20 hp Tohatsu fuel issues

Discussion in 'Dinghies' started by Carpediem44DB, Jan 20, 2021.

  1. Carpediem44DB

    Carpediem44DB Well-Known Member

    Aug 18, 2015
    Sanfransico Bay area
    Recently sold and currently buying a 2000 Carver 506
    2006 44 DB Sedan Bridge
    Cummins QSC 8.3 500 HD
    A fellow CSR member has a Tohatsu 20 horse outboard on his 10 foot dink. Lately it has been running rich and stalling when power is reduced to idle at neutral and stumbling in mid range power . We noticed too that there is a strong smell of raw fuel and a sheen on the water after the engine quits. We traced the fuel to the hose attached to the bottom of the fuel bowl. Does anyone know what condition would cause fuel to drain from there? Clearly its by design to overboard the fuel but would it be a mixture adjustment or a float valve leaking past? Ideas?
    Carpe Diem
  2. blaster

    blaster Well-Known Member SILVER Sponsor

    May 23, 2011
    potomac river
    2010 sea ray 205 sport
    F-250 CCLB 6.2 4x4 3.73 rear.
    Mercruiser 4.3 mpi alpha 1.62
    Is the needle stuck open? Pull the carburetor and check that the float is okay.
  3. ocgrant

    ocgrant Well-Known Member GOLD Sponsor

    Dec 31, 2006
    Miami / Ft Lauderdale
    H2O Therapy
    2006 Sundancer 48
    Novurania 460
    Yamaha EX-R
    Cummins QSC 540's
    Rebuild the carb... I do my Yamaha every 2 years.
  4. Carpediem44DB

    Carpediem44DB Well-Known Member

    Aug 18, 2015
    Sanfransico Bay area
    Recently sold and currently buying a 2000 Carver 506
    2006 44 DB Sedan Bridge
    Cummins QSC 8.3 500 HD
    There is a Tohatsu dealer/ service shop not too far away, I advised him to take it there for a complete service and carb rebuild. He will be much happier and so will I:)
  5. Pirate Lady

    Pirate Lady Active Member

    Jun 2, 2020
    Chesapeake, middle river
    91 250 Sundancer, like new, gorgeous, no you can’t buy it.
    The BIG one.
    Guys, I read the sailing magazine websites. Blue water off-shore trans-ocean sailing. Amazing stories on there. Good stuff. They all bitch about how ethanol fkd up outboards. But the farm lobby is bigger than the motor/boats lobby. Do you know that if you put gas with ethanol in your engine it voids warranty? Ya. I live in Maryland. There is no pace to get fuel without it.
  6. SKybolt

    SKybolt Active Member GOLD Sponsor

    Nov 11, 2014
    Kent Narrows, MD
    1988 460 EC
    Detroit 6v92TA
    (Low profile's)
    Alison Gears
    12.5kw Genset
    It's totally the carb needing cleaning out. Rebuild is bad term for it, but thats what it is called. The low speed passage and jet get clogged with micro crap from ethanol and causes this. Like @ocgrant said, every two years for sure. Even new outboards have this issue. Big PITA for sure.
  7. The Bill Collector

    The Bill Collector Well-Known Member GOLD Sponsor

    Jun 2, 2008
    Tacoma, WA
    1998 450 Sundancer, Achilles dinghy
    3126 Cat's
    I just disconnect the fuel connection to the motor every time and let the motor run until it dies... Never had to rebuild anything 10+ years running.
    LG111 likes this.
  8. Jeremygavin

    Jeremygavin Well-Known Member GOLD Sponsor

    Mar 6, 2012
    Cape Cod, MA
    2011 520 Sedan Bridge
    2016 Sea Ray 19 SPX OB
    2019 Walker Bay Generation 340
    Cummins QSM11s
    Mercury 150 Fourstroke
    Honda 40hp
    I agree with this, I do the same. Key is to burn off all the fuel so it can’t evaporate in the carb and leave the tarnish behind.
    The Bill Collector likes this.
  9. Ike

    Ike Active Member

    Dec 17, 2011
    Pacific Northwest
    1972 Sea Ray SRV 190 I/O
    12 Ft Rowboat
    8 Foot Sailing Dinghy
    Mercruiser 165 6cyl inline GM 250
    I had a 4HP Mecr (Tohatsu under the hood) for about 7 years. It did the same thing. Took it to the shop. They cleaned the carb. Ran fine after. But eventually traded it in on a 9.9 Suzuki with fuel injection. No problems since.

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