Need help with my boat motor

Discussion in 'Bubba's Outboards' started by etipriga, Feb 28, 2006.

  1. etipriga

    etipriga New Member

    Messages:
    96
    State:
    TX
    I got a 1978 Johnson 25 horse and I could really use some info from u guys. A while back i took the lower unit off and when i put it back on i missed the hole that the water pump hose connects to the motor. So im riding down the river and all of a sudden the motor shuts off. I turn around and theres smoke coming off the motor. Well stupid me instead of paddling back i just decided to crank it up and splash water on the motor till i got back.

    So i got back to the boat ramp and everything seemed ok. After i got home and took the lower unit off again i aligned the hose where it was supposed to be. I took it out a few days later and cranked it up like normal and started down the river again, then it just cut off. I went home and i believe i changed the spark plugs to get it running again. So i took it out yet again and the same thing happened. After it happened both times i couldnt get it started again. The motor was prolly not running for about five minutes both times before it cut off. And it didnt sputter or ne thing it just cut off and that was it.

    So im just trying to figure out whats wrong with this thing and if it can be fixed.
    Any info you fellas got will be very helpful, thanks.
     
  2. beeheck

    beeheck New Member

    Messages:
    631
    State:
    Iowa / Missouri
    I'm not a mechanic but I would ask, are you sure you have oil in the gas? My sons mowed my lawn with my 2 cyl lawn mower without oil and it would run and die start back up, run for a couple minutes and then die. Put in the right mix and it ran fine until they forgot the oil weeks later again and it did the same thing. Might just be sure you have the right oil mix or even just oil at all in the gas. Still using that lawn mower about 6 years later but I wouldn't want to see the piston or cylinder wall.
    Second thing is the fuel hose, primer bulb and tank/motor connectors. Any leak in these will shut a motor down quick. We found that out on the river late one night and then it was a pain to start. We got home by squeezing the primer bulb all the way back.
    Fuel pump, I had a fuel pump with a cracked diaphragm and it would run fine until it warmed up and then it would shut down due to the crack. Don't know why or how it ran when it was cold but it did.
    Biggest problem I can see is the smoke coming off the engine. Not a good thing so obviously overheated. What a motor will due when the cylinder wall and piston have become scored is run until it heats up and then keeps heating up and then seizes up do to excessive friction. If I had to bet this is the one I would bet on. But I'm sure there are more mechanically inclined people than me that will have ideas and I would listen to them first.
     

  3. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Next time it shuts down on you take the plugs out and see if they are wet.
    If they are then you either blew a gasket or warped a head.

    I would do a compression ck and see what that is and change the gaskets out because when one of those engines get that hot it has a tendencey to swell every thing in it.

    While you have the head cover off ck the walls for scoring.
     
  4. etipriga

    etipriga New Member

    Messages:
    96
    State:
    TX
    The oil mixture is right and all of the hoses look like they are ok. I will be going home around the 11th so i will try and crank it then and see what happens, then ill check back in. Thanks for the help!!

    and i forgot to ask what should the compression be at on this motor?
     
  5. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    It ain't as much compression you have its how even they are. If it is say a hundred and up and each cylinder is within 10 to 15 % of each other then you would be good to go. I have seen them run with an even 70 pounds on each cylinder but when it gets that low it makes them hard to start.
     
  6. rockk

    rockk New Member

    Messages:
    16
    State:
    E.C,florida
    head gasket water jacket spraying on top of piston
     
  7. NCBASSIN

    NCBASSIN New Member

    Messages:
    63
    State:
    North Carolina
    I would have to go with head gasket or head as well . I have had the same problem on a 25 Evinrude and ended up having to buy another head for it cause where it had been used in salt water so much it had eat the head up and was letting water get over on the piston. I went to a boat repair shop and bought a used head for like 40 dollars and it was good as new . good luck ............Danny
     
  8. zappaf19

    zappaf19 New Member

    Messages:
    1,574
    State:
    Monticello,IN
    Oh man not good. Do the compression check! Can you see water coming out of the head when it is running?
    Bill
     
  9. etipriga

    etipriga New Member

    Messages:
    96
    State:
    TX
    Whenever the motor is runnig everything looks normal from the outside(no leaks that i can see).
     
  10. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Most likely not go to the outside. It will go into the cylinder and exit from the exhaust and when the cylinder fill up and plug quits fireing, it hydro locks. Hence a shut down and seize up.

    If not fixed could result in a complete power head failure.
     
  11. etipriga

    etipriga New Member

    Messages:
    96
    State:
    TX
    I also forgot to ask u guys; should i buy a compression tester or just take the motor in, and how much would it cost. Thanks.
     
  12. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    If you are gonna keep useing outboards I would buy a good tester. That is one of the first things I use when trouble shooting. Get one that will screw in not the kind with the rubber tip. If you have a autozone store close by you can rent one.
     
  13. Snobal

    Snobal New Member

    Messages:
    40
    State:
    Canton, OH
    The Autozone by me has them for about $27. Everytime I rent something from them I get the junk that someone else rented, destroyed, and returned. I guess the guys at Zone don't check the returns very well or just plain don't know what they are looking for when it comes to damage. I guess if you don't know how to use a tool you probly don't know what "broken" looks like.

    If you plan on needing a tool that they rent more than one time, I would advise just buying a new one. Usually the rental fee is the same as the tool would cost new except if you rent it you will get the money back when you return it.
     
  14. etipriga

    etipriga New Member

    Messages:
    96
    State:
    TX
    Well guys i will be going home on the 11th so ill check over all of the stuff u guys mentioned. Once i look over it all ill give yall an update.

    Thanks for all the help!!!!:worship:
     
  15. etipriga

    etipriga New Member

    Messages:
    96
    State:
    TX
    I dont know if yall have read my other thread but i ended up buying a 1972 25 horse for fifty bucks for parts then i ended up fixing it. i didnt take ne parts off the motor i have been telling yall about so now i got 1 that runs good and ill guess i might still try to fix this other one. Thanks again for all the help!!