Will not start when hot?

Discussion in 'Mechanic and Repair' started by modelnmn68, May 25, 2006.

  1. modelnmn68

    modelnmn68 LawnSite Member
    Posts: 3

    Hi i am new to the site. I have an 18hp opposing twin briggs that will not start when it is hot. What is the problem or what should i check for? Any help would be appreciated.
     
  2. khouse

    khouse LawnSite Bronze Member
    Posts: 1,465

    won't start or won't crank? choke or no choke? plug new or old? starts good cold or doesn't? it's anyones guess without info.
     
  3. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022

    Yep Need more info, Read the second thread on top of this forum........
     
  4. J&R Landscaping

    J&R Landscaping LawnSite Fanatic
    Posts: 5,096

    A little more info would be helpful!

    Could be a fuel pump going bad, but my guess would be a ignition coil! Thats the usual colpret!
     
  5. modelnmn68

    modelnmn68 LawnSite Member
    Posts: 3

    Ok the motor will run no problem all day if you left it running, but as soon as you shut it off it will not start until after there has been time to cool down to almost cool to the touch before it will start again.
     
  6. modelnmn68

    modelnmn68 LawnSite Member
    Posts: 3

    Yes it starts easy when cold with choke. After it is hot it will crank but not start with or with out choke, and plugs are new.
     
  7. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,022

    When it will not start remove the plugs, Put them back into the plug wires and hold the plug body against the intake mainfold and have someone crank the engine over. Watch the spark plugs to see if they have a nice blue spark, If not the coil is breaking down under heat and needs replaceing, If they have a nice blue spark a compression or leak-down test should be performed to check the condition of the rings and valves. If that test is OK then move to the carb. and fuel pump assembly, Possibly rebuilding it.
     
  8. Splicer

    Splicer LawnSite Senior Member
    Posts: 992

    Agreed:clapping: :clapping: :clapping:
     
  9. J&R Landscaping

    J&R Landscaping LawnSite Fanatic
    Posts: 5,096

    Are the plugs gaped correctly? That might make a difference!
     

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