Shop Products
Houzz Logo Print
newbreed_gw

Briggs and Sratton Quantum 5.5 HP no SPARK

newbreed
11 years ago

Lawnmower is a B&S Quantum XE vertical shaft, mower was running fine and has always started on first pull (by the way it is a prime start type, carb has no fuel or air adjustments and electrical system is point less uses coil or magnetron). The other day was mowing lawn and noticed the carb bracket was cracked and vibrating bad, shut motor off removed carb, linkages, kill wire and defective bracket. Installed new bracket and installed all associated parts. Primed carb (also when carb was off cleaned it all out and checked float) set to start pulled cord no start tried over and over, checked spark at spark plug NO spark, checked kill wire GOOD, checked run cable GOOD, checked gap on coil GOOD, also checked strength of magnets GOOD...Replaced coil and plug (COIL installed This Side Out readable) used a business card for gap, hooked spark plug back up and tried again with kill wire disconnected ...still no spark...What would cause a perfectly good running motor to quit giving off spark, when the problem was with a broken bracket to begin with? Aren't the main things for spark are coil, spark plug and kill wire? Any help in this matter will be greatly appreciated...."STUMPED"

Comments (12)

  • bill_kapaun
    11 years ago

    The only thing left is the fly wheel magnet.

    Otherwise ????

  • newbreed
    Original Author
    11 years ago

    I don't know, the magnets are pretty strong, also there is no corrosion on them?

  • tomplum
    11 years ago

    Not to seem condescending, but a known good coil and spark plug will generate spark. If the other coil had spark before, it isn't likely that 2 coils are bad. Possibly the method of checking spark is incorrect? It would be more likely that the intake tube/ gasket/ o ring is damaged from the broken support bracket. It could be also that a linkage issue is holding the throttle plate closed.

  • newbreed
    Original Author
    11 years ago

    I checked all that, carb is working as advertised, also R2d the O'ring and the carb gaskets (both on the bracket and on the air cleaner side)..You have me thinking though, how would the intake tube have anything to do with the spark? Does the governor have anything to do with the spark or does it come into play only after the motor is running to regulate the fuel intake?

  • baymee
    11 years ago

    Have you tried to remove the ground wire from the coil and then try for spark? It's rare, but the grounding wire from the coil can be burned through and grounded to the block. The governor doesn't affect spark, but did you check for free movement of the throttle linkage, as Tom suggested?

  • lbpod
    11 years ago

    Just a shot in the dark here, but is it possible that
    there are coils that require that the ground terminal
    be grounded in order to produce spark. I'm just guessin
    here, because nothing else makes sense.

  • tomplum
    11 years ago

    The intake tube has nothing to do with spark. They will however wear or break because of the loose support bracket. So remove it when you have the shroud off and have a look. If you have a known good coil -installed properly w/ the kill wire disconnected and the terminal not bent against the coil legs, a known good spark plug, a flywheel with good magnets as you say, and enough rpms on the pull- you have spark. If you don't feel you do, I suspect the spark test itself. I'm still unsure how you are checking for spark and if that is correct. The governor also has no spark connection.

  • newbreed
    Original Author
    11 years ago

    Thank you all for your inputs...the way I am checking for spark is...I removed the plug took the boot off of the spark plug wire to the coil, held it about 1/16 of an inch away from the casing pulled the cord, looked for spark, NO spark...next I disconnected the kill wire terminal from the side of the coil (wire comes out of terminal and branches out to the throttle linkage and the brake)I again held the plug wire next to the casing, pulled cord looked for spark, NO spark...I also did both checks with the plug hooked up and held it close to fhe casing, pulled cord and still NO spark (this check was performed with the old coil and plug and the new coil and plug) Finally I held the plug wire in my hand and pulled the cord, I felt a shock a little bit, but not enough to make me let go (it wasn't a jolt like it should be) I was thinking, I should be able to perform all these tests without the carb or linkages hooked up right, since I am checking for spark and not combustion?

  • bill_kapaun
    11 years ago

    What I use for an ignition tester is an old spark plug with the gap widened out to around .090" or so.

    Stick the plug in the boot and ground the plug to the engine BLOCK. (not sheet metal or?? because it doesn't necessarily have a good ground)
    Pull cord and observe.

  • newbreed
    Original Author
    11 years ago

    I was using the Bolt on the casing (the steel one) , and I scraped off the paint and checked with meter, it is a good ground. I also checked it the way you suggested, still no spark...thanks for helping me, I know once I, or we figure this out, I will be sure to post it and let everyone know...never had this problem before...probably something very simple, as usual.

  • newbreed
    Original Author
    11 years ago

    Troubleshot using parts from a good running lawnmower, found out that I purchased a bad coil from the dealer, who'd of thought 2 bad coils," Mystery Solved" Thanks Alot for your help!

  • Brandon Smith
    11 years ago

    I'm sorry perhaps I missed this but did you replace the coil? Is this one of those old Briggs/Tecumseh engines (is there an Indian anywhere on the engine)?

    Perhaps the replacement coil is bad/defective, wouldn't be the first time a new part didn't work.

    GL

0