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  1. M

    1977 Johnson 70 Horse Salvageable?

    Ok so I finally broke down and split the case on my 1977 Johnson 70 horse as some of you already advised. I was redoing the exhaust manifold gaskets and found rusty water in the exhaust ports and I could see the scored pistons so I tore it down. It doesn't look pretty to me but it's been a long...
  2. M

    My 1977 Johnson 70 Horse Struggles All Combined

    I am tearing the whole engine down. The head was straight before when I had it off but I will check it again. If I repair the engine I will assume it is warped and resurface it anyway.
  3. M

    My 1977 Johnson 70 Horse Struggles All Combined

    I need to apologize to Racerone and F_R. You guys were totally right about the engine having internal issues. I was stubborn, acted like an ass and made a fool out of myself. I should have listened to you guys from the start. I found a parts motor for $100. I pulled the exhaust manifold/plates...
  4. M

    My 1977 Johnson 70 Horse Struggles All Combined

    The first told me to throw away the motor and buy a new one without actually even attempting to get down to what the problem is. The second basicly told me I was an idiot and to go buy a 4 stroke that can do all the thinking for me. It doesn't really feel like a loss to me for some odd reason...
  5. M

    My 1977 Johnson 70 Horse Struggles All Combined

    It's 120ish PSI COLD. You're going to sit here and tell me compression is 100% the entire problem? We are going to have to agree to disagree. There are no plastic bearing cages inside of the engine that I am aware of. No lateral movement of the flywheel and the piston pins feel tight. Have I...
  6. M

    My 1977 Johnson 70 Horse Struggles All Combined

    What in particular should I be spending them on? It sure isn't beer. LOL
  7. M

    My 1977 Johnson 70 Horse Struggles All Combined

    Yeah, IDK, around the intake ports between the carb plate and the reed assembly they were soaked and I could smear the gasket material with a finger. I am very stubborn when it comes to stuff like this. I won't quit until I find what exactly is causing my issues and determine it to be...
  8. M

    My 1977 Johnson 70 Horse Struggles All Combined

    You may be right. I just don't like to be defeated until I know without a doubt I am defeated you know? At the least I'd like to know why I am defeated. I looked at the pistons through the exhaust ports though and they looked good. The cylinders looked good too. No scoring at all. I suppose...
  9. M

    Runs great wide Open but hard to get it there

    I made a new post that summarizes everything that I have fixed and found wrong with this engine. I describe the overheating and compression tests there. 120 isn't terrible for a 43 year old engine. I really don't feel like compression is my main issue.
  10. M

    My 1977 Johnson 70 Horse Struggles All Combined

    I have made a few different threads about various stages of my struggle with my boat motor. I made this post to compile all of the information together and hopefully get this figured out (like the on-my-knees-begging kind of hopefully). Ok, this post is going to be a long one so buckle up. If...
  11. M

    Runs great wide Open but hard to get it there

    Yes, I checked all three cylinders with a gap spark tester and all three jumped a 7/16" gap.
  12. M

    Runs great wide Open but hard to get it there

    Ok so here’s an update…. I took the boat up north but the day before I left I bought three new coils and swapped them out. The old coils tested way out of spec or didn’t test at all. I also was spraying carb cleaner around my intake manifold gasket with the engine idling “smoothly” and the motor...
  13. M

    Am I testing my coils correctly?

    They are removed from the engine.
  14. M

    Runs great wide Open but hard to get it there

    I don't have one :unsure:
  15. M

    Runs great wide Open but hard to get it there

    I read up some more on the testing and I am 99% positive I was doing it right. I took all three coils off. Put the black test lead on the coil ground wire and the red inside the spark plug socket and got no reading on one and the funky reading on the other.
  16. M

    Runs great wide Open but hard to get it there

    I don't feel as much of an idiot now. Thank you for that LOL. Do you think my whole problem today was 2 bad coils at lower RPM's and the funky coil kicked in at higher RPM's when it ran good?
  17. M

    Am I testing my coils correctly?

    I just duplicated the tests with a second multimeter. So either I am doing something wrong or my boat was running great today at WOT ON ONE CYLINDER that even had an out of spec coil.
  18. M

    Am I testing my coils correctly?

    I took all three coils off and the results are exactly the same as listed above. How is this possible? It ran and idled pretty good in the garage on muffs. I took it to the lake today and it ran like crap at low rpm but ran great at WOT.
  19. M

    Am I testing my coils correctly?

    Edit: I have a 1977 Johnson 70 horse. When I had it running on muffs in the garage earlier the engine bogged on every cylinder when I pulled the plug wire. That tells me the engine was firing on all three cylinders. I was just checking my coils with a multimeter. I set my multimeter to the 20...
  20. M

    Runs great wide Open but hard to get it there

    Also, I was just checking my coils with a multimeter. I set my multimeter to the 20 ohms range to check the primary's. They all tested at 0.4 ohms which from what I read should be 0.2-1.0 making the primary circuit good. Next I tested the secondary or output circuit of the coil and that's where...
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