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  1. #1

    WTB SLX780 Engine(s)

    Hey guys and gals, just bought my first jets skis today, 2 matching 1996 Polaris slx skis. Got them for a screaming deal, only because both engines are shot! Both pretty much threw a rod, one of them cracked the casing. Both threw the rod in the rear cylinder (the one closest to the rear of the ski). Is this common? I have a hard time understanding why both would blow just the rear cylinder, the two front cylinders on both skis are fine. Any advice would be great! two engines would be better =) anyone buy an engine from sbt? PS i powered the display up, and it only shows around 40 hours, I would hope to get more then 40 hours out of an engine.


  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by 510ducati View Post
    Hey guys and gals, just bought my first jets skis today, 2 matching 1996 Polaris SLX skis.

    Got them for a screaming deal, only because both engines are shot! Both pretty much threw a rod, one of them cracked the casing. Both threw the rod in the rear cylinder (the one closest to the rear of the ski). Is this common?

    I have a hard time understanding why both would blow just the rear cylinder, the two front cylinders on both skis are fine.

    Any advice would be great! two engines would be better =)
    anyone buy an engine from SBT?

    PS I powered the display up, and it only shows around 40 hours, I would hope to get more then 40 hours out of an engine.
    Welcome to the Hulk!

    You can find the 1992-1998 Service Manual here.

    The digital MFD displays used on the 1990's models are known to unexpectedly reset themselves to zero hours, often associated with being disconnected from the battery for a long time, or from erratic battery reconnection. So the ski has at least 40 hours, but you wouldn't know if the MFD was accidentally reset 40 hours ago.

    SBT has a very mixed reputation around here. Some are OK with their product, others have very negative feelings.

    SBT does change the specs of the rebuilds from the Polaris OEM spec, particularly in regards to compression and cylinder head shape, which can result in reduced power as compared to a Polaris spec rebuild.

    If you are willing to learn and do the work yourself, you can probably purchased used crankcases and rebuild your motors for about the same cost as SBT. You get to choose the quality of the parts, and you will know exactly how your engines have been put together!

    You can post a WTB (Want To Buy) titled message in the Classified section. I think the Fuji 650, 750, and 780 motors all used the same crankcase (except maybe the 1992-1993 650).
    Edit: Apparently the 780 case is different. That's what happens when I don't actually go and check.

    Do some searching on Green Hulk Polaris - there is a lot of information regarding the common issues and preventative maintenance you will want to do.

    For sure, you want to go through the entire fuel system from inside the tank right through the carbs. Be sure to install good quality batteries when the time comes.

    Why did the PTO cylinder fail on both engines?
    I couldn't say, but others around here with more Fuji experience might know.
    Last edited by K447; 05-27-2008 at 02:23 PM.

  3. #3
    jvhenry
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    K447 I am looking for a 780 crankcase as well or at least the upper half of one. You said the crankcases are the same as far as the 750's and the 780's and if that were true I would be thrilled since I have a spare one for a 750. However the crankcases are not the same as far as I can tell. The 780 has some notches cut out in the top to help with receiving more fuel and the 750 does not have them. If I am wrong then someone please correct me. If the 750 would work in place of the 780 crankcase would there be any losses due to not having the notches to help with fuel? Any input is appreciated.

  4. #4
    Lake Mead Bum & BTLS Mark starflight's Avatar
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    JV, the 650 750 780 cases were all the same till 96 I think. After that they changed the case porting/ stuffing to get 5 more horse power. Went from 90 to 95. You can still use an older cases, but may lose a little power.

  5. #5
    She likes the bike. But the ski gets her wet!!!! xlint89's Avatar
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    JV, 650, 750, and 780 bottom halves are identical. Top halves are not. The 650 and 750 are the same, but you are correct, the 780 top half has the runners to help direct fuel into the cyl ports. A 750 top half will work without any problems. You MIGHT lose an insignifiacnt amount of HP, but I doubt you'd even notice.

    But be warned, some guys on here say that the cases should be a matched set. Not a top from one engine and the bottom of another. FYI

  6. #6
    jvhenry
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    Thanks for the info xlint. I have a matching set for a 750 that I am going to use.

  7. #7

    Smile I have one

    Quote Originally Posted by 510ducati View Post
    Hey guys and gals, just bought my first jets skis today, 2 matching 1996 Polaris slx skis. Got them for a screaming deal, only because both engines are shot! Both pretty much threw a rod, one of them cracked the casing. Both threw the rod in the rear cylinder (the one closest to the rear of the ski). Is this common? I have a hard time understanding why both would blow just the rear cylinder, the two front cylinders on both skis are fine. Any advice would be great! two engines would be better =) anyone buy an engine from sbt? PS i powered the display up, and it only shows around 40 hours, I would hope to get more then 40 hours out of an engine.
    I have a complete motor, that I was told was a running one 3 months ago. I cannot guarantee anything, BUT I will sell you the entire motor package for $300 AS IS, and you can figure it out on your own. If anything, it is a GREAT parts package. Shipping is extra.

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