B&S Quantum engine trouble!

Discussion in 'Mechanic and Repair' started by SER, May 16, 2005.

  1. SER

    SER LawnSite Member
    Posts: 60

    Hi all.
    I did a tune up on a 5HP B&S engine on a Toro mower. I changed the oil, spark plug, and installed a new needle and seat in the carb. The engine runs fine when you use it, then when you stop it to empty the grass bag, it becomes very hard to start. Someone said I should have taken the head off and checked for carbon build up, then checked the valves while I was there.
    Any suggestions here????? :realmad:
    :)
    SER
     
  2. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024

    What was the reason for replacing the needle and seat ? Does it seem flooded when you try to restart ? Are you choking on restart ? Does it start right up cold ? These questions will give me a idea where to send you !
     
  3. SER

    SER LawnSite Member
    Posts: 60

    I replaced them because I usually do this when I tune up an engine. It does not seem to be flooded, although I could be wrong. I put the throttle at the starting position when starting. It still does not start sometimes.
    What do you think about compression loss, ie, carbon build up at the head and checking the valves?
    SER
     
  4. jubiljoe

    jubiljoe LawnSite Member
    Posts: 10

    if the unit is over head valve I would check the valve clearance.
    but is sounds like the"Start" mode could be causing the problems
    if start= choke you are flooding the engine.
     
  5. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024

    I really don't believe carbon is the problem here,I'm leaning more to carb. or a coil heating up and dropping spark,Was it running ok before you tuned it up ?
    Its not necessary to replace the needle & seat with a tune-up,Only when you have a flooding or rich running problem.
     
  6. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024


    I had that thought also but I figured maybe he has owned the unit long enough to know not to choke a hot Briggs.
     
  7. SER

    SER LawnSite Member
    Posts: 60

    To Jubil Joe:

    What do you mean by start mode? You dont have to choke the machine or prime it when you retstart it?
    SER
     
  8. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,024


    In most cases a warm Briggs engine will restart without choke or prime,If you are doing so it could cause a too rich restart or flooded restart.
     

Share This Page