Briggs & Stratton 98902 Repair

Discussion in 'Mechanic and Repair' started by Ben98gs, Aug 10, 2005.

  1. Ben98gs

    Ben98gs LawnSite Member
    Posts: 18

    I have a Briggs & Stratton Model 98902 Type 2098 lawn mower (inherited from sister) that I cannot get to start.. Where should I start with troubleshooting... I replaced both the air filter (that didnt look that bad) and the spark plug (which was pretty fouled) and yet it still wouldnt start.

    I currently have the motor completely torn down, cylinder wall and head looks fine (some carbon build up). The combustion chamber is pretty built up with carbon and the intake valve had quite a bit of build up (not the exhaust though). Is there anything besides cleaning these parts that I should do??? Especially since I have it completely apart??? All the internal components show no sign of wear, I forgot to check for spark, but I know that when I tore it down, the plug smelled of fuel... Possibly the ignition coil???

    What do you guys think???
     
  2. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    Since you already have it apart go ahead and decarbon everything and reassemble, Then check for spark, Given that you smelled fuel it probably doesn't have spark. The most common things to check when a engine wont start are compression, spark and fuel.
    If this unit has the stop bail on the handle these cables stretch in time and will not disengauge the stop switch so no spark, Just something else to check.
     
  3. Ben98gs

    Ben98gs LawnSite Member
    Posts: 18

    Thanks... Just for good measure I ordered the full gaskit kit AND armature magnetico (or whatever you call the ignition system basically)... I check the cable/switch and it seemed fine... I didnt clean it before hand, but when it was apart, I cleaned everything as good as I can.

    I will let you know what happens in about 3-5 days when my stuff gets here.

    Is there a need to remove the valves to clean them real good??? If so, how do I remove them (and then get them back in)... I have opened them the best that I can and cleaned up what I could...

    Thanks,

    Ben
     
  4. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    That should be just fine, It takes a small valve spring compressor to remove the springs properly.
     
  5. Ben98gs

    Ben98gs LawnSite Member
    Posts: 18

    Alright, I got her all back together and after one minor problem (I had the crank 180* off) she starts and runs...

    BUT... the mower will run great for about 20 minutes and then after that it starts to "sputter"... It will stay running, but it is almost as though you hit the speed controller all the way down to slow. What could be the cause of this??? Like I said, it will run great for about 20 minutes, but that is only enough time to do about half of the yard.

    At least she runs I suppose, but I would still like it running correctly :help:
     
  6. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    Given the fact you already installed a new coil that is counted out.
    It's possible the carb. diaphragm is heating up and malfunctioning and it's starving for fuel. Take it out and mow again and when it acts up push the primer bulb one time and see if it doesn't pick back up, If so I would replace the diaphragm and clean the carb. with choke spray cleaner, Make sure the main jet is open and the fuel pick-up tube screen is clean. Clean the tank good and reassemble.
     
  7. Ben98gs

    Ben98gs LawnSite Member
    Posts: 18

    I fixed it last night, but thanks for the information, you were virtually right on... I took the carb back apart, and the diaphragm area had somehow slipped out and so it wasnt sealing and was leaking the gas out from that area. I realigned everything and put her back together and ran her for another 20 minutes (even though I had no lawn left to mow, the neighbors probably think I am crazy) and no problems.

    Thanks for the help, you are awesome :waving: :drinkup:
     
  8. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023


    Thanks ! Glad you got her going.
     

Share This Page