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  1. #1

    PreMix or keep oil injection system?

    Hate to bother anyone with this but I can't find the answer/opinion I'm looking for. Would anyone recommend doing away with the oil injection sys on my slt 780 and running pre mix? Your thoughts on this would be greatly appreciated, thanks!


  2. #2
    RiverRat19405, im a rat in the water RiverRat19405's Avatar
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    i would all 4 of my ski's are pre mix if the oil pump should take a crap Kaboom!! just my 3 cents though

  3. #3

    Cool

    Quote Originally Posted by RiverRat19405 View Post
    i would all 4 of my ski's are pre mix if the oil pump should take a crap Kaboom!! just my 3 cents though
    Exactly what I was thinking.

  4. #4
    Click avatar for tech links/info, donation request K447's Avatar
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    Opinions exist for both options. Those who worry about the accumulated years on the original oil pump parts, like to go pre-mix.

    Those who have seen very few oil pump failures, and prefer the simplicity of just fueling up without remembering the oil mix, prefer to leave the oil injection system alone.

    I think, but don't know where to find confirmation, that oil pumps from other brands tended to fail more often in the early years than the Polaris pumps, but the fear of engine failure from oil pumps has carried across the brands.

    My understanding is that the oil pump varies the oil ratio, and in doing so burns less oil overall than a fixed pre-mix ratio, for the same amount of riding. So pre-mix will cost a little more in terms of oil purchases, over time.

    Polaris 2-stroke engines that are fuel injected (which I have) can not use pre-mix, so they must rely on the oil injection system.

    If the oil pump fails, then the engine will be damaged.
    If someone fuels up a pre-mix PWC without mixing in the correct oil mix, or no oil at all, then the engine will fail.
    Which is more likely in your case, over time; mechanical failure, or human error?

  5. #5
    Thanks for your input K447! Since I've ran 2 Stroke motorcicles most of my life mixing fuel is no burden nor a problem to remember. I know oil injection has been around for decades however I also know sh*t happens and when it comes to relying on something I can't monitor I feel a whole lot more comfortable taking the extra time and spending the extra money to have the reassurance.


    Quote Originally Posted by K447 View Post
    Opinions exist for both options. Those who worry about the accumulated years on the original oil pump parts, like to go pre-mix.

    Those who have seen very few oil pump failures, and prefer the simplicity of just fueling up without remembering the oil mix, prefer to leave the oil injection system alone.

    I think, but don't know where to find confirmation, that oil pumps from other brands tended to fail more often in the early years than the Polaris pumps, but the fear of engine failure from oil pumps has carried across the brands.

    My understanding is that the oil pump varies the oil ratio, and in doing so burns less oil overall than a fixed pre-mix ratio, for the same amount of riding. So pre-mix will cost a little more in terms of oil purchases, over time.

    Polaris 2-stroke engines that are fuel injected (which I have) can not use pre-mix, so they must rely on the oil injection system.

    If the oil pump fails, then the engine will be damaged.
    If someone fuels up a pre-mix PWC without mixing in the correct oil mix, or no oil at all, then the engine will fail.
    Which is more likely in your case, over time; mechanical failure, or human error?

  6. #6
    Connecticut CrazyA's Avatar
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    Quote Originally Posted by bbrown2804 View Post
    Hate to bother anyone with this but I can't find the answer/opinion I'm looking for. Would anyone recommend doing away with the oil injection sys on my slt 780 and running pre mix? Your thoughts on this would be greatly appreciated, thanks!
    Most performance guys (which is what most of us here on the Hulk are) will tell you to go premix just to be safe.

    Quote Originally Posted by K447 View Post
    My understanding is that the oil pump varies the oil ratio, and in doing so burns less oil overall than a fixed pre-mix ratio, for the same amount of riding. So pre-mix will cost a little more in terms of oil purchases, over time.
    That's correct. The amount of oil used running premix vs. injection is monumental!!!


    .

  7. #7
    johnsonmtz's Avatar
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    I have a '96 SLT780 and I did remove the injection system on mine after my first reman engine toasted CEN due to a cracked oil line. Yes I could have just put on new lines along with the new engine and probably could have been okay, but I didn't want the risk of a total kaboom again.

    Yes, my engine is down again due to a lean condition on PTO, but it's not an oil problem this time.

    KJ

  8. #8
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by CrazyA View Post
    ...The amount of oil used running premix vs. injection is monumental!!!
    Do you have any numbers on the consumption difference?

    It sure seems like a tank of oil (roughly 5 liters?) with the oil injection system runs for a LONG time before needing a re-fill. The same amount of oil would be good for about 4-5 tankfuls of gasoline with pre-mix.

  9. #9
    Tony's Avatar
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    Everybody always chimes in to these premix threads about pump failure, but I don't recall ever reading about a failure. Johnsonmtz has already mentioned a cracked line caused his engine failure. And let's not forget plugged orifices, leaking clamps, and broken/rusted/misadjusted cables as potential problems.

  10. #10
    johnsonmtz's Avatar
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    Quote Originally Posted by Tony View Post
    Everybody always chimes in to these premix threads about pump failure, but I don't recall ever reading about a failure. Johnsonmtz has already mentioned a cracked line caused his engine failure. And let's not forget plugged orifices, leaking clamps, and broken/rusted/misadjusted cables as potential problems.
    I have to admit that I sort of fell for the "oil injection can kill your motor" hysteria. However, after having dropped nearly $1,000 on a reman I didn't want to take the chance of some small piece breaking and throwing that money to the bottom of the lake. So, I took the cheap road, installed a blockoff plate, and went premix.

    How much more oil do I use I'm not really sure, but I can buy a whole bunch of Amsoil and pre-mix it before I equal the cost of a new engine.



    I have to premix for my outboard (1979 vintage), so doing this is no big deal. Plus, I use a Sea-Sense graduated mixing bottle so it takes the guess-work out of the oil addition.

    KJ

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