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Thread: Shaft Alignment

  1. #1

    Shaft Alignment

    I have a 1996 Polaris SL780 that is my winter project. I was pretty much a basket case but I am making progress. When received it , the engine would not turn over at all. I found that the Jet pump was packed with pine needles and locked up. I wasn't able to flush them out, so I pulled the pump and cleaned it out. After removing all of the debris the pump spun freely. I proceeded to get the engine running. Excited by my progress, I reinstalled the pump. I hit the starter button and it was locked up again. Looking closer at the shaft it was obvious that there was an alignment issue. I remember noticing that before I pulled the pump but kinda overlooked it. I thought it was just my eyes.
    I know that the engine can be aligned but it actually looks square in the ski. It looks to me that the shaft is coming in crooked from the pump. Everything seemed to be seated square and correct. I figured before I made things worse, I would check here and see if anyone has ever seen this and might have a suggestion of how to correct it. Thanks.


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  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
    Join Date
    Jul 2007
    near Toronto, Canada

    The engine gets aligned to the jet pump, not the jet pump to the engine. Wherever the jet pump wants the engine to be to make the drive shaft properly aligned, that is where the engine needs to be.

    That said, you cannot use the drive shaft itself to accurately check the alignment. The shaft has play at the impeller, and some at the engine coupler.

    When you had the jet pump out did you remove the tail cone and check for signs of water or rust inside? There must be zero water and zero rust in the stator bearing cavity. And the impeller bearings just turn with zero noise or gritty feel.

    Make very sure the jet pump is properly seated on the pump base. It is possible to have it stuck on one side and tilted where it should seat onto the base section.

    Did you remove the pump base section from the hull? Normally it is NOT removed and is sealed to the hull. Only the four LONG bolts need to be removed, no nuts.

  3. #3
    I left the base bolted to the ski. I didn't check the stator bearings but the impeller spins freely when it's out of the ski. I will check the bearings just to be safe. As far as could tell, the pump was seated correctly but it is really hard to see when it's installed. It seems to me that the alignment is so far out that its binding. It literally looks 4 or 5 degrees out. Is there normally that much adjustment in the engine mounts? I have a parts ski...I'm going to pull that pump and install it. I'll see if I still have the same problem. I really don't want to mess with the engine alignment until I'm sure that's where the problem is. Thanks for the input and advise.


  4. #4
    Banned User
    Join Date
    Jun 2010
    Milwaukee WI
    Reach into the pump tunnel and feel for any gaps between the pump sections with your fingers. Everything should be tight. Not even a fingernail should be able to slip in between the pump sections. Its critical that the pump sections be tight together and straight, or your alignment will be way out. Im guessing that this is your problem, and the impeller is bound up in the wear ring because its sitting in there crooked.

  5. #5
    Rasta Mon Condoms We Be Jammin!!!!! TxPro1200's Avatar
    Join Date
    Aug 2006
    looks like engine is out to me.

  6. #6
    Well it took me a while but I finally got some time and put it into my ski. I took the pump out and carefully cleaned all of the joints then put it back in, hit the button and sure enough it was still locked up. I pulled it back out and started to reinspect everything. I happen to notice a bump in the wear ring. I pulled out the baseplate so that I could get a better look at it. It's shot for sure. There is a small crack and either some water froze in the crack or it was caused by corrosion between the ring and baseplate. Luckily, I picked up a parts ski for free. The parts ski has a a long pump while mine is short. The part ski wear ring and stator are shot but the baseplate is good. The question that I have is: can I use the base plate from a long pump on a short pump? The one I took off of my ski looks like it might have a stainless ring in it but I really don't see any joint. The long pump wear ring/base plate looks like its all aluminum. Do I needed to come up with a base plate with a stainless wear ring in it instead?
    Last edited by skipstr; 07-22-2013 at 10:59 PM.

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