What should I do first?

Discussion in 'Outboard Maintenance' started by Hdean, Jul 11, 2010.

  1. Hdean

    Hdean I Love microskiff.com!

    Hi All, Im a new user to the forum but have been using it for months to get ideas on what to buy.

    I'm looking for some advice and direction. I just bought a gheenoe and trailer from a local guy for what I think is a good deal. When I was about to leave his house he mentioned an outboard motor he wants to get rid of. It's an 8hp Johnson short shaft. It looks like it's probably from the 80's. We settled on $75 for it and he said the last time he used it was 7 years ago and it ran great then.

    So now that I have this thing and since I don't know the first thing about outboards I don't know what I should do to test it. Should I drain the gearbox and refill it with fresh oil? and should I spray some carburator cleaner in the carb? what do you all suggest.

  2. Brett

    Brett > PRO STAFF <

    Replace and set gap on new spark plugs.
    Check for spark, if spark continue...
    Start with a clean tank with a new 25 to 1 (gas/tcw3) 2 stroke oil mix.
    (treat it like a new motor, break in time all over again )
    Put the lower unit in a bucket of water (not flush muffs)
    Bucket of water only to check water pump if engine starts.
    Water level in bucket should be 1 inch over cavitation plate.
    Take the engine cover off!
    Hook up the fuel line, squeeze the bulb until it won't squeeze anymore,
    or...if gas starts to flow out of the carburetor.
    If gas flows out of the carb, stop!
    Time to rebuild the carb.
    If no leakage, try to start the engine with shifter in Neutral!
    Pull out the choke, set throttle to 1/4
    pull...if no start after 15 pulls remove plugs to see if fuel is entering piston chambers.
    After you've done all this, get back to us with the results...


  3. Hdean

    Hdean I Love microskiff.com!

    Ok, it took a while to a get around to do these tests.

    1) I pulled the plugs and check for spark - Spark was good
    2) Hooked up Fuel line and pumped ball until hard. No fuel came out the carb.
    3)Gave it a few pulls but nothing happened.
    4)Pulled plugs and there seemed to be a fuel smell in the cylinders. I added a shot of carb spray into each cylinder. Put the plugs back and gave it a pull. It cranked right up for about 2 seconds then stalled. did the carb spray in the cylinder once more and again it cranked right up then after 2 seconds stalled.

    It was getting late so I stoped for the night. My thoughts are that the two times it ran it was burning off the carb spray and not on fuel. Also, my fuel tank does not have fresh fuel in it, Could that be the problem? I would think it would run on older fuel, but just not well. :-/
  4. Swamp

    Swamp I Love microskiff.com!

    Pull carb, disassemble, and clean.  Make sure the float valve assembly functions well and that the main jet is totally free of varnish.   Try again.  If no joy, rebuild fuel pump, the gaskets get brittle with age and disuse especially if the fuel was not drained.  If you are not familiar with small engine carburetors, I suggest getting a service/repair manual.  That is a good investment anyway for when you discover the the water pump impeller probably did not like sitting for 7 years.  :-/  Sounds like you got a heck of a deal though.

    GET RID OF THE OLD FUEL!!!!! Do that first. Nothing good can come of using old 2 cycle mix. Got an old beat up lawn mower? Use it up in there, you can cut your grass and do skeeter control in one step. ;D
  5. Hdean

    Hdean I Love microskiff.com!

    Thanks. I'll pick up a manual for it online and great idea on that fuel mix. I dilute it down a bit for the 4cycle mower. Sketter controll lol. love it.

    I post my results.  :-?
  6. cutrunner

    cutrunner Cert. Yamaha technician

    if its been sitting that long i would change the waterpump impeller before you run it. ive seen it a hundred times where the blades dryrot and break off and get sucked into the powerhead cooling passages and you can never get them out. heed my warning
  7. Hdean

    Hdean I Love microskiff.com!

    Thanks Cut Runner, My original plan was to see if I could get it running before trying to tackle the water pump, but I had no idea about it getting sucked up and creating its own set of problems. Ill take your advice and do that and the carb together.

    Could anyone point me in the direction of where I should get parts from?

    I also order a Seloc repair manual for it.
  8. cutrunner

    cutrunner Cert. Yamaha technician

    always try to buy factory oem parts. some seirra parts are ok but dont use a sierra waterpump because the impellars have a brass insert in the rubber impeller that separates.
  9. cutrunner

    cutrunner Cert. Yamaha technician

    oh and be careful breaking all the gearcase and water pump bolts lose. if its an older saltwater used motor and the bolts have never been greased they will more than likely break. i would soak them with pb blaster for a day or two first and heat them with a torch before breaking them loose. it will save you alot of time in the end. especially if you dont have an easy out.
  10. Hdean

    Hdean I Love microskiff.com!

    Hi all, im in the middle of rebuilding the fuel pump and everything seems to be going smoothly (famous last words) but I noticed the fuel pump kit contains two diaphrams. Is the extra for a fuel pump that has two diaphrams our should I double these up?

    its a 1984 8hp Johnson
  11. Hdean

    Hdean I Love microskiff.com!

    Well the fuel pump is done. I paid close attention to how everything was possitioned when I took it off and made a video of most of the steps. maybe i'll post it on youtube and you all can give me pointer for future.

    Next up is the water pump iperller andthe carb.

    Is ther a  way to insert a picture of the boat project?
  12. noeettica

    noeettica Well-Known Member

    Check out the photo posting tips


    Photo bucket seems to work well
  13. Hdean

    Hdean I Love microskiff.com!

    Good Morning, lastnight I was able to sit down and reinstall the fuel pump i rebuilt along with the new water pump (housing & impeller)...

    Everything seemed to go smoothly, but there was one thing that I'm not sure about. While working the drive shaft slipped out of the lower unit which the manual said if this happens you have to open up the lower unit and re-insert it into the rack & pinion. But I didn't do that. I just pushed it back in to the lower unit.

    After I put everything back together I put the motor in forward and turned the fly wheel clockwise. The proped turned smoothly. Then I did the same test in neutral (the prop kind of turned but if I held it still while rotating the fly it quit turning. Then I put it in reverse and did the same test. The prop moved in the reverse direction. I think everything is working properly. Is that a fair assumption or is it possible the shaft is not properly seated in the pinion?

    My final item is the carb rebuild. To be honest I'm a bit intimidated to do this. Ive tried rebuilding carbs on my VW Bus and Jeep and it never turned out well. I called a few shops and they want $210 which seems kind of high. What I was wondering is if there is anyone on the forum who could help rebuild the carb and wouldn't mind teaching me along the way? I'd really like to learn instead of just pay a shop everytime.

    Again, thanks for all your advice. I'm thrilled that this resource is here.
  14. cutrunner

    cutrunner Cert. Yamaha technician

    Im a cert. Yamaha tech, im about an hour north of you, i wouldnt mind teachin you if you spotted me gas money :)
  15. Frank_Sebastian

    Frank_Sebastian Well-Known Member

    Hi Mr Dean,

    I like the engine you have. Be patient and get things right and it will be a very good match for your boat.

    In regard to the shaft pulling out of the lower unit. You will likely have a problem with the shaft seal if you just stick it back together. There is at least an "O" ring that the shaft fits into. The shaft must be very smooth in this area and the bushing/bearing right below it. While it is apart I would replace the seal.

    The carburetor on that engine is almost the same for 4 HP to 20 HP engines and very easy to work on. Study the job on this one.   http://www.marineenginedigest.com/diy/carb.htm

    Get the kit and follow the instructions. If you haven't used automotive carb cleaners before, then buy a gallon of Yamaha (OMC will do) engine tuner. It will cost about $40, but you can soak the carb for a day or two if needed. You will need a bull nosed punch with a 1/4" or 5/16 end to set the plugs in the low speed circuit. The kit will come with instructions, but it is a good idea to make sure it does as sometimes the dealer orders them in factory packs that come without any info enclosed.

    Best regards,
  16. Frank_Sebastian

    Frank_Sebastian Well-Known Member

    Let me add this. The freeze plug does not need a sealer nowadays. Don't know why, but I have been told this by too many techs for it to be false.

  17. CaptainRob

    CaptainRob Hell's Bay 17.8 Whipray

    I just rebuilt the carb on an old 18 merc. It was the first time I tried to do any type of mechanical work on an engine and I can tell you, do the carb yourself. Once you get in there(take your time), you will see it is a pretty basic job. Take everything appart carefully and just make sure you look at a good schematic to make sure it all goes back together. Otherwise, its a pretty simple process. I actually used a schematic I found online and that was easily enough to help me get everything back correctly.
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