problem.

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