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Thread: Running an OB Jet out of water?

  1. #1
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    Default Running an OB Jet out of water?

    Can this be done w/o damage to the impellar/overheating the engine? Say for fogging the motor at the end of the season or starting up at home before heading out... just to make sure? Is the cooling water drawn in at the intake/foot? Is there an adapter to hook a hose up to to the foot and will standard city water provide enough flow to keep the impellar from cavitating?

    Things that make ya go... hmm

  2. #2
    Member AKMarmot's Avatar
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    Default I wouldn't try it

    Your OB jet unit will burn up the water pump impeller very fast. If you are just turning it over & you should be fine, but I wouldn't run it more than a few seconds. Newer units may have an hose / adapter outlet, old ones you need to try & put in a garbage can/ trough of water.

  3. #3
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    It's a Yamaha F40 jet. New but not a 2010 model so I don't think it's injected. Just some background in case somebody knows something I don't about this particular model.

  4. #4
    Member jkb's Avatar
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    Default

    You should be able to get a adapter that hooks into the jet and you can hook a garden hose to it check at yamaha.
    Life is not a journey to the grave with the intention of arriving safely in a pretty well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming-----WOW-----what a ride!
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  5. #5
    Member Dirtofak's Avatar
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    Default

    From:
    http://www.sschapterpsa.com/rambling...aintenance.htm

    Here is what the older style adapters looked like. The new ones are longer and are made mostly of plastic.

    http://www.sschapterpsa.com/rambling...%20adapter.JPG

    See the grease hose here. Look at the 14 MM bolt above it. That is where you hook up the hose adapter.

    http://www.sschapterpsa.com/rambling...ke%20Skirt.JPG

    Some great reading material!

    Hope this helps!

    Mike

  6. #6
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    Default

    thanks a meelion.

  7. #7
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    The F40 should have a factory installed garden hose adapter on the right side of the motor about where the cowl meets the case. It's a 1/4" black tube with a hose end that should be screwed onto a keeper to secure it. If not, you can start and run the motor out of the water for short runs with no damage. Like to fog it or confirm your impeller isn't too tight in the cone. As the weather turns cold in fall I always tilt my motors and run them to clear the water out of the passages so they won't freeze. I've done it for 25 years with OB jets and nothing bad has ever happened to a water pump or anything else. I fog on dry land without water as well. Even with my F40 jet. And run it on dry land in spring to burn out the fogging oil and make sure it'll run before I put it in the water. I have the hose attachment on the engine but no water is available where that boat lives.

  8. #8
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    Default Just bought an adapter

    Actually I just bought two adapters, the first one didn't work. If the jet unit is a factory (gray) jet unit then you can get it from your Yamaha dealer, if it is an aftermarket jet unit (red) then you'll need to get the adapter from a dealer of any other brand of outboards. The Yamaha jet units are 8mm bolts and the red jet units are 3/8" bolts. At least that's how it worked with my mid-90's Yamaha with a red aftermarket jet unit...

    Once you get the right one it works great!

    Chris

  9. #9

    Default impeller clearance

    Quote Originally Posted by Mr. Pid View Post
    The F40 should have a factory installed garden hose adapter on the right side of the motor about where the cowl meets the case. It's a 1/4" black tube with a hose end that should be screwed onto a keeper to secure it. If not, you can start and run the motor out of the water for short runs with no damage. Like to fog it or confirm your impeller isn't too tight in the cone. As the weather turns cold in fall I always tilt my motors and run them to clear the water out of the passages so they won't freeze. I've done it for 25 years with OB jets and nothing bad has ever happened to a water pump or anything else. I fog on dry land without water as well. Even with my F40 jet. And run it on dry land in spring to burn out the fogging oil and make sure it'll run before I put it in the water. I have the hose attachment on the engine but no water is available where that boat lives.

    Hope I'm not hijacking this thread, but how do you check/adjust impeller to cone clearance? Yamaha F150 w/jet
    "If your not the lead dog.... the view never changes"

  10. #10

    Thumbs up

    Sorry, just got around to reading dirtofak's post links, pretty much gives it all.
    "If your not the lead dog.... the view never changes"

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