Outboard troubles

Discussion in 'Boats and Motors' started by bluebilldays, Jun 11, 2008.

  1. I have a 74 115hp Johnson outboard. I had alittle work done on it before the season started. The mechanic said that he adjusted the trottle screw and may need to be adjusted. While running in idle or slow speeds the outboard will sputter and sometimes die. It will start back up put will continue to do the same thing. If I turn the screw in it seems to run to fast(mph). She runs great at higher speeds. I do not care to take it back to the mechanic due to my temper and lack of time. If it is something simple I can and prefer to fix it myself. The engine never did this before. Fuel lines are new and also the tank. Thanks for any help or suggestions.
     
  2. Sounds like the air/fuel ratio is off. Miss adjusted! Not sure but Isnt the 115 a 2 cycle. Still it should have a mix adj screw. Maybe a low and high idle mix screw. If not your too rich or too lean at low idle and loose carbs and gaskets to make for rough idling. If everything looks tight(carbs) then look for a mix screw. If there isnt one it might mean the carbs are plugged. Still the same check for a GOOD spark by removing the plugs and grounding one out. Some Johnsons are known for weak coils. Theyll cut out on a low idle.
     

  3. Thanks. The plugs are new, and yes, it is a two cycle. I have been using the gas mixture the same for years with no problems. Would running the engine with some carb cleaner in the fuel be worth the time? Thanks again, I just need as many possiblilites as possible.
     
  4. get a can of seafoam and add it to your gas it will clean the fuel system and decarbon the engine,sometimes it will fix all your woes with the way it runs,it dont hurt to use extra,pull the plugs and put some in the cylinders and leave it sit over night then run the treated gas thru it,I usually run the recommended amount in the gas year around,it is also a fuel stabilizer,hope this helps you out,you can get seafoam at most automotive stores
     
  5. Shortly after I bought my 1st boat I went out & spent $30.00 to buy a Clymer's book on my engine. BEST BOAT INVESTMENT I EVER MADE!!! I've read in posts where someone writes they don't want to spend the $$$$ for the book. On the first thing I had to do to my motor I saved $300.00-$400.00!!! The seal at the prop was leaking, it told how to do it & what part I needed. I removed the cover & the Thrust Thingy, repacked the bearings, put in a new seal & put it back together. The actual repair cost me $23.00 for the seal. What would a shop charge to do that?? I always also ask on this forum & use the advise from the members, but having the exact procedure in front of me has been a tremendous $$ & time saver. It'll tell me if something is beyond what I can do. It saves huge amount of time & guess work to explain what could be causing whatever problem I'm having at the time. I have 17 bookmarks in it right now. I highly recommend getting off the $$ & saving 10 times it's cost. A good manual will tell exactly how to adjust whatever you have to adjust to fix your idle problem. Always ask on this forum also cuz that'll show you tricks that have helped me as much as the book has.
     
  6. buying a owner manual on the motor will be money well spent i also suggest that you get one also.....well worth the 30 dollars or so.....................Mike
     
  7. UFM82

    UFM82 The one others want to be

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    It ran OK before. The mechanic "adjusted" it and now it dies. Sounds like he did a great job. :confused:

    If you can ask him what he did maybe you can find out what's wrong. If the idle is set so low that the outboard dies, obviously you need to adjust the idle set screw. On a 115 that isn't like adjusting a set screw on your lawnmower. Or a weedeater. You'll have linkage there that the "mechanic" may have messed with. The manual idea is an outstanding one, especially for someone willing to try to figure it out themselves. You can save quite a bit of cash.

    You say it ran "too fast (mph)". What? Idling made the speed increase? Did you mean RPM? If a slight idle adjustment caused an excessively high idle speed and it was already idling too low, you could have a) one or more dirty carbs, b) one or more carbs out of sync, c) linkage issues. In any event, a manual will help you.

    UFM82

    Why did you take it to him in the first place? Was it doing something wrong?