76 merc 20hp wont start

Discussion in 'Bubba's Outboards' started by miichael, Nov 15, 2006.

  1. miichael

    miichael New Member

    Messages:
    380
    State:
    North Carolina
    I got a 1976 mercury 20hp model 200 and it was running OK, idled rough but didn't miss at full throttle. now its got to where it just wont start. I try to pull it and it puffs out the exhaust and through carb and it jerks the rope back into the starter almost ripping your fingers off. It starts to crank every now and then but just dies out fast not running for more than 2-3 seconds. The way its jerking the starter rope back acts like it may be out of time but im not sure. I do have a repair manual but i was wanting to get some ideas to where to start looking. I put new plugs they are both firing great on both cylinders but it just wont start. Is it a carb issue making it do this? or a timing? any info be great.
     
  2. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Michael it sounds like it is putting to much fuel into the cylinders and that is why you are getting the rebound on the starter rope. If you are getting good spark and then do me a compression ck and post the numbers. This will tell me things I need to know. It is possible that it has sheared the woodruff key in the fly wheel.
    I would unhook the fuel line and take the plugs out and pull her until all the fuel is out. Then take a squirt bottle with fuel mix and spray a little into the carb throat and see if it will crank.
    I have seen diaphragms on fuel pumps get a hole in them and act like this but that is a long shot.
     

  3. miichael

    miichael New Member

    Messages:
    380
    State:
    North Carolina
    i will get you compression results tomorrow. i may go ahead and take the carb off and give it a good cleaning. just wasn't sure it would have that rebound if it was a carb problem. ill let you know tomorrow the results.
     
  4. miichael

    miichael New Member

    Messages:
    380
    State:
    North Carolina
    ok did a compression check top cyl 95psi and bottom cyl 98psi on pull start. i was pumping the bulb and then i noticed gas come out of overflow from bowl so then i knew the needle and seat was prob sticking. i took carb off and cleaned good and put it back on and she fire up but was like missing every now and then. it would would run then miss then run and miss a time. i adjusted on the air screw and got it where it wasn't missing and it idles now when you turn it all way down to shift on muffs. is there a setting for the air screw on carb? i know most non outboards are screw all way in back out 1 1/4 turns. is this rule same for outboards? thanks alot for the help.

    and also im using evinrude johnson oil to mix is that ok or should i be using mercury oil? i just been using the evinrude oil because thats what my other boat takes, thanks
     
  5. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Yea that oil is okay for the mix. If you ever run out just go to wal-mart and get you a gal of super tech it was tested and proven to be as good or better then name brand oils. I use it all the time.

    You need to get you a rebuild kit and soak that carb and rebuild it. The skiping is most likely coming from the low idle pick up and adjusting the screw out compansates for that. Goes to the lean side a bit so you have to richen it up. Most idle screws do set like you did but I put mine in gear to adjust them and this gives me some what of a high idle at netural but you can adjust that down on the side of the motor. I like mine to idle at about 11 to 1200. That compression is great this tells me it has good ring seal and do a decarb on it and you will notice that the idle will get smoother.
     
  6. miichael

    miichael New Member

    Messages:
    380
    State:
    North Carolina
    i did a decarb in it a while back using evinrude decarb and it did help it out then. im going to get me a carb rebuild kit and rebuild the carb. so do you think if i rebuild it it will take the skipping out? im going to order the kit today prob be here next week but im wanting to take the boat out in morning to go deer hunting. i use the boat to go up the river and hunt backside of the land. do you think it will be ok for now to run it like it is? i go upriver so if it does quit on me i can troll back down. thanks for the help

    will this kit work? says fits 6443973-Up but mine starts with like 445

    http://iboats.com/mall/partfinder/c...d_poid.112207/gd_row.24/session_id.115594330/
     
  7. miichael

    miichael New Member

    Messages:
    380
    State:
    North Carolina
    my serial number is 4409457
     
  8. 18lbflathead

    18lbflathead New Member

    Messages:
    21
    State:
    Ohio
    The Pistons are miss firing which caused the carborator to go out you need new pistons and a new carborator.Let me know if u have any more trouble with a car,motorcycle or any other thing.:smile2:
     
  9. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Michael if you have the WMA carbs that should work it will fit most late model carbs. The previous carb used on that engine was a BA or AB carb which had the drop down bowl.

    As for running it a short while If its not missing constantly then I wouldn't be afraid to run it a short while.

    Oh BTW I can get you that carb kit at a little less cost and shipping if you want it or you can go to any ORielly auto parts store and most time have next day or withen 2 days.
    Just use the sierra parts number 18-7212
     
  10. miichael

    miichael New Member

    Messages:
    380
    State:
    North Carolina
    I didnt know you could get marine parts from a autoparts store? can i go to auto zone or advance auto and have them order it also?
     
  11. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Orilleys and napa are the only ones I am familiar with that does this
     
  12. miichael

    miichael New Member

    Messages:
    380
    State:
    North Carolina
    My carb is is BA - 20. that the right kit? the 18-7212
     
  13. miichael

    miichael New Member

    Messages:
    380
    State:
    North Carolina
    Some the stuff looks different in that sierra kit i dont think it is the right one. i found the kit at this website and it looks a lot different.

    http://www.ishopmarine.com at top put in search for this part # MM-139951991

    that's for my carb there. its got the round bowl gasket where the sierra has a squared end instead of round.
     
  14. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Your motor must have been made in the latter part of the previous year then because if it is a BA carb then it won't fit.
    must be the 18-7013 then
     
  15. miichael

    miichael New Member

    Messages:
    380
    State:
    North Carolina
    that one doesnt look like it either. its got the 7/16 drain plug that holds the bowl on. the bowl is round all but one part then it like U's inward.
     
  16. miichael

    miichael New Member

    Messages:
    380
    State:
    North Carolina
    oldmercs.com has it here.

    http://www.oldmercs.com/1399-5199-1.gif

    that bottom seal with the U part on it with that round gasket laying inside it is my bowl design.

    1399-5199-1 Carburetor Rebuild Kit from Mercury fits 20HP models 1973 thru 1980, and 4-cyl. 50HP 1976 thru 1981. $52.70
     
  17. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Michael that serial number matches up to a model 110 --11 h/p

    Double ck that serial number and see if it has a letter in front of it like a B or something.

    Did you buy this motor used if you did then some one may have changed the transom mount or the cowling on it.

    Now has the carb got a large round bowl on the bottom or a small long bowl hanging off to the left side slightly.
     
  18. miichael

    miichael New Member

    Messages:
    380
    State:
    North Carolina
    let me run outside and look again ill let you know what the whole number is.
     
  19. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    now that is begining to make sense hang on a min and I'll see if I can hook you up with a better price
     
  20. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill