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O/T Johnson Sea Horse Tune-Up Advice?

Discussion in 'Off Topic Threads' started by GW22, Jul 12, 2009.

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  1. GW22

    GW22 Active Member

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    Can anyone help advise me on tuning-up an old Johnson 9.5 HP Sea Horse motor that's coming with a bass boat I'm buying today? I can't find a decent free forum on the subject.

    It's a 2-Stroke, 2-Cyl., around late 60s vintage and I need to work on it sooner that I can get a manual. It hasn't run in 2-3 years. It started on the tenth pull even with 3-year old gas/oil, but smoked quite a bit. What are the first things to do in order to get it running well and be able to use it soon w/o damaging it? New plugs? Carb cleaner? Oil change? Some kind of gear/shaft oil?

    The owner said the only problem is a pull-cord issue that "everyone knows about." He didn't explain it too well, but the flywheel is slotted for direct rope hook-up, so at least I woon't get stranded if the cord pulls out.

    I'm mechanically inclined but have very limited experience w/ boat motors, so any help would be most appreciated.

    -Gary
     
  2. Shooting Jack

    Shooting Jack Active Member

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    It's normal for it to smoke as the fuel mixture is 35 to 1 on the older motors. New plugs is a good idea and get some B12 from your local auto parts place and put in the gas/oil mixture and it will clean the carburator better than Seafoam. If it's firing good I would skip the points as they are under the flywheel which has to be removed to replace them. New fuel will make a lot of difference as unleaded fuel starts losing it potency in just 90 days. I probably have several books on the motor so if there is a specific question email me and I will try to answer it. Jackie B.
     
  3. Carol Lister

    Carol Lister TS Member

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  4. GW22

    GW22 Active Member

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    Thanks for your reply, Shooting Jack. You said you have several books on this motor, so I assume you know it pretty well? Is it a decent motor? Is it reasonable to expect a few more years of decent service from it after 40 years if the thing has been taken care of? I don't want to start putting money into it if it's likely that I'll need to upgrade soon anyway.

    Thanks again,
    Gary
     
  5. GW22

    GW22 Active Member

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    Thanks Carol.

    -Gary
     
  6. Tron

    Tron Supporting Vendor Supporting Vendor

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    I would start by checking the spark. You want a nice strong blue and not a yellow spark. Condensors and coils do not last forever and if they are original, replace them and save yourself from being stranded on the far side of some lake. They are cheap and simple to replace (along with the plugs and points) and you'll be good to go for years. I'd also save yourself a headache down the road and go ahead with a fuel pump kit and carb kit.....also cheap and easy insurance. While you're at it, replace the fuel lines and fitting O rings.

    Be sure that the motor is spitting out water when running and that the lower unit oil is clean and not have a milky hue to it.

    Just some things to consider.
     
  7. Tron

    Tron Supporting Vendor Supporting Vendor

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    OH, and another thing: always be careful about the history of these engines in this horsepower range. They were the standard issue as a rental unit(Johnson/Evinrude had the rental market hands down)...something that you don't want to be stuck with.
     
  8. Carol Lister

    Carol Lister TS Member

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    Modern gasoline containing ethanol is not kind to 2-cycle engines or their internal seals. Try to locate a source of ethanol-free gasoline if you can. Do NOT be tempted to add addition oil to the mix to offset the effects of the alcohol. This will alter the air-fuel ratio. It is also possible that the engine is already jetted to accommodate a 20- or 30:1 oil-fuel mix. This will mean an improper air-fuel ration if it's fed a diet of modern 50:1 fuel.

    Carol Lister
     
  9. GW22

    GW22 Active Member

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    If the lower unit water is milky, is it a simple O-ring or gasket change or will it take major surgery? Must it be done immediately or can the oil be changed and the real fix be done later?

    Someone also suggested installing a new water pump impeller. If the motor is spitting water steadily, is this necessary or should I just wait till the off-season? Any idea if that's a quick/easy job or if it's hard to access?

    -Gary
     
  10. Tron

    Tron Supporting Vendor Supporting Vendor

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    Simplicity is a relative term that depends on your mechanical ability. Something that may be very easy to me, may be very difficult for you. Something that you find simple, I may have a hard time with.

    There are about 6 or 7 seals that come in a lower unit kit. That particular engine has 2 seals at the output shaft, one large O ring at the housing, 2 at the water pump shaft and one at the shift linkage. Usually, the output shaft (that your prop mounts on) leaks due to fishing line ripping up the seals....but, at that age, any of them could leak. It's something that MUST be taken care of and CAN NOT wait. The gears and bearing cost way more than the engine is worth, so take care of that.

    Chances are the impeller has been changed at least once or twice over the years, so if it's spitting out water, I wouldn't mess with it unless you're in there already with other repairs.
     
  11. Tron

    Tron Supporting Vendor Supporting Vendor

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    Yeah, good point EE....good insurance.
     
  12. GW22

    GW22 Active Member

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    As mentioned, I don't have much experience w/ boat motors, but I'm fine handling most mechanical/engine repairs if I have the right info and/or manual. So I appreciate everyone's advice. I'll take a closer look later today when I get my hands on the motor.

    Oh yeah -- I suspect that the crankcase does not have separate oil, correct? Do the crank journals and rod ends use needle bearings which get lubricated by the oil mixed in the gas?

    Thanks again,

    Gary
     
  13. Tron

    Tron Supporting Vendor Supporting Vendor

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    It's a 2 stroke. No oil in the crankcase. No needle bearings on crank journals and yes, the moving parts are lubricated by the gas/oil mixture.
     
  14. Damifino

    Damifino Member

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    Try posting on www.thehulltruth.com - They know everything about boats and motors.
     
  15. GW22

    GW22 Active Member

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    Does anyone happen to know the correct spark plug number (preferably Champion) and official gas/oil mix ratio? I've been told 35:1, 40:1 and 50:1. I suppose I could go with 40:1 and call it a day, but if anyone has the mfr's recommendation I'd appreciate knowing what it is.

    Thank you,
    Gary
     
  16. Quack Shot

    Quack Shot Active Member

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    Tron,

    What kind of bearings would that motor have if not needle/roller caged bearings? It's been a long while since I've had something that old and that small apeart, but the crank bearings I remember were indeed roller/needle style.

    Using a decent 2 cycle oil, you'd probably do fine at 40:1 or even 50:1. Depending on when it was manufactured, it could be a 50:1 motor. 50:1 came about in the mid sixties, if my memory is still working. They had a new reformulated oil that helped make that possible.

    Sometimes the hardest part is getting them apart without breaking screws and bolts. If it's EVER been in Salt or Brackish water, you may have a challenge on your hands. If it's working for now, do as little as you can to make it work for now. Do what you can later on when you aren't pressed for time. Check it out thoroughly and save the hard stuff for later. Anything like the lower unit or cooling NEEDS to be addressed. Optional stuff might be another story. Get a manual and parts list for it.
     
  17. Carol Lister

    Carol Lister TS Member

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  18. GW22

    GW22 Active Member

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    Just wanted to say THANK YOU again to all who helped. The motor is running and I've located most of the parts I need to finish tuning it up.

    -Gary
     
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