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  1. #1
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    Custom poppet for 225 promax on 1 piece plate

    I've been going back and forth on putting a 2 piece plate on my 225 promax SS. I would prefer to keep the 1 piece plate because the 2 piece plate doesn't mount the best to a 15" 280 mid. I don't feel like cobbling the tiller arm to adapt to a 2 piece. I only run my engine in 60 to 80 degree water temp so I figure I can keep using a 1 piece since that's a narrow range and it's fairly warm water.

    With that out of the way, I was wondering if I could rig up something kind of custom in order to still use the poppet. This is what I have for an idea. I was thinking of putting the poppet back in and then on the poppet cover I would disconect the hose that comes from the top of the motor. I would either cap the top of the motor off or reroute the water somewhere else. Then I would take a different hose and connect it to the poppet cover where the old hose was. I would route that house to the 2nd pee hole on the back of the motor. I would then put brass plugs in the drain holes of the 1 piece plate. I'm thinking of drilling those at 1/8 diameter. These 2 holes would still allow for some circulation but would restrict water enough for that cavity to fill with water and then drain out the poppet cover. Would this work? What are your thoughts?

    Just out of curiosity, what would happen if I completely plugged the drain holes in the 1 piece plate? Not saying I would but I'm just wondering. Wouldn't this just force the water out the thermostat hoses?

    Has anyone modified there 1 piece plate to build temp for a 225 promax? Yes, I'm aware of the John Marles mod but what I don't like about that is I feel the motor would get hot at higher RPM's.

  2. #2
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    You cannot completely block the dumps in the plate, you need some small holes in the one pc adapter to cool the water pump housing or it will melt if there is no water dumping on it. If you plug the holes in the 1 pc and drill smaller holes you need to make sure to dump enough water out the poppet cover (you cannot use a poppet without adding to the 1 pc adapter plate, there are threads on this here and it works). you may also need to dry stack the motor to dump enough water depending on engine temp you end up with. Hold more water in the motor, restrict the dumps and restrict poppet hose dump, heats up the motor. Dumping water faster cools the motor and you do not want that with a Promax. The hoses off the heads are just to remove air really and water will come with it but that water still needs to stay in the motor for the most part.
    1973 Viper - sold
    1978 Viking - sold
    1995 XB02

  3. #3
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    https://www.screamandfly.com/showthr...er-plate/page4

    Read this one, they show how to make your poppet work with a 1 pc plate which sounds like what you want.
    1973 Viper - sold
    1978 Viking - sold
    1995 XB02

  4. #4
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    Quote Originally Posted by rjdubiel View Post
    You cannot completely block the dumps in the plate, you need some small holes in the one pc adapter to cool the water pump housing or it will melt if there is no water dumping on it. If you plug the holes in the 1 pc and drill smaller holes you need to make sure to dump enough water out the poppet cover (you cannot use a poppet without adding to the 1 pc adapter plate, there are threads on this here and it works). you may also need to dry stack the motor to dump enough water depending on engine temp you end up with. Hold more water in the motor, restrict the dumps and restrict poppet hose dump, heats up the motor. Dumping water faster cools the motor and you do not want that with a Promax. The hoses off the heads are just to remove air really and water will come with it but that water still needs to stay in the motor for the most part.
    What's the purpose of the hose on the poppet cover? I've been running a poppet with a 225 on a 1 piece and haven't had any issues but would like it to run warmer.

  5. #5
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    Dumps water, The warmer you want the motor the more you constrict that dump hose or cap it completely. You need to take a look at what you have by pulling the power head to see the adapter plate to tell you exactly what is happening with your engine and the setup to be able to address what you want to do and how to do it.
    1973 Viper - sold
    1978 Viking - sold
    1995 XB02

  6. #6
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    I would like mount a 2.5 promax on my 2.4 offshore mid anyone have tips for me>?

  7. #7
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    use tha 2 piece plates from tha PM mid.. you will need to increase tha size of tha 3 3/8" mounting bolt holes (or use studs in tha can) at tha back of tha plate to match tha size in tha can (best i remember).....this way you can keep tha stock coolin' system and have no problems.... jmo
    Last edited by tlwjkw; 06-24-2022 at 04:21 AM.

  8. #8
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    thank you

  9. Likes tlwjkw liked this post

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