Snapper High Lift Performance...

Discussion in 'Mechanic and Repair' started by lawnmaniac883, Sep 23, 2005.

  1. lawnmaniac883

    lawnmaniac883 LawnSite Silver Member
    Posts: 2,613

    Anyone have a clue why this mower is such a dog to start when warm? Black smoke (fuel) is comming out upon ignition, but until that, nothing. It runs well once it gets moving as well. Backfired three times today, twice on shutdown, once on startup. Do I need to adjust the valves or carb? Engine is a 7hp B&S ohv engine. Can get more information if needed. Thanks in advance.
     
  2. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022

    Would this happen to be a Intek engine ? Go ahead and post the model and type numbers. How old is this unit ? The first two digits of the engine serial number will tell.
     
  3. lawnmaniac883

    lawnmaniac883 LawnSite Silver Member
    Posts: 2,613

    Yes, it is an intek engine, will have model and serial #'s tomorrow.
     
  4. lawnmaniac883

    lawnmaniac883 LawnSite Silver Member
    Posts: 2,613

    Ok, got model #'s from the snapper deck, serial 41052696 model P217017BV; from the top of the engines muffler I pulled 128602 0149 E1 - 030730FA. Maybe you can make cense of all of these, thanks in advance.
     
  5. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022

    Ok, We'll have some school first; The P217 is the model unit, The 01 is the unit series, The 7 is hp and B Briggs V vertical shaft. The first two digits of the engine serial number are the year it was built 2003. Ok schools out lol
    Briggs had a problem with the camshaft heat treating on the Intek engines and it is causing the exhaust cam lobe to wear flat, As it wears the exhaust valve doesn't open as far and long enough for the gases to be emitted.
    To check for this problem remove the valve cover and spark plug and rotate the engine clockwise and watch the intake valve open then watch the exhaust valve for the same amount of opening. If the amount is less then you should contact your Briggs dealer with the engine numbers and Briggs will most likely have them shortblock the engine for you.
     
  6. lawnmaniac883

    lawnmaniac883 LawnSite Silver Member
    Posts: 2,613

    Warranty repair or no? Thanks
     
  7. lawnmaniac883

    lawnmaniac883 LawnSite Silver Member
    Posts: 2,613

    Ok, pulled the cover and plug, rocker movement is the same on both intake and exhaust rockers. No problem there, performance seems ok, but the recently developed backfiring is the larger concern for me. Strange that it backfired on shutdown and startup...I see these are unadjustable valves, clearance was fine at tdc anyway. Anything else to check for?
     
  8. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022

    Yes, The shortblock would have been warranty. Well you don't check valve clearance at TDC on this engine and if you look closely in the center of the long looking nut holding the rocker on you will see a set screw. You loosen the set screw and adjust the rocker nut. The piston needs to be positioned 1/4" past TDC compression stroke, Do this by sticking a small screwdriver in the plug hole touching the top of the piston, This will get it off the compression release. After adjusting re-tighten the set screws.
    I feel the problem your having is valve adjustment so you should check as mentioned and if they are infact ok we will have to go else where.
    Sorry, I don't have the specs. here at home on this one but I will post them around noon tomorrow.
     
  9. lawnmaniac883

    lawnmaniac883 LawnSite Silver Member
    Posts: 2,613

    Mmk, thanks.
     
  10. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022

    Ok, Both intake and exhaust set at .004-.008 I would set them around .005
    Let me know what you find !
     

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