Yamaha 9.9 4stroke burning oil

Discussion in 'Outboard Maintenance' started by pullonofhhi, Sep 20, 2009.

  1. pullonofhhi

    pullonofhhi No Barlownians!

    I have a 9.9 2002 yamaha 4 stroke that was laid down on the carb side. Oil got into the carb and I cleaned it all out and got it running, but it smokes now like hell.

    I took it to a yamaha service rep and he said it runs fine and all I have to do is run the hell out of it. Well I have been running it but it is using waaaayy too much oil ( about a pint for every hour or 2 of run time).

    Any suggestions or anyone with a similiar problem?

  2. Brett

    Brett > PRO STAFF <

    As a guess I'd say oil is being pulled out of the crankcase by the scavenger tube,
    or you're overfilling the oil level past where it needs to be.

    oil capacity pdf link:


    Looks like total capacity for a 2002 9.9 is 1 quart.

  3. pullonofhhi

    pullonofhhi No Barlownians!

    Why would it be pulled out of the scavenger tube? and how can I stop it.

    I fill it to capacity, then run it for an hour or 2 @ full throttle and its about a pint low, so I dont think I am over capacity.
  4. noeettica

    noeettica Well-Known Member

    Sounds like some small part is clogged up or somthing stuck ... Probibly will fix It's Self ... That motor is very hard to dammage ...

    Or ... Not sure if the rings are Pinned or not the gaps may be Lined up

    Carefully pull the oil cap and see how much blow-by you have ...

    I still can't Immagine a problem these are very Well made Motors !!!

  5. Brett

    Brett > PRO STAFF <

    Your tech said the engine's running fine, and the only other spot I know of
    that can pull that much oil is the crankcase gas scavenger tube.

    To check your dipstick is showing the right level,
    drain the block, then put only 1 quart back in.
    Verify the oil mark on the dipstick.

    The 9.9 yami has an oil separator as part of the scavenger tube
    to intake manifold, that could be what is messed up.
    View the intake portion of the parts diagram to see the assembly.


    My best guess without having hands on.
  6. pullonofhhi

    pullonofhhi No Barlownians!

    Thanks for the suggestions, I am going to get a look @ it and see.

    What ya'll are saying jybes with what others have been telling me also, I just can't get it figured out.

    That's what gets me, beside the oil burning the thing is running strong and starting with little or no effort.
  7. pullonofhhi

    pullonofhhi No Barlownians!

    Well, I drained the oil and added only 1 quart. Then ran it. There is oil coming up the scavenger tube and for the first time I noticed a knocking sound and lots more smoke.

    Look like at best I have a stuck valve of some sort, @ worst worn or blown engine.

    I am going to get the manual for this motor and tear it down and figure it out one way or another.

    Thanks for all the feedback.