yamaha f40 problems

Discussion in 'Outboard Maintenance' started by jlanzone, Dec 14, 2008.

  1. jlanzone

    jlanzone Well-Known Member

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    I have a Maverick HPX 15 with a Yamaha F40. It is a 2005 and just went onto extended warranty. I have had it for one year and this will be the second major carb job in the last nine months, each about $800. Neither was covered under warranty because they were felt to be fuel related issues. I usually post on the Maverick Forum and there is slot of grumbling about problems. Is anyone here having problems with the F40 in terms of the carb crapping out and the boat stalling?  Does anyone  have an F40A fuel injected engine? Any problems? Since I might be repowering, does anyone have a Honda 40 or 50? Yamaha has kind of ticked me off.
     
  2. iMacattack

    iMacattack busy, too busy

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    Welcome, Sam Adams Winter Lager Please.. ;)

    I run a 2008 16' Waterman with a F40 Here 35 hours and it's had three card jobs. Twice cleaned and the last time replaced. I'm well versed in the problem. Yes it is a fuel problem. You have E10 in your tank? That is the most likely cause.

    Here is the scoop I got right from the horses mouth, Yamaha.

    1. EFI 40's are not in the market yet... SOON they claim. Last I heard Mid February. But that could have changed. Yamaha claim that the new EFI motors will not be as susceptible to the E10 issue as the carb F40's are.
    2. The most likely problem is the idle speed jet is getting clogged. Is you problem bad idle, won't start, bogs when trying to throttle up?
    3. From what I have been told the problem is that when E-10 fuel when it sits for a while, as we all know creates all kinds of problems with water separation etc. The idle jets are so small that a residue starts to build and clog them. It get's worse over a short period of time. Much like a pear in a oyster. Once it starts it attracts more particles and builds up a clog.
    4. The only way to completely clean the problem is with an ultrasonic cleaner that Yamaha has. Most repair facilities do not have this cleaner as they are about $2500. A typical carb cleaning will NOT do the trick as small particles are still in the idle jets and it clogs quickly after the cleaning.
    5. Once your carbs have been properly services or in some cases replaced you HAVE to start a fuel stabilization regiment. A lot of folks claim that - “MARINE” Formula STA-BIL Ethanol Treatment & Performance Improver – Is the best additive to date. This is what we are currently putting in the tank connected to the F40. The key is to use the additives at EVERY fill up.
    6. I hear rumors that the Idle jets from a 2001 F40 are larger and might work if they are swapped out. I'm not sure on this and would chalk it up to internet rumor until proven otherwise.

    I hope this help. I can honestly say been there done that. :mad:

    I hope your problem is solved quickly. Welcome again.

    Cheers
    Capt. Jan
     

  3. jlanzone

    jlanzone Well-Known Member

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    My engine is currently being worked on by a Yamaha mechanic with the ultrasonic cleaner. All tolled it will have cost me about 1300 dollars in repairs this year, none under warranty. I have used ring free religiously and run the boat almost every week. I buy the gas from I high volume station and yes it has E 10. I have a Racor filter and no water appears in the bowl. I am thinking about repowering and I may go with a Honda 50 which is fuel injecte and weighs less than the Yamaha F40a. The HPX 15 is only rated for a 40 HP max but I sometimes like to make long runs and my top speed is only about 31 wide open. Any opinions on exceding the HP rating on the boat but not overweighing the boat.
     
  4. iMacattack

    iMacattack busy, too busy

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    Ring Free will do nothing for E10. High volume fuel retailers do nothing for the problem. Per Yamaha rep I spoke to. You HAVE to treat the fuel with a stabilizing agent like Marine Sta-Bil or other treatment specifically designed for ethanol fuels. That is the only way to solve the problem. Every time all the time.

    This problem is not going to get better until we can stop using ethanol as a fuel additive. :mad:

    The Honda will be less suseptable to E10 due to the fact that fuel injection is a closed loop system but it's not the cure all.

    Good luck. I feel your pain. So far knock on wood, the Marine Sta-Bil has solved our problem. I know there is a new product that Ron at The Skiff Shop is looking into. As soon as he has more information I'm sure he will share it with us.

    Cheers and again welcome to Microskiff.com

    Capt. Jan
     
  5. Un-shore

    Un-shore Well-Known Member

    Marinas sell e10-free fuel, call around in your area. I would still use the additive just in case. :-?
     
  6. The_Skiff_Shop

    The_Skiff_Shop Well-Known Member

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    The Skiff Shop is stocking Sentry fuel treatment which claims to "clean injectors and carbs - eliminates all fuel / water problems, inhibits Ethanol Phase separation, improves mileage / horsepower, stabilizes / restores fuel, reduces emissions".

    Anybody with the F40 carbed motor can contact me @ theskiffshop@yahoo.com.  I have a proposal for you.

    http://www.sentrytreatments.com/shtml/faqs.shtml

    CR/TSS
     
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