Briggs 5 Hp engine fowling plugs

Discussion in 'Mechanic and Repair' started by lawn6@bigpond, Sep 5, 2005.

  1. lawn6@bigpond

    lawn6@bigpond LawnSite Member
    Posts: 61

    Got a briggs 5 Hp engine that is fowling the sparkplug up . Before starting each time have to replace the plug . Runs fine until it is under load it coughs and backfires before it dies seem to use small amount of oil .

    Thinking about giving it new set of rings & seals the engines numbers are
    Mod 130902
    Type 0625
    code 02-82221806

    I should say it is on a small ride-on mower.
     
  2. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024

    Spark plugs tell a story.
    Does the plug look black and sooty or does it look like oily carbon build up ?

    It could be a carb. problem (running too rich) or a ring problem (burning oil)
    Could also be a partly sheard flywheel key also.
     
  3. lawn6@bigpond

    lawn6@bigpond LawnSite Member
    Posts: 61

    Today we found the sparkplug was not the correct one it had a RO 285 Bosch plug in it . replace it with RJ19LM Champion.

    The plug we removed was not oily was just blackend up

    Fly wheel key is o.k

    What is the carby setting for this engine ??

    What about decorbon the head would that help ??
     
  4. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024

    There is not just one setting, It differs from engine to engine. Start with the adjuster at 1 1/2 turns out and adjust either direction until a smooth hi speed is achieved of course with the air filter in place. while saying that what shape is the air filter in ? Too much oil in it and it could cause a rich run also.
    Being that the engine is 3 yrs. old a decarbon wouldn't hurt anything but I don't believe that is your problem.
     
  5. lawn6@bigpond

    lawn6@bigpond LawnSite Member
    Posts: 61

    Thank for the info on that , Have removed the head new rings is needed got piston movement sideways. The guy said it had not use much oil but how much is not much . So going give it new set of rings and a good clean up to reset the valves what are these set at ?
     
  6. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024

    If the piston has too much side play the cylinder is in need of a bore job, Take the new top compression ring and insert it in the cylinder alone about 1/2" down inside and check the end gap with a feeler gauge. It shouldn't be more than .035 then take the piston with the rings removed and slide it upside down on top of the new ring down to the lower part of the cylinder and check again, This will show cylinder tapper. Perform the same check with the new oil ring but this one is .045 max.
    Although a new piston will not remove all the side movement I would suggest one anyway because it should help.
    The intake valve clearance is .005 to .007 with the piston 1/4" past top dead center compression stroke and the exhaust is .009 to .011.
    Rod screw torque is 100 in. lbs., Head bolts 140 in. lbs. in a cris-cross pattern, And oil pan or sump is 120 in. lbs.
    Good luck
     

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