Help! Water entering exhaust causing no start
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  1. #1
    PWCToday Newbie
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    Help! Water entering exhaust causing no start

    I have an issue where I can put the boat in water cold, wait any amount of time, then when I get to the boat it starts right up in water without issue.

    However, after running it for a little bit, then shutting it off, I clearly hear water trickling / dribbling / pouring into the resonator (connected with the rubber host to the end of the tuned pipe). If I clamp off the hoses to the water regulator the water dribbling sound stops.

    The only way I can get it started when it's warm is to clamp off the water hose form the jet pump and the water hoses on the water regulator. Once I do this, the boat needs a few seconds to clear the water from the exhaust and then it fires right up!

    RV is perfect at .0125 clearance, compression is 140 each cylinder, carbs are rebuilt with brand new Mikuni parts including brand new Mikuni needles and seats and pop off is set to 35 PSI. None of these things are the reason for the no start condition.

    The water is infiltrating the exhaust in a way that the engine cannot start unless I clamp those hoses off. Also, no water is getting into the cylinders as I can pull the plugs and they're both dry and a perfect mid brown.

    Any ideas on why water is able to get into the exhaust and cause this? Should the water regulator actively allow water to pour into the resonator only when the boat is hot and when it's off and sitting in water?

  2. #2
    PWCToday.com Is My Home Away From Home wmazz's Avatar
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    Re: Help! Water entering exhaust causing no start

    As I recall, a picture was posted on another forum. That RV cover
    had extreme water damage to the rv cover, rv valve, and I assume
    the pistons.

    Just from what I observed in the picture, I suspect the engine has
    water damage that would affect the engine starting. It is time to
    look at the piston skirts with the power valves, or exhaust manifold
    removed (no mention of the model and year).

    Obviously water was spraying into the flame arrestor while the
    engine was running. Maybe the gray driveline cover is missing.

    After the engine shuts off, all the water drains out a hose into the
    exhaust outlet. Water is prevented from entering the cooling supply
    hose by the hose height over the water line. If the hose is longer
    and sagging below the water line, or the hull is taking on water, it
    is possible for water to reach the water box.


    Bill M.

    If the piston skirts have bad water damage, the engines ability
    to create pressure and vacuum for the carbs is diminished.

    Chances are the RV cover is worse than you think.
    Horsepower == Speed, RPM != Speed



  3. #3
    PWCToday Newbie
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    Re: Help! Water entering exhaust causing no start

    Quote Originally Posted by wmazz View Post
    As I recall, a picture was posted on another forum. That RV cover
    had extreme water damage to the rv cover, rv valve, and I assume
    the pistons.

    Just from what I observed in the picture, I suspect the engine has
    water damage that would affect the engine starting. It is time to
    look at the piston skirts with the power valves, or exhaust manifold
    removed (no mention of the model and year).

    Obviously water was spraying into the flame arrestor while the
    engine was running. Maybe the gray driveline cover is missing.

    After the engine shuts off, all the water drains out a hose into the
    exhaust outlet. Water is prevented from entering the cooling supply
    hose by the hose height over the water line. If the hose is longer
    and sagging below the water line, or the hull is taking on water, it
    is possible for water to reach the water box.


    Bill M.

    If the piston skirts have bad water damage, the engines ability
    to create pressure and vacuum for the carbs is diminished.

    Chances are the RV cover is worse than you think.
    So my RV is in spec and has no prob starting when cold in water. It also has no problem starting when hot in water if I pinch those water lines. The compression on both cylinders is 140 PSI and no water is in the cylinders or spraying form the intake. I have no water leaks in he hull either. But water pours into the resonator after I've run the boat for a while coming in form the jet pump water inlet and into the water flow regulator. I pinch the hoses and it start without issue.

    I think if the RV or compression was in question the boat wouldn't be able to start at all when hot in water. I should also add that when I was having these issues I would frequently check the plugs. They're never wet and a perfect dry medium brown color so I know it's not flooding or fouling with either fuel or water. There is no water getting into the engine. And from what I can see, there are no signs of water damage on my cover, block, inside the engine or otherwise.

    Also, here is a picture of my cooling lines. Do you see something off here?

    Thank you!!!
    Challenger-Cooling.jpeg
    Last edited by mejim; 08-03-2022 at 05:03 PM.

  4. #4
    PWCToday.com Is My Home Away From Home WFO Speedracer's Avatar
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    Re: Help! Water entering exhaust causing no start

    Sounds like you need a new water regulator and I would take that slack in the hose and loop it up so that water cannot enter the engine or exhaust unless it is running, water will not run uphill.
    Y'all know me, still the same O.G. but I been low-key
    hated on by most these &^$$@s with no cheese, no deals and no G's, no wheels and no keys, no boats, no snowmobiles, and no skis, mad at me cause I can finally afford to provide my family with groceries

    WWSRD , What would Speed Racer do ?

  5. #5
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    Re: Help! Water entering exhaust causing no start

    Could you imagine, if all this time trying to figure out why I can't start when the engine is hot, was just because the hose was supposed to be tied up higher?

    I'm going to try this because that would be unbelievable lol

    As for the water regulator though, I inspected mine and it appears that water is supposed to go into the exhaust from the base of the water regulator. And all the parts look brand new. It looks like this think is in pristine condition. Bellow is good, clamps are good, and there was no dirt in it.

    Thank you!
    Last edited by mejim; 08-03-2022 at 05:54 PM.

  6. #6
    PWCToday.com Is My Home Away From Home WFO Speedracer's Avatar
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    Re: Help! Water entering exhaust causing no start

    I can tell you that it is not routed from the factory the way it is now, that's for sure, if you have to drill a small hole in the lip for the divider and zip tie it up there, anything to make a high loop wher water cannot enter as it does now.
    Last edited by WFO Speedracer; 08-03-2022 at 05:57 PM.
    Y'all know me, still the same O.G. but I been low-key
    hated on by most these &^$$@s with no cheese, no deals and no G's, no wheels and no keys, no boats, no snowmobiles, and no skis, mad at me cause I can finally afford to provide my family with groceries

    WWSRD , What would Speed Racer do ?

  7. #7
    PWCToday Newbie
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    Re: Help! Water entering exhaust causing no start

    Quote Originally Posted by WFO Speedracer View Post
    I can tell you that it is not routed from the factory the way it is now, that's for sure, if you have to drill a small hole in the lip for the divider and zip tie it up there, anything to make a high loop wher water cannot enter as it does now.
    I rerouted the hoses to loop up behind the rear barrier around the same height as the exhaust.

    Iíll try this out tomorrow but logically speaking this makes total sense!

    Thank you!

    3D0EB0F7-FFD3-4037-9C55-F41C5240FDB8.jpeg

  8. #8
    PWCToday Newbie
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    Re: Help! Water entering exhaust causing no start

    IT'S FIXED!! Rerouting the water lines and creating a high loop for both the flush and jet pump inlets resolved it. There is no longer a dribbling of water filling the resonator or engine and now the boat will without fail start every time when I shut it off on water. It's epic!!

    I now have freedom to go anywhere on the lakes and dock it without having to worry about a tow lol Last time I went to a dock I was with a friend and many miles away from the car. We go stuck and it would not start no matter what I did. We had to be towed all the way back! Got to meet some awesome people but that was embarrassing.

    All good now though! Thank you so much for the advice on this! It works!!

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