Bad Test Equipment

Discussion in 'Outboard Maintenance' started by MariettaMike, Sep 6, 2014.

  1. MariettaMike

    MariettaMike Wish'n I was Fish'n!

    For no particular reason I picked up a free rental compression tester at AutoZone while I was there for some other stuff on Thursday. Pulled plugs, put the tester on top, gave it a spin. EIGHTY! middle SEVENTY-FIVE! bottom SEVENTY-SEVEN

    After 48 anxious hours I tested it again with a different gauge at the Yamaha dealer and found 118T-110M-118B

    Lesson Learned: Don't trust free diagnostic test equipment from a place that only sells parts.
  2. cutrunner

    cutrunner Cert. Yamaha technician

    There wasnt really anything wrong with the guage technically. Im sure it was very used and probably dropped a few times.... but it still gave readings within 10percent of each other. Also EVERY guage is different, and ive proven that to my snap on guy by taking 2 brand new guages off his shelf and testing the same motor back to back.
    also you need to be checking your compression on a warm, just ran motor for more accurate results

  3. priscillatgorilla

    priscillatgorilla I Love!


    true !

    you're looking for uniformity - "specs" are often misleading

    compression tester results will vary