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  1. #1

    Join Date
    Jun 2009
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    New guy with some questions !

    Hey guys, I recently picked up my first seadoo, a 98 sltx 1050, the thing was in pieces when i bought it for 200 bucks. it looks like the last guy must have ran dry on the oil, the damage was both outer cyl's, they had blown the rings right off, and massive indentations in the pistons, and heads. So since ive had it the last 3 months, I've pulled everything apart cleaned er up and replaced all the gas/oil lines, cleaned out the tanks, re-assembled pretty much everything, got the cyl's bored out .75 over, got new pistons, opened up bottom end and crank and bearings look/feel brand new.

    Now my first question is, what all do i need to do to bypass the oil pump. do i just need to remove the unit and add the cover? Should i keep the unit and not premix ? the unit seems to be working fine, and most of the lines seemed to be ok, so i don't know if the guy ran dry or what happened.I know i'de feel better knowing my oil is in the gas.

    Second, the last guy i got it from who pulled the motor out of it just cut the wire harness about half way between the motor and cdi box. I was planning on just soldering and shrinkin the wires, but will this cause any problems? will it be ok if i do that or do i need a new harness?

    And now lastly.. i have been searching on this site and others for any type of info on this machine as i don't know to much about it ie) reliability, areas to improve or modify etc. if anyone could shed some light it would be awesome !


  2. #2

    Join Date
    Jul 2007
    Location
    Alabama Gulf Coast
    Posts
    206
    question 1) well you kinda answered that one yourself. If you feel better knowing the oil is in there, block it off and mix 40:1. I went to premix on my 750 but am thinking about going back. Word is that these polaris oil pumps are very reliable. Just replace the lines and filter and go with it. If you choose to go premix, you can buy a block off plate or what I did was pull the drive gear shaft out and reinstall the pump as a block off. Seems to be fine.

    #2)You will not need a wiring harness but instead of soldering the wires back together, get some waterproof connectors to put them back together.This will make the job of removing the engine easier should it ever be needed. I will try to come up with the info on those but it escapes me right now.

    #3)Download the service manual from the tech section and start reading.
    I really do not know enough about the domestics to give specific guidance but I'm sure the standard filters,fuel lines, electrical connections stuff should be looked at,checked, and changed just for peace of mind.

    Hopefully I've not muddied the water for ya.

  3. #3

    Join Date
    Jul 2007
    Location
    Alabama Gulf Coast
    Posts
    206
    Well I did it again!!
    Welcome to the Hulk Dollaman!!!

  4. #4

    Join Date
    Jul 2007
    Location
    Alabama Gulf Coast
    Posts
    206
    Here is where to get your manual and a whole pile of info about pwc's in general.

    http://pwcmanuals.shorturl.com/

    Here is a link to the connectors I was talking about

    http://www.pegasusautoracing.com/gro...ID=WEATHERPACK
    I've not come up with the oil pump block off plate for your ski yet but will let you know if I come up with it.

  5. #5
    Click avatar for tech links/info, donation request K447's Avatar
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    Welcome to the Hulk

    The red 'domestic engine' oil pump mounting and drive is different from the blue 'Fuji engine' oil pump. The oil pumps are reliable, as long as the oil hoses, clamps and filter are in good condition. Do make sure the oil lines are primed, at least down to the pump itself.

    The service manual tells you how to bleed the air from the oil line using the bleed screw on the oil pump.

    While you are breaking in the new top end rings, you should add some oil to the fuel anyway. About 50:1 ratio should be fine for break-in, with the oil pump in place. With oil pump removed, break-in pre-mix is 32:1, then 40:1 after break-in.

    There is a specific break-in process for these engines, with a few variations. The core of it is to heat cycle the engine several times, with increasing range of throttle after each warm up, followed by a thorough cool-down.

  6. #6

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    Jun 2009
    Location
    Cambridge, Canada
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    thanks for all the quick replies ! I downloaded the manuals before i even got the doo lol, and ive replaced all lines and done a bunch of things, however i have yet to find a reason for lack of oil. I was assuming it was heat due to lack of oil that blew this motha, but now im questioning myself. i really dont wanna blow it up after all my work lol. Im gonna try and get a pic up, but to describe the damage, the pistons were dark black on top, with good indentations in them one about a the circumfrence of a quarter (.25cents) like a dent. the scoring on the cylinders was really bad on the exhaust side, and the top rings were pooched .,, so seeing that i assumed lack of oil am i wrong ? should i put up a pic ?

  7. #7
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by dollaman View Post
    ...I have yet to find a reason for lack of oil. I was assuming it was heat due to lack of oil ...but now im questioning myself.

    ...I'm gonna try and get a pic up, but to describe the damage, the pistons were dark black on top, with good indentations in them one about a the circumference of a quarter (.25cents) like a dent.

    the scoring on the cylinders was really bad on the exhaust side, and the top rings were pooched .,, so seeing that i assumed lack of oil am i wrong ? should i put up a pic ?
    I think your pictures will confirm that the damage was caused by lean burn.

    When the fuel delivery is inadequate/lean (often caused by clogged carbs or weak fuel delivery), the temperature of the piston tops get so hot the aluminum melts.

    It gets hottest in the center, and often melts a hole right through the piston! Sometimes the piston edges and rings also suffer from the excess heat, which can score the cylinders.

    If you still have the old spark plugs, they probably show some gray tint. That is melted aluminum from the pistons being deposited on the spark plugs.

    A properly tuned engine will have a thin black coating on the piston tops, with small areas near the ports of clean metal (fingernail sized). This is called the piston wash, and is the result of high velocity fuel mist washing the carbon off the piston near the ports.

    Lear burn damage is one of the more common ways to damage these engines. Sometimes, the engine even seems like it is running very well, but if it is running lean, the pistons will fail.

    Attached photos show pistons with lean, normal, and too rich piston wash patterns.

    Normal wash patterns vary with the engine and how it is run, but you always want some wash pattern
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  8. #8

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    ok here are some pics i think ..
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  9. #9

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    This is the exhaust side
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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  10. #10
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by dollaman View Post
    ...here are some pics...
    I was wrong. It is not lean burn damage. The piston wash patterns look good on two of the pistons, almost too rich. The black piston was running close to lean.

    The damage in two of the cylinders is foreign object damage, probably the needle rollers from failed rod bearings. When those bearings fail, the little rollers get loose in the crank case, and get blown up above the piston through the transfer ports. They then get hammered between the piston top and the head, and eventually get blown out the exhaust port.

    If the upper rod end bearings (piston wrist pin bearings) are the only ones that have failed, and the crank shaft bearings are still OK, then you may be able to get away with just rebuilding the top end on those two cylinders. New heads, pistons kits, etc.

    The big question will be - is there any metal debris still inside the crank case? If there is, it can re-damage the repaired engine.

    The alternative (required if the lower bearings are damaged) is to pull the crank case apart. If any of the lower bearings are bad, the crank shaft will need to be professionally rebuilt.

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