1979 Mercury thunderbolt 3cyl Reed valve location

Discussion in 'Bubba's Outboards' started by Larry, Mar 28, 2008.

  1. Larry

    Larry New Member

    Messages:
    707
    State:
    Minnesota
    Would anyone have an idea on where the reed valves are located on a 1979 Mercury thunderbolt 3cyl?
    Serial number is 5465928

    Would they be located on the Crank shaft or behind the carbs.
    Do they look like mini Air planes. V shaped?
    Any info is appreciated
    thanks
    Larry
     
  2. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Located behind the carbs and should be mounted on a round frame and the reeds themselves should be flat thin metal fins
     

  3. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    I may be wrong about the shape of them but do know they are behind the carbs.
    What makes you suspect that the reeds are bad or you just curious.
     
  4. Larry

    Larry New Member

    Messages:
    707
    State:
    Minnesota
    Bubba Cat

    Thanks for your reply,
    I've been having some problems with my motor for sometime. Started Aug of 07 Three diff people looking at it and couldn't diagnose the prob. One guy tried to tell me the reeds were on the crankshaft and that I should buy a new motor from Him... Wouldn't be worth it to fix....(Said thanks but no thanks)
    Took it to another place explained the problem.... Loosing power when running WOT... getting about 2/3 power. he replaced the reeds... They were definitely warped. Said the prob was fixed... this was done late last fall... unable to take out and test.
    River opened up and took it out for trial runs.... Little hard to start after winterising... She ran great for about 2 Min's and then when I cut the throttle she would only give me 2/3 power again after throttling up.
    Thought it might be a fuel line prob. so I replaced fuel line and put new plugs in...
    No change.
    In the last year have had the fuel diaphragm/pump replaced/ power pack/ carbs reworked. Compression checks out, 120-125 on all cyl when she is cool. Though I would like to check after she's warmed up.
    I'm bringing it back in tomorrow to be looked at. She runs fine in a tank or on muffs.
    Just when she is under load she boggs down, seems like she's only giving me 2 out of 3 cylinders. 20mph vs 30-35 that I'm used to.
    People up in MN don't like working on older motors. The just want to sell a new one.
    I kind a mechanically inclined. Though not a 2 cycle motor expert.
    If you have any ideas to point me in any direction it would be much appreciated.. I will definitely keep you in the loop with what is going on.
    thanks
    Larry
     
  5. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    That sounds more like a coil falling out or the trigger assy not doing its job. I'll look up some test that you can do and save yourself some money from those guys throwing parts at it.
     
  6. Larry

    Larry New Member

    Messages:
    707
    State:
    Minnesota
    Thank you sir. Much obliged. :wink:
     
  7. Larry

    Larry New Member

    Messages:
    707
    State:
    Minnesota
    So I have the boat in the shop. They call me yesterday stating that everything is normal and she is running fine, with muffs or in a barrel
    I tell them that the problem is when the motor is running WOT under load she's only giving 2/3rds power.
    Now I have to wait till Ice is out on the lakes, so I can show these guys whats up..... Cmon warm weather.... Melt the lakes..... The rivers are open and I want get the bite when she picks up.
    :angry::angry::angry:
     
  8. tbull

    tbull New Member

    Messages:
    3,318
    State:
    SW Ohio
    I am having a similar problem and trying to diagnose is giving me an ulcer....:angry::confused2: