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-   -   Briggs 16.5 will not run, it is firing (https://www.askmehelpdesk.com/showthread.php?t=372035)

  • Jul 4, 2009, 10:17 PM
    krazziee
    Briggs 16.5 will not run, it is firing
    Hi all ,
    I have a 16.5 briggs ohv engine. It was fine ,ran good, shut down ,next week went to use it ,will not crank, solinoid on carb is working, has compression,it is firing, seems to be in time, put finger in spark plug hole and watched plug arc at the compreeion stroke, checked key on flywheel and it is OK , poured a little fuel into carb,
    It will not pop, poot, smoke or anything.
    I do not understand
    Can anyone help me?
    Thank you all .
    Richard
  • Jul 4, 2009, 11:56 PM
    21boat

    Very confusing here.
    Quote:

    will not crank, has compression,it is firing
    Yet you put gas in carb and no pop etc. How did you turn the flywheel?

    Did you check the safety switch in the seat?

    Also did you test the solenoid an jump it with a screw driver to see if that turns the starter? If jumping the solenoid doesn't kick starter then solenoid is bad.

    http://www.arcomarine.com/xhtml/Tech...%20circuts.pdf

    Getting back to the spark end.

    Just because you have spark doesn't mean its "hot" enough to fire cylinder. There is a spark tester for that but to get that done backyard style take out a plug and cut off the curve of the plug. Now there should only be a straight end on it. Ground it to the head and see if the ARC of the spark jumps to it. If not then you have a weak coil..

    Get back after testing the solenoid that sends juice to the starter
  • Jul 5, 2009, 05:54 AM
    krazziee

    Thank you 21boat
    This is on a trailer mower so there is no safety switch. The starter is working fine , spins the engine as it should, had the carb off and apart and cleaned, the solenoid is working with the key switch, poured a little gas in carb and spun with starter, nothing -no pop or anything, also put in a new spark plug, seems to fire good grounding on the head,
    How would you check the coil ?
  • Jul 5, 2009, 10:21 AM
    21boat

    Basically checking the coil is checking the spark strength. I still think this is really leaning to a weak spark which would be a weak coil, Did you try cutting off a spark plug as I suggested so this can be taken out of the equation?

    There is a cheap spark plug tester in a store called "Harbor Freight"

    I would suggest also a weak fuel pump but gas in the carb should bypass that. So we are back to the spark/weak ignition coil.
  • Jul 5, 2009, 02:56 PM
    krazziee
    21boat this thing will not let me rate your answer which was helpful and I thank you very much.

    Well the problem was a bent intake push rod, the reason the rod was bent is because the intake valve stem seized to the head. Heavy carbon build up . I guess it was running and when shut down it seized up and when trying to crank the next time it bent the push rod. So there it was, removed head, worked the valve free, removed valve, cleaned off carbon , straighten push rod and checked in lathe. Reassembled and it cranked up instantly. It has a steel exhaust push rod and an aluminum intake pushrod.

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