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  1. #1
    PWCToday Newbie
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    Older SeaDoo hard to start in water.

    Hey guys.

    Ive searched all over for this but havent found anything that matches my symptoms.

    Its the classic, will start on a trailer with no problem, hot or cold, one push and it fires right up, even without the choke.

    Put it in the water and youve got to turn it over for a solid 2-3 minutes before it will fire up.. once it does it runs good, but if you kill it on the water, its another 2-3 minutes of cranking it over before it fires up. but once its running, it runs good.

    About 135-140 psi in both cylinders.

    1989 SP 580 Yellow motor.

  2. #2
    PWCToday.com Is My Home Away From Home bills86e's Avatar
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    Re: Older SeaDoo hard to start in water.

    Bad Compression is usual cause whem prop goes under load of being in water.

    You should always do a compression test whenever a mechaniacal problem is suspected to be sure the engine health is in top shape. The extra load on the engine with low compression is gonna be hard to start in the water. On the trailer there isn't any load on the impeller, so it will start fairly easy. Here is some information to doing a compression test;
    You will need a good brand compression tester. Go to Auto Zone. I think they sell for like $25.00. The compression gage, will screw in the cylinder head in place of the spark plugs. To test compression, remove both spark plugs. Place spark plug caps on the plug cap studs near the cylinder head to ground the empty caps from causeing a fire from arcing. Using the correct adapter for the threaded end of the tester,(same length of the spark plug threads length) screw in the tester in one plug hole.
    Hold the throttle wide open. Push the start button. Watch the compression gauge, when it peaks out at the most compression, let go the start button. Read the psi number. I would do it 3 times to be sure it is accurate. Check both cylinders the same way. The ideal compression is 150 psi per cylinder. If it is less, it's not a problem as long as they are close to being the same. If the psi is less than 120 it might (IS) time for a top end tear down and a rebuild.
    If the psi in 1 cylinder is say 140 psi and the other is 80psi you definately need to tear down and repair. This difference is a lot then there is the problem. I hope this helps you.

    There is one thing between the Carb's fuel pump and the fuel chamber inside the carbureator. It is the needle valve assembly. Gas either gets past it, or it does not get past it.

    How can gas get past a needle valve other than what we have talked about? One way is if the fuel tank pressure release check valve in the OUT vent line is not functioning. The fuel pressure in the tank overcomes the spring tension on the needle valve and gas is FORCED past it.

    If the ignition timing were off enough, it could be hard to start
    If the allowable clearance of the RV is too loose it could be hard to start. You can feeler gauge to check and re-machine the Cover Plate to fix that.
    Same if it has an air leak, it would be hard to start. A faulty ignition pickup can make it hard to start. Weaker than normal spark can make starting more difficult.

    So yes, there are other reasons a motor can be hard to start. crankshaft seals when cold are contracted and when they heat up they expand and start to leak RV cavity oil into left or right or both sides of the case and into the fuel/air mix.

  3. #3
    PWCToday.com Is My Home Away From Home justforfun's Avatar
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    Re: Older SeaDoo hard to start in water.

    He posted the compression numbers why the long post. LOL

    It can be as simple as carbs leaking fuel. Most ski's will start easy on the trailer even if they have a problem. When it's hard to start are the plugs wet from fuel?
    If you have a N/S leaking it will be hard to start.
    remove the plug boots and trim back the plug wires a bit to make sure you have good wire at the boot.

  4. #4
    PWCToday.com Is My Home Away From Home Grumpy Old Guy's Avatar
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    Re: Older SeaDoo hard to start in water.

    My bet is the chitty carb,those old round body carb with the external pump are pure garbage.

    Get a SBN from a white 580 motor & lose all your problems.

  5. #5
    PWCToday Newbie
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    Re: Older SeaDoo hard to start in water.

    Well i pulled the spark plug caps off and cut about a 1/2 inch off.

    I also noticed a small chip out of the wear ring right by the rear side of the impeller.. i didnt actually remove any part of the pump but was just looking inside.

    About the SBN swap.. is it just a straight up carb swap or is there more to it?

  6. #6
    resident guru 1fastski's Avatar
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    Re: Older SeaDoo hard to start in water.

    if it starts out of the water every time , next time you put it in the water and it dont start , get help lift the back of the ski out of the water at least to the exhaust , if it starts right up , it is prob your rotary valve clearance . could also be the carb if your plugs are wet . the swap is easy on the carb .
    i like to help people ,if you own a PWC you need help iam here
    WWW.1fastski.com

  7. #7
    PWCToday Newbie
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    Re: Older SeaDoo hard to start in water.

    Is the rotary valve somthing that can be shimmed.. or if the clearance is out of spec, does it need replacing?
    And what clearance are we talking here? between the valve and the body (like up and down or side to side)... or between the cases and the shaft (back and forth)?

  8. #8
    PWCToday.com Is My Home Away From Home jerrspud's Avatar
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    Re: Older SeaDoo hard to start in water.

    get the shop manual for your ski. (top of forum) The manual talks about RV clearance and hard starting. It's not the RV that wears, it's the cover.
    Jerr
    SeaDoo FAQs
    Kawi FAQs

    92 Kawasaki 550SX 89 550PP, 44MM SBN carb, Westcoast exhaust, Mariner head, OceanPro rideplate
    90 Sea-Doo SP Quadra-Fin rideplate, Solas 14x19 prop, Tuned Pipe, 147 RV, Mariner intake manifold , 44MM SBN Carb, K&N performance arrestor, 91 XP hood
    96 Sea-Doo SPX X4 Hull- R&D rideplate, NuJet prop, RAM cup holder, Commercial Tiny Tach
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