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  1. #1

    1996 SL 780 question

    This thing is smoking and smoking and smoking...bad enough that its fouling the plugs....Anyone have any idea as to why this thing smokes so bad...Is there a way to adjust the oil pump...any help or ideas would be greatly appreciated....Thanks


  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
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    Welcome to the Hulk

    Have you checked the linkage between the oil pump and the carburetor throttle?

    You should also check engine compression, especially if you are not getting full engine RPM at wide open throttle in the water.

    If both of those are good, have you checked that the carb screws are set correctly, and you are using the correct spark plugs for that engine?

  3. #3
    Lake Mead Bum & BTLS Mark starflight's Avatar
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    Welcome to the Hulk! Download the manual here. You also can find some more good info here.
    Whats the history of this machine? Did it do ok last yr? Could it be possible that the fogging oil is being burned off?
    It's possible that the linkage that connects the pump to the carbs has fallen off, and it defaults to full flow if that happens. The linkage can be seen in the pic.
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  4. #4
    ran fine last year....compression is good...125/125/120...linkage is still hooked up and appears to be working...too good...thought is was the fogging oil...but after 1/4 tank of gas...i would think it would be cleaned out....within that 1/4 tank of gas..it used 1/2 tank of oil....is there any adjustment on the linkage for the oil pump...i dont know what else to check..am looking at the option of premixing....Would like to keep pump if i can but am lost on whats wrong

  5. #5
    anymore ideas from anyone

  6. #6
    Click avatar for tech links/info, donation request K447's Avatar
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    Quote Originally Posted by convincer View Post
    ...linkage is still hooked up and appears to be working...too good...
    Did you actually check that the linkage is hooked up correctly, as described in the service manual?

    These oil pumps have a spring loaded control arm. If the linkage falls off, the oil pump arm swings back way past the normal idle position. If the linkage is reconnected with the arm on the wrong side of the pump, it will pump oil at a 100% rate, even at low throttle positions.

    What kind of oil are you using?
    Is it good quality, TC-W3 or better?
    Synthetic or regular oil?

    Have you checked the carb low speed screws for correct settings?

  7. #7
    i will read the manual on the pump..i open the throttle and can see that the oil rod linkage is hooked up and moving when the throttle is moved...or is there more to it than that..im running quicksilver PWC oil from Merc..Have been running it for 3 years now and no problems...Has never smoked like this before

    Could the carb screw settings have changed just from sitting in the garage over winter?...Im not saying that it cant happen but i treated the fuel at the end of the season and winterized it..(no need to since it sits in my heated garage...i keep the garage(shop) at 72 degrees in the winter as it is my snowmobile repair shop..where i service a couple hundred sleds a season from as far as 100 miles away)...so im not completely dumb to mechanical work and how things work...but im not perfect...but this one has me baffeled

  8. #8
    The oil pump linkage is hook up and working as it should.....Checked the H/L screws..they are correct....plugs are soaked black with oil.....checked spark again...good spark on all three cylinders.....how common is it for the pumps to go bad...if they do go bad can they pump to much or would it be an oil starvation problem..im outta ideas...like i said earlier..i ran 1/4 tank of fresh fuel thru it and smoked like crazy and used 1/2 tank of oil.....any thing else to check

  9. #9
    Lake Mead Bum & BTLS Mark starflight's Avatar
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    The fittings where the oil line attaches is actully a type of check valve. It should take 2-5 psi to open the valve. Could it be possible that one stuck open? Check them out. Info on them is on pg. 333 of the manual.

  10. #10
    will check it out and see...thanks

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