Merc 2-stroke oil pump maintenance

Discussion in 'Outboard Maintenance' started by Dillusion, Dec 16, 2014.

  1. Dillusion

    Dillusion devilray snob

    Cut/creek et al;

    What maintenance/checks can be done on the old 1999-2005 merc 2-stroke 40/50/60 outboards oil injection pumps?

    I've read that sometimes the oil pump can sometimes just stop working unbeknownst to the operator and just fry the block with no warning.

    My '99 has been running 100% and I dont know if anything was ever done to the oil system.

    Is it just one of those things where it's like..."oh well, time for a new motor!" if it goes out?

    I know you can switch to pre-mix to avoid this but that defeats the purpose of having an 'advanced' motor...if I wanted to do pre-mix I would buy a barebones 25.
  2. bw510

    bw510 I Love!

    Good question.
    I'm curious about this as well on my 90 merc

  3. spottail1588

    spottail1588 I Love!

    Premix and have no worries
  4. GSSF

    GSSF I love my microskiff

    I disabled my injection system three years ago. I have a 2001 Mercury 90 2 stroke. I went to pre-mix and never looked back. 
  5. Dillusion

    Dillusion devilray snob

    Not the answer I was looking for but thanks. Pre-mixing defeats the purpose of owning a motor with advanced features...

    I guess there's nothing that can be done to the oil system as maintenance :(
  6. Creek Runner

    Creek Runner Well-Known Member

    Matty, other than an inspection and oil drip test nothing can be done. The issue with the oil pumps was really on the earlier models, they had a nylon gear on the crank shaft and a metal gear on the oil pump rod, over time the nylon gear would strip.

    The newer Model enignes 2000's had far fewer issues.

  7. spottail1588

    spottail1588 I Love!

    What is advanced about oil injection?
  8. cutrunner

    cutrunner Cert. Yamaha technician

    What creek said, he bronze gear setups are almost bulletproof. The only other thing that can cause an issue is frequently mixing different brand 2 stroke oils.

    The benefit of oil injection is reduced oil consumption, cleaner burning.
  9. Dillusion

    Dillusion devilray snob

    So if I'm a 99 I probably have the bronze/metal gear pump parts? As long as I have the 'newer' iteration model of the 3cyl motor that started in 1999.5ish?

    Also what is this 'oil drip test' I don't see any reference to it in the service manual.
  10. cutrunner

    cutrunner Cert. Yamaha technician

    That is a question for Creek, i dont do Mercs, he does. So i dont onow any specifics on your motor