Rebuilding Carbs?

Discussion in 'Boat Repair Help' started by jgdishon, Aug 10, 2006.

  1. jgdishon

    jgdishon New Member

    Messages:
    62
    State:
    Snowville,Virgi
    I have a 1986 Mecury 50 HP that I bought used and runs like crap. The guy I bought it off of said it ran great when he took it off the water 2 years ago. I have cleaned the carbs, pumps, needle valves with spray carb cleaner and it still has this problem. It starts and idel's fine, but when I put it in gear and give it gas it goes from idel to wide open, no in between. When running wide open it will get my 16 foot fiberglass tri hull up to about 15 MPH not enough to get up on plain, it also hesitates for a split second then picks back up like it has dirt passing through it. It does'nt though because i have changed the bulb the lines the tank and the gas. I think I need to rebuild the two WMA one barrel carbs. Does anyone have expirience with this? Is there anything I need to be careful of? Any help greatly appreciated. I've already ordered the kits.
     
  2. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    You need to take them apart and soak them for about three hours before you try to rebuild them. The float has a little spring sticking up out of the top so don;t try to adjust that spring. Did you check the fuel pump before you start to rebuild the carbs. Sometimes the old diaphragms would have a pin hole in them and make it run bad.

    You also want to take some compressed air and blow out every little hole and crevice in those carbs.
     

  3. jgdishon

    jgdishon New Member

    Messages:
    62
    State:
    Snowville,Virgi
    I did not take the pumps apart as the disk and gaskets were stuck together. I did clean the screen and sprayed cleaner down inside the holes under it. Also I did remove the float and took the needle valve out and sprayed cleaner inside of it and cleaned the needle. I did not mess with the spring at all. Are there any springs or anything between the disk and gaskets that make up the pump?
     
  4. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    If you are talking about the fuel pump on the side yes I do think there is a spring located in it. I never rebuild those I just replace them. As for the carbs you need to completely dissemble them and soak them or you are throwing your money away. There are a lot of crevices where that scum from demerited gas can hide.
     
  5. jgdishon

    jgdishon New Member

    Messages:
    62
    State:
    Snowville,Virgi
    What should I soak them in?
     
  6. AwShucks

    AwShucks New Member

    Messages:
    4,532
    State:
    Guthrie, Oklaho
    Jeff, the fuel pump normally has two smallish springs and a diaphram. They are SOB's in they must be reassembled the right way. If your going to go to the trouble of messing with your carbs, I'd do like bubbakat says. Get a rebuild kit for each carb. One at a time dissassemble them, soak them, clean them, then clean them some more. Use compressed air to blow out the orfices and lines. Reassemble them paying strict attention to any distance measurements the instructions give. Set the completed carb to the side and repeat this process for each carb. Use carb cleaner from any auto parts store or Wal-mart. Another helpful tip is to replace all those fuel lines while you have the carbs apart and soaking. They may look new, but they may have enough pin holes in them to sink the Titanic. Think the most your talking about on the fuel lines is about $3.00. Don't use the metal hose clamps either. Tighten them to tight and your gonna need a new fuel pump/carb. Use plastic wire ties from an auto parts store or wal-marts. Then, ask Bubbakat why the darn things still won't work. Think there is a sticky at the top of the motor repair help section concerning rebuilding the carbs. Follow it. Don't get in a hurry and do the job half way.
     
  7. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Lawarence you write a good line man.:lol:

    You can buy a gal of berryman carb cleaner with the basket and all at auto zone for about 16 bucks.
    And lawarence told you righ with his post. Clean and then clean again. Those things are hard enough to take off of a merc the first time let alone take off the second go around. If you need some blow ups of the carbs just holler out.
     
  8. AwShucks

    AwShucks New Member

    Messages:
    4,532
    State:
    Guthrie, Oklaho
    My buddy, Fuzzface, just rebuilt the three carbs on his 70 HP Evinrude. He did it one at a time as I said above. Kept them in the right order and put them back on. Got about 1/4 mile from the shore and it dies. Dead. Lot of paddling against the wind - and it blows in Oklahoma. Got the boat home, looked at all the stuff again. Went to another guy who works on his motors and he said that the carbs were put back on in the wrong order. Bottom carb had a fuel line which kept getting crimped. The problem was the previous owner had taken the carbs apart and when he reassembled them he put the body of the second carb on the 3rd carb. Boat would run...but not right. We know the linkage was all right, so it had to be the previous owner. Straightened out that mess, reassembled the carbs and it ran....got about 1/2 to 3/4 miles away this time and crappo. Long paddle, but at least it was with the wind. Rebuilt his fuel pump this time and replaced all the fuel lines (per above suggestion - LOL) Darn thing runs good now. Wouldn't be afraid to go out in it without a paddle now. LOL

    But, thats why I tried to stress to completly disassemble, clean and reassemble one carb at a time. Parts are inner changeable, but you can really mess things up.
     
  9. zappaf19

    zappaf19 New Member

    Messages:
    1,574
    State:
    Monticello,IN
    I have had my 3 carbs off the tower of power twice this year. Once for dirt and once because the setting was wrong in one carb. (had to measure all 3 to find which one it was. I HATE taking those off. Like they say take your time.
    Bill
     
  10. jgdishon

    jgdishon New Member

    Messages:
    62
    State:
    Snowville,Virgi
    I have four of these carb now as I bought two off of ebay and tried them on my boat. They are the ones that will run wide open or not at all. The origionals are the ones im going to rebuild, they would not idel at all I had to keep pushing the choke to get them to run. I will lay them out one at a time like you said and clean clean clean them before reassembling. I also will take digital photos of each step and post them as I go if BOC will allow me. I sure could use that blow up of the carbs bubbacat if you dont mind. Thanks again for the help.
     
  11. jgdishon

    jgdishon New Member

    Messages:
    62
    State:
    Snowville,Virgi
    I rebuilt my carbs yesterday and it was so easy! Cant beleive the local marina wanted 200.00 a piece to do it. Motor is Idealing smooth and I have 100% better throttle response. Cant wait till the weekend to try it on the lake. Bubbakat: your help was very much appreciated and very accurate. The photo drawings of the carbs you sent along with directions and specs on adjustments saved me. The old carbs had a 1/2 inch gap between the top of the high speed port and the bottom of the float on my old set up. I adjusted to .64mm I figured about half way between the .40 to .80 that was specified. That may have been the biggest part of my problem to start with. Anyway "THANKS" Bubbakat
     
  12. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Any time jeff always glad to help:cool2: