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7 horse briggs backfires and pops at an idle

Discussion in 'Mechanic and Repair' started by Robert Doubrava, Aug 31, 2001.

  1. Robert Doubrava

    Robert Doubrava LawnSite Senior Member
    Messages: 342

    also, that fuel filter was dirty as heck. my dad sprayed lubricant in it and tapped it on a shop rag and all this rust came out. i think there is two things to blame. the fuel tank is made of metal, and my dad took the screen off of the fuel shut off valve because it is always getting clogged up. will any one please help me with my last post? :(
  2. vipermanz

    vipermanz LawnSite Bronze Member
    Messages: 1,773

    did the rpm's increase?
  3. Eric ELM

    Eric ELM Husband, Father, Friend, Angel
    Messages: 4,830

    Taking that screen off of the shut off is just letting rust get through to the fuel filter and clogging it up. You have to eliminate the source of the problem, that tank.

    It sounds like your main problem is the metal gas tank that is full of rust. See if you can get a plastic tank to replace it or take off the metal one and clean it up some how.

  4. khouse

    khouse LawnSite Bronze Member
    Messages: 1,465

    Remove the tank and fill it 1/4 full of gravel and a cup of sand if you have it. Shake the tank for at least 10 minutes. Pour out the gravel mix and rinse with Kerosene or Diesel -(not gas) until clear. Reinstall the tank and fill with gas. Change the filter and your good to mow.
  5. Guido

    Guido LawnSite Silver Member
    Messages: 2,087

    Maybe with a parts cleaner if you have one.

    Next, you put a handfull or two of gravel in there and shake it up for a while, rinse, and repeat untill all the rust and buildup is out.

    It works I've done it before on an old toro walk behind edger that had fuel sitting in it for 6 years.

    Good Luck!
  6. vipermanz

    vipermanz LawnSite Bronze Member
    Messages: 1,773

    i'd dump that tank, get a plastic one, new fuel filter, new fuel lines, clean the carb, and try that out
  7. Robert Doubrava

    Robert Doubrava LawnSite Senior Member
    Messages: 342

    i can't because the gas tank is riveted to the engine cover. i would have to spend a lot of money to replace it, too! thanks for your help. i appreciate it.

  8. Kevin M.

    Kevin M. LawnSite Member
    Messages: 137

    I have had a Briggs just like yours and I started to replace all that stuff and then went to Grainger and got a new Kohler 7 hp engine for $ 200 bucks and that was two years ago and always had problems with backfiring with the Briggs and the Kohler just keeps huming along every day on a spray rig for a chemical truck.
  9. Robert Doubrava

    Robert Doubrava LawnSite Senior Member
    Messages: 342

    i just finished mowing a lawn with 2 foot tall grass with only a push mower! i did it by myself, too. no help from dad! :D i had fun, though. by the way i found a 5 horse briggs at www.smallenginewarehouse.com it is for riding mowers, i think. it is an old model, but it is brand new and it has a warranty on it as well. i think its only 175.00. it is a vertical shaft engine, i might add.lthe rider used to have a 6 horse on it but my grandfather burned it up!:eek: thanks for all the advice, guys!
  10. vipermanz

    vipermanz LawnSite Bronze Member
    Messages: 1,773

    aww, rivets aren't anything much for a wizard or dremel to handle with a cutoff disc on it, zoooooooommmmmm!

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