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  1. #1

    94 sl750 rebuild

    First, I would like to thank all for this forum. I have gained a wealth of information useful for my project..

    The project is a 1994 Polaris SL750. I saw this on Craigslist and after a couple of days of thinking about it I approach the owner. The owner said he had not run it for a while and the last time it was run it would only reach 4200 rpms and showed low fuel on the MFD.
    He then took it to the local dealer who incorrectly thinking it was in limp mode, rewired the fuel-sending unit. The dealer also said it had good compression. After this fail to solve the problem, the owner gave up and bought a new machine.

    Visually it looked complete and original. The hull was in good shape except for a large amount of oil in the interior. The impeller and stator looked in good shape. The engine exterior looked fine. No sign of corrosion and it appeared that it was used in fresh-water only. Only obvious damage was a broken steering nozzle. As the price was low, I bought it knowing the engine could be toasted. I have no experience with PWCs but have a lot of experience rebuilding and maintaining outboards and snowmachines.

    Once safely in my garage and with a fully charge battery I did a compression check and got 120/120/110. A quick check of the crank index looked good. I was beginning to think I got I steal of a deal.

    After lots of thought and much reading on this forum, I decided that if I wanted a reliable machine I needed to strip it down and check the engine and pump. If all was good then seals and gaskets would be cheap. This would also allow me to clean the inside of the hull.

    Engine and pump removal was easy. Reading the information here is a lot easier than trial and error. Once I removed the heads and cylinders I found significant scoring on all cylinders and piston. Most scoring was low on the cylinder and mostly on the exhaust side. Pto cylinder had an oversized piston and had the worst scoring. Mag and center pistons were original. I was surprised my compression reading was as high as it was. Heads and piston tops looked good. With the cylinders off I found water in one crank compartment. With the case split and signs of rust on the crankshaft, I knew I could not trust the bearings. I am glad I have lots of time before the lake here in Alaska thaw.

    With many evenings in the garage, I have all the components cleaned and ready to reassemble. I found a low time crank from a wrecked machine. Crank index is check and waiting for seals and 3bond 1211. Cylinders are at the machine shop and once rough bored, I will order a top end kit. The machinist will do the final fit with the pistons in hand. The pump seals and bearings are replaced and set for pump/engine alignment. I have ordered real Mikuni carb kits and the upgraded fuel pump. Fuel lines well be replaced. I suspect a bad fuel sender float but have not got that far. With the amount of oil in the hull, I suspect there was some oil system leaks. I am thinking I will convert to pre-mix. I have a block-off plate coming but have not made a final decision. Several of the cooling line were spliced and full of debris and the thermostat and cooling pop-off valve were removed so I also believe there was some cooling problems.

    Mainly wanted to post this to show my appreciation for the members and the information on this site. It has certainly help me this far and I know in will be invaluable for the completion of my Project.

  2. #2
    ripcuda's Avatar
    Join Date
    May 2010
    Newman Lake, WA
    Welcome to Green Hulk!

    Wow... sounds like you are off to a great start on your project! Glad you found the resources here and that you took the time to read, learn and follow the sound advice. You will definitely be rewarded with a better-than-new running ski when it's all said and done.

    Just a couple thoughts. Don't forget the through-hull-carrier-seals. They are the main water leaking into the hull culprits. If the carrier doesn't ride snuggly on the driveshaft... you might need to replace the bushings inside. Mine was like that... new seals alone still leaked. Wasn't until I replaced the bushings did I finally fix it.

    Another thought. The Polaris oil pump system is pretty reliable. You will use a lot less oil keeping the pump verses pre-mixing. Just be sure to replace the old oil lines, make sure the oil filter is clear and that the oil orifices (?) in the intake manifold aren't clogged. My '94 SLT750 oiling system still works great.

    I'm guessing water in AK is cold... so I would advise keeping the thermostat and bypass valve intact. Mine works good in my cold WA water.

    And don't forget pulling the ride plate and doing a good, resealing job of the intake grate and ride plate. Easy to overlook.

    Look forward to hearing how your project progresses. I love my 750!


  3. #3
    BlueFishCrisis's Avatar
    Join Date
    Aug 2011
    Medina, Ohio, United States
    Make sure you verify the year of the machine you have. The last two digits of the HIN are the hull year. The engine model is indicated on the exhaust side of the motor. This will help indicate the year of the motor. The phrase "bad fuel sender float" seems to indicate a later model one piece pickup and sender, whereas the 94s had a different setup, with a separate sender and pickup.

    Always nice to be certain what you actually have vs what someone claims you have......

  4. #4
    Bing-A-Ding-Ding-Ding, Brrrrrap! Brrrrrrrrrap!!! Polaris_Nut#1's Avatar
    Join Date
    Aug 2006
    Pittsfield, MA
    Welcome Mag, sounds like you are off to a great start.

    Cuda nice call on the oil filters. Think I'm going to change all of mine in the Spring.

  5. #5
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
    near Toronto, Canada

    I expect you have already seen them, but for completeness I shall point out my signature web links, and the info pages therein.

  6. #6
    The machinist call to say the cylinders will clean-up at .5 mm over so have the top end kit on the way. Will not get much done in the next couple of weekends as I will be getting some time on my frozen-water-crafts(snowmachines for those scratching there heads).

    ripcuda, Thanks for the advice. I checked the through-hull-carrier-seals as you suggested. The seals look good, there was no play when slid on the shaft and the grease was good. I will check the ride plate/intake grate. The manual calls for marine grade silicone, any good suggestion of brand and type?

    Bluefishcrisis, It is defiantly a 94. Hull number and engine number all check. The previous owner had issues with the fuel tank being fuel yet MFD showing empty. I am thinking it is a bad float. I will check it out before I re-install the tank and go from there. It could be wiring or the MFD. Are all the round MFD the same?

    K447, I have not only looked at your links but have them bookmarked for quick reference. Thanks for the good info.

  7. #7
    Bing-A-Ding-Ding-Ding, Brrrrrap! Brrrrrrrrrap!!! Polaris_Nut#1's Avatar
    Join Date
    Aug 2006
    Pittsfield, MA
    Quote Originally Posted by Magamish View Post

    The previous owner had issues with the fuel tank being fuel yet MFD showing empty. I am thinking it is a bad float. I will check it out before I re-install the tank and go from there. It could be wiring or the MFD. Are all the round MFD the same?
    test it, 33 full and 240 ohms empty. I had one that read full even when it was empty.
    Last edited by K447; 03-09-2013 at 11:46 AM. Reason: Ohms

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