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16 HP Vanguard oil blowing in carb.

Discussion in 'Mechanic and Repair' started by rob1325, Apr 2, 2003.

  1. rob1325

    rob1325 LawnSite Senior Member
    Posts: 682

    I have a weird problem with my 16 HP Vanguard thats on my leaf blower. It is blowing a lot of oil into carburetor through breather tube and the oil turns black just after few hours of use. I have to add about half quart a day because of this. I email Briggs & Stratton and they told me to replace seals on dipstick. So I replaced the O-ring on dipstick and the seal on crank where dipstick slides in. This still didn't help. I then replaced my breather valve and this also didn't help. I then emailed them back and they tell me to bring it to dealer, but motor is out of warranty. I never ever take my equipment to dealer unless it is under warranty. I usually am able to fix it myself, but this problem has me stumped. Is the piston rings shoot? I would appreciate any help or suggestions you guy may have.

    Thanks,

    Rob
     
  2. Fish

    Fish LawnSite Member
    Posts: 139

    You likely have a blown head gasket, run the engine for a
    minute with the valve cover removed to confirm.
    Fish
     
  3. Richard Martin

    Richard Martin LawnSite Fanatic
    Posts: 14,700

    It does sound like the rings are gone.
     
  4. Remo Sid

    Remo Sid LawnSite Member
    from USA
    Posts: 55

    head gasket
     
  5. rob1325

    rob1325 LawnSite Senior Member
    Posts: 682

    I will look at head gasket but leaning towards rings. Oil always turns black after couple of hours on machine. If note head gasket then will tear down motor and replace rings and gaskets.

    Thanks,

    Rob
     
  6. John DiMartino

    John DiMartino LawnSite Silver Member
    Posts: 2,555

    Run a compression test. I think its a head gasket.The oil turning black is the exhaust gettign into the oil thru the blown gasket.
     
  7. rob1325

    rob1325 LawnSite Senior Member
    Posts: 682

    I will do the compression test. The motor is now acting worse. It runs really bad. I have to keep choke on to make it run. I cleaned out the carb and adjusted it and still needs choke on to run. I will tear it down and look at everything,


    Thanks,

    Rob
     
  8. Fish

    Fish LawnSite Member
    Posts: 139

    A compression test will not tell you much, as the amount of
    compression going to the crankcase is slight. The area of
    the head gasket that usually blows is the area between the
    cumbustion chamber and pushrods. If you remove the valve
    covers then start the engine, you will likely see which gasket is blown, but you may have a few drops of oil thrown about,
    but then you will know for sure what your problem is, as I
    seriously doubt that it is the rings.
     
  9. John DiMartino

    John DiMartino LawnSite Silver Member
    Posts: 2,555

    Fish,no matter where the gasket is blown a compression test will show which cyl needs to be torn down.You wil be able to see the lower reading on the guage. Once the gasket is off,and if its not blown,and the head/vaves check out ok,then he need to go deeper.
     
  10. Fish

    Fish LawnSite Member
    Posts: 139

    I won't argue about it, but how much lower? If there is no
    head gasket leak, can you say for sure that both cylinders will
    show identical readings?
    A tiny blow in a head gasket may only show a 5-10 lb. drop
    in compression, thus fooling the person testing that he does not
    have a gasket problem.
    That tiny leak, however, can pressurize the crankcase in a big way.
    Just trying to save the original poster from running out and
    buying a compression gauge, he has bought enough stuff he
    doesn't need.
     

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