Reply To: Hard to start HA 10 Johnson (1940) 2.5hp

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November 21, 2021 at 8:29 am #249980
Buccaneer
Participant

    US Member

    I just looked at the notes on my HA-10, that I went through a few years ago.
    It had 66 & 68 psi compression. I have video proof that it run, but it
    would not idle down without dying. I’m not sure if I was able to rope start it,
    or if I used a drill.

    It seems that the smaller the bore engine you have, the higher compression
    you need. I’m not sure what these engines had for compression new, but
    guessing at least 75 psi.

    Not sure what the “plunger seals” are that you refer to?

    Prepare to be boarded!